CHAPTER ONE: PIT-LINE
Railway air brake
An air brake is a conveyance braking system actuated by compressed air. Modern trains rely upon a fail-safe airbrake system that is based upon a system on a locomotive
Piping diagram from 1920 of a Westinghouse E-T Air Brake
design patented by George Westinghouse on March 5, 1872. The Westinghouse Air Brake Company (WABCO) was subsequently organized to manufacture and sell Westinghouse's invention. In various forms, it has been nearly universally adopted. The Westinghouse system uses air pressure to charge air reservoirs (tanks)on each car. Full air pressure signals each car to release the brakes. A reduction or loss of air pressure signals each car to apply its brakes, using the compressed air in its reservoirs.
Background
Prior to the introduction of air brakes, stopping a train was a difficult business. In the early days when trains consisted of one or two cars and speeds were low, the engine driver could stop the train by reversing the steam flow to the cylinders, Westinghouse’s invention. In various forms, it has been nearly universally adopted. The Westinghouse system uses air pressure to charge air reservoirs (tanks)
on each car. Full air pressure signals each car to release the brakes. A reduction or loss of air pressure signals each car to apply its brakes, using the compressed air in its reservoirs.
A comparatively simple brake linkage
Overview
In the air brake's simplest form, called the straight air system, compressed air pushes on a piston in a cylinder. The piston is connected through mechanical linkage to brake shoes that can rub on the train wheels, using the resulting friction to slow the train. The mechanical linkage can become quite elaborate, as it evenly distributes force from one pressurized air cylinder to 8or 12 wheels. The pressurized air comes from an air compressor in the locomotive and is sent from car to car by a train line made up of pipes beneath each car and hoses between cars. The principal problem with the straight air braking system is that any separation between hoses and pipes causes loss of air pressure and hence the loss of the force applying the brakes. This deficiency could easily cause a runaway train. Straight air brakes are still used on locomotives, although as a dual circuit system, usually with each bogie (truck) having its own circuit. In order to design a system without the shortcomings of the straight air system, Westinghouse invented a system wherein each piece of railroad rolling stock was equipped with an air reservoir and a triple valve, also known as a control valve. The triple valve is described as being so named as it performs three functions: Charging air into a air tank ready to be used, applying the brakes, and releasing them. In so doing, it supports certain other actions (i.e. it 'holds' or maintains the application and it permits the exhaust of brake cylinder pressure and the recharging of the reservoir during the release). In his patent application, Westinghouse refers to his 'triple-valve device' because of the three component valvular parts comprising it: the diaphragm-operated poppet valve feeding reservoir air to the brake cylinder, the reservoir charging valve, and the brake cylinder release valve. When he soon improved the device by removing the poppet valve action, these three components became the piston valve, the slide valve, and the graduating valve. • If the pressure in the train line is lower than that of the reservoir, the brake cylinder exhaust portal is closed and air from the car’s reservoir is fed into the brake cylinder to apply the brakes. This action continues until equilibrium between the brake pipe pressure and reservoir pressure is achieved. At that point, the airflow from the reservoir to the brake cylinder is lapped off and the cylinder is maintained at a constant pressure.
If the pressure in the train line is higher than that of the reservoir, the triple valve connects the train line to the reservoir feed, causing the air pressure in the reservoir to increase. The triple valve also causes the brake cylinder to be exhausted to atmosphere, releasing the brakes.• As the pressure in the train line and that of the reservoir equalize, the triple valve closes, causing the air pressure in the reservoir and brake cylinder to be maintained at the current level. Unlike the straight air system, the Westinghouse system uses a reduction in air pressure in the train line to apply the brakes. When the engineer (driver) applies the brake by operating the locomotive brake valve, the train line vents to atmosphere at a controlled rate, reducing the train line pressure and in turn triggering the triple valve on each car to feed air into its brake cylinder. When the engineer releases the brake, the locomotive brake valve portal to atmosphere is closed, allowing the train line to be recharged by the compressor of the locomotive. The subsequent increase of train line pressure causes the triple valves on each car to discharge the contents of the brake cylinder to atmosphere, releasing the brakes and recharging the reservoirs. Under the Westinghouse system, therefore, brakes are applied by reducing train line pressure and released by increasing train line pressure. The Westinghouse system is thus fail safe—any failure in the train line, including a separation ("break-in-two") of the train, will cause a loss of train line pressure, causing the brakes to be applied and bringing the train to a stop. Modern air brake systems are in effect two braking systems combined:• The service brake system, which applies and releases the brakes during normal operations, and• The emergency brake system, which applies the brakes rapidly in the event of a brake pipe failure or an emergency application by the engineer. When the train brakes are applied during normal operations, the engineer makes a "service application" or a "service rate reduction”, which means that the train line pressure reduces at a controlled rate. It takes several seconds for the train line pressure to reduce and consequently takes several seconds for the brakes to apply throughout the train. In the event the train needs to make an emergency stop, the engineer can make an "emergency application, "which immediately and rapidly vents all of the train line pressure to atmosphere, resulting in a rapid application of the train's brakes. An emergency application also results when the train line comes apart or otherwise fails, as all air will Railway air brake 4also be immediately vented to atmosphere. In addition, an emergency application brings in an additional component of each car's air brake system: the emergency portion. The triple valve is divided into two portions: the service portion, which contains the mechanism used during brake applications made during service reductions, and the emergency portion, which senses the immediate, rapid release of train line pressure. In addition, each car's air brake reservoir is divided into two portions—the service portion and the emergency portion—and is known as the "dual-compartment reservoir”.
Brake System
Air Brake System
Air brake system was initially provided on Rajdhani & Shatabdi coaches. From April’94 onwards all coaches being manufactured by production units will have air brakes. Progressive conversion from vacuum to air brakes has also beings undertaken.
4.2.2 Coaches had been provided with twin pipe graduated release air brake system. The brake pipe is charged to 5 kg/sq. cm while the auxiliary reservoir charged by the feed pipe at 6 kg/sq.cm through check valve and choke from the locomotive. To apply brakes the pressure of the brake pipe is reduced which in turn charges the brake cylinder through the distributor valve to a pressure 3.8 kg/sq.cm. When the brakes are released the brake pipe is charged to 5 kg/sq.cm and the brake cylinder air is exhausted to outside atmosphere. The release spring in the brake cylinder forces the piston to go inside the brake cylinder thereby releasing the brakes.
The Air brake system on a passenger coach consists of the following main components:-
4.2.3 Brake cylinder : There are two 355 mm (14”) brake cylinder mounted o the underframe which are fed by a common distributor valve.
4.2.1 Brake pipe : This is charged from the locomotive at 5 kg/cm2 and causes application and release of brakes due to change in its pressure through the locomotive control system.
4.2.5 Feed pipe : This is charged at a pressure of 6 kg/cm2 and keeps the auxiliary reservoir charged at full pressure even when brakes are applied.
4.2.6 Distributor valve : This is connected to the brake pipe, auxiliary reservoir & the brake cylinders and controls the pressure in the brake system.
CLASSIFICATION OF AIR BRAKE SYSTEM
Air Brake System |
Direct Release Graduated Release |
Single Pipe Twin Pipe
Operation Cycle:-
a. Charging stage
b. Graduated application stage
c. Graduated release stage
Principal of Operation of Twin Pipe Graduated Release Air Brake System:
Charging the Brake System
§ Brake pipe throughout the length of the trains is charged with compressed air at 5 kg/ cm2.
§ Feed pipe throughout the length of train is charged with compressed air at 6 kg/ cm2.
§ Control Reservoir is charged to kg/ cm2.
§ Auxiliary Reservoir is charged to 6 kg/ cm2
Brake Application Stage:
§ For Brake application the brake pipe pressure is dropped by venting air from the driver’s brake valve. Subsequently the following actions take place.
§ The control reservoir is disconnected from the BP.
§ The distributor valve connects the auxiliary reservoir to the brake cylinder and the brake cylinder piston is pushed outward for application of brakes.
§ The auxiliary reservoir is however continuously charged from feed pipe at 6 kg/ cm2.
Reduction in BP Pressure during graduated application Stage:
a. Minimum application – 0.5 to 0.8 Kg/ cm2
b. Service application- 0.8 to 1.0 Kg/cm2
c. Full Service application – 1.0 to 1.5 Kg/cm2
d. Emergency application – 5 Kg/ cm2
Brake Release Stage:
§ Brakes are released by recharging brake pipe to 5 kg/ cm2 pressure through the drivers brake valve.
§ Distributor valve isolates the brake cylinder from AR
§ The brake cylinder pressure is vented through DV and BC piston moves inward.
Function of the components:
Brake Pipe and Feed Pipe Hoses:
In order to connect two successive coaches, the brake pipe and feed pipe, installed on the underfarme, are fitted with flexible hoses. Accordingly the hoses are named as BP hose and FP hose.
Cut – Off Angle Cock:
Cut-off angle cocks are provided on the air brake system to facilitate coupling and uncoupling of air hoses.
Isolating Cock:
Isolating cock are provided on the air brake system for isolating components in case any of these does not function properly on run.
Brake Cylinder:
Brake cylinder are provided for actuating the brake rigging for application and release of brakes.
Brake Rigging:
Brake rigging is provided to control the speed of the coach by transferring the braking force from brake cylinder to wheel tread.
a. Bogie Brake Rigging
b. Coach Underframe Brake Rigging.
Two Types Of Bogie Frame:
1. 16.25t axle load bogie
2. 13t axle load bogie
Slack Adjuster:
Slack adjuster is a device for automatic of clearance/ slack between brack blocks and wheel.
Distributor Valve ;
1. Charge the brake system
2. Helps in graduated brake application.
3. Helps in graduated brake release
4. Limits maximum brake cylinder pressure
5. Controls the time for application and release
6. Facilities complete discharge of air
7. Protects overcharging of CR
8. Quickly propagates reduction of pressure in brake pipe by pressure reduction arrangement locally.
Dirt Collector:
Dirt collectors are provided to collect dirt, present in the compressed air, before it enters the DV and the AR.
Check Valve with Choke:
Check valve permits the flow of air from the feed pipe to the AR, but not in the reverse direction.
The choke is incorporated for even filling of AR.
Auxiliary Reservoir:
Auxiliary reservoir is provided in the air brake system for storing the compressed air, which is to be supplied to the brake cylinders at the time of application.
Common Pipe Bracket:
It is permanently located (mounted) on the under-frame of a vehicle. It is provided for use with any make of DV.
Guard’s Emergency Brake Valve:
Guard’s emergency brake valve is provided in the guard’s compartment to initiate brake application by the guard in case of any emergency.
Passenger Emergency Alarm Signal (PEASD & PEAV)
The function of Passenger Emergency Alarm Signal System is to apply brakes and to give an audio visual signal to drive when the chain is pulled inside a coach. The PEASD and PEAV works in combination.
Train Maintenance
WASHING AND CLEANING OF COACHES
1. Platform cleaning and washing:- whenever washable aprons are available on the platforms , the time available before the terminating trains are pulled out into the yard, should be utilized for inside sweeping and toilet cleaning.
2. External cleaning and washing:-
2.1. All the old labels tied on the window bars or kept in label holders should be removed. Care should be taken to avoid damage to the paint.
2.2. Before starting washing and cleaning operations, all shutters, both glass and venetian, should be pulled down on the side which is taken up for washing and cleaning, and destination boards removed.
2.3. All exterior panels should hosed with water and brushed down diluted soft soap solution. The strength of solution may be increased or decreased according to the quality of detergent material available.
2.4. Overhead tank should be completely filled with fresh water. Every three months, tanks should be fully drained, flushed thoroughly, examined for visible damage and tested for leaks. Water filling pipes should be properly checked, leaks repaired and then defective or missing covers invariably replaced.
2.5. All destination board should be washed and cleaned and refitted on the coaches to indicate correct destination of the outgoing coach.
3. Cleaning of buffer and screw coupling:-
3.1. Buffer plunger should be scrubbed with a scraper to remove dirt and muck. Thereafter they should be wiped clean with cleaning oil and rubbed with coir rope. Graphite grease should be applied on the buffer face.
3.2. Screw coupling threads should cleaned with wire brush to remove all the dirt and dust. Thereafter, it should be cleaned and given a light coat of oil.
4. Interior cleaning of upper class, lower class and air conditioned coaches
4.1. All ashtrays should be emptied and cleaned. The magazine pocket should also be checked and cleaned. All ceiling panel should be wiped with a duster. All varnish finished, painted or polish finished panels or laminated plastic panel should be dusted and dry clean. Cushion should be cleaned with duster. All window sills should be cleaned with wet duster
In lower class coach all panel should be wiped with duster. All varnished finished, painted, polish finished or laminated plastic should be dusted and cleaned. All window should be wiped dry, dust from the corner and ends cleaned. The flooring should be washed, cleaned and swept dry to prevent slipping.
MAINTENANCE SCHEDULES
1) Types and periodicity of schedules
i. To maintain coaching stock in good condition, the following maintaince schedule are prescribed to be carried out in carriage depots on divisions:
Types of Schedule
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Periodicity
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1) Trip Schedule
2) Schedule ‘A’ or monthly examination.
3) Schedule ‘B’ or Trimonthly Examination.
4) Schedule ‘C’ or Half yearly examination.
5) Intermediate lifting of BEML coaches.
6) Special Schedule.
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At the end of each trip or as prescribed.
1 month +/- 3 days.
3 month +/- 3 days.
6 month +/- 7 days.
6 month +/- 7 days.
As prescribed by railway.
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Maintenance History Card:
For proper record and check of maintenance schedules, the base depot will maintain a “ Coach Maintaence History Card (MHC).
Trip Schedule Examination:
This examination may be given at the primary maintence depot or the secondary maintence depot.
Coaches shall be washed and cleaned thoroughly from outside and inside.
The following items of work should be attended during the trip schedule examination.
a. Underframes
b. Bogie frames
c. Axel boxes
d. Axel guard
e. Springs
TPYES OF SCHEDULE EXAMINATION
Schedule ‘A’ Examination
1 Schedule ‘A’ is required to be given every month at the nominated primary maintenance depot within the normal primary maintenance time on a washing line. A grace period of three days either side is allowed to synchronize it with the trip schedule. A coach need not be detached from the rake for Schedule ‘A’ examination unless it requires such repairs which cannot be attended to on the washing line or within the prescribed maintenance time on the washing line.
2 The following items of work should be attended during Schedule ‘A’ examination, i.e., monthly examination :-
(i) All items of trip schedule.
(ii) Intensive cleaning coaches.
(iii) Intensive cleaning of lavatory pans and commode with Vim or equivalent.
(iv) Painting of commode chutes from inside and outside with black anti-corrosive paint after scraping and thorough cleaning.
(v) Paining of commode from outside after cleaning.
(vi) Thorough flushing of tanks.
(vii) Checking of water pipes, flush pipe, flushing cocks, push cocks, etc., for ease of operation and free flow of water.
(viii) Thorough disinfection of all compartments.
(ix) Thorough cleaning of chimneys of dining cars, buffet cars, tourist cars and inspection carriages by wire brushes.
(i) Thorough inspection of train pipe, hose pipes including their cages, vacuum cylinders, siphon pipes and vacuum system.
(xi) Testing of cylinders and train pipe joints with exhauster under 51 cms of vacuum.
(xii) Clearing, greasing and testing of alarm chain apparatus under full vacuum with a spring balance and cleaning and checking of clappet valve for leakage.
(xiii) Cleaning of DA valve as indicted.
(xiv) Examination and replacement, where necessary, of brake gear pins, split pins, safety loops/brackets and their securing devices.
(xv) Examination for wear and replacement, where necessary, of brake hanger pins, brake blocks and brake heads (in case of composite type brake blocks).
(xvi) Thorough inspection and repairs of draw gear.
(xvii) Thorough inspection and repairs of buffers.
(xviii) Checking and replenishing of oil in side bearer baths of ICF & BEML coaches.
(xix) Checking and replenishing of oil in dash pots of ICF coaches with specified grade of oil of it is bellow 60 mm in tare condition. Overfilling of dash pots should be avoided.
(xx) Oiling of plain bearing axle boxes.
(xxi) Lubricating of IRS bogie side bearers and centre pivots with graphite flakes.
(xxiii) Thorough check and repairs of SLR doors for easy and smooth operation and correct alignment and loose screws, etc.
Schedule ‘B’ Examination
1 Schedule ‘B’ is required to be given every three months at the nominated primary maintenance depot within the normal time allowed for primary maintenance on a washing line. A grace period of 3 days on either side of the limit of 3 months may be allowed to synchronize it with the trip schedule. Coach need not be detached from the rake for purpose of this examination unless it requires such repairs which cannot be attended to on the washing line or within the prescribed maintenance time on the washing line.
2 The following items of work should be attended during Schedule ‘B’ examination. i.e. trimonthly examination.
(i) All items of Schedule ‘A’
(ii) Greasing of laminated bolster spring ICF coaches with soft graphite grease.
(iii) Painting of lavatories from inside.
(iv) Thorough inspection and repairs of brake gear components.
(v) Examination, overhauling and testing of alarm chain apparatus.
(vi) Overhauling of release valve, replacement of its diaphragm and sealing washer, if necessary.
(vii) Examination of neck rings and their replacement, if necessary.
(viii) Testing and repairs of roof, especially the one laid with over and underlays of rubberoid sheet before monsoon begins.
(ix) Thorough checking of trough floor, turn unders, etc. from underneath for corrosion.
(x) Touching up of painted / printed portion, if faded or soiled.
Intermediate Overhaul
1 All BEML type bogies and bogies of such ICF coaches which are working on rake links earning more than 2 lakhs kms. Per annum shall be given IOH after six months of the date of last POH or the previous IOH. Similarly, bogie vehicles overdue POH should be given intermediate lifting examination before they are allowed to run on line, to ensure fitness for service for a period not exceeding three months.
2 During this lifting schedule, bogies/under frame members and body including trough floors of integral type coaches should be thoroughly examined and all pats of running gears are repaired/replaced as necessary. The bogie frames should be particularly checked to detect damage, cracks or deformation and necessary repairs carried out. Where it is not possible for the maintenance depot to do these repairs or are prohibited to be done in the maintenance depots, the bogies should be sent to the shops for carrying out these repairs.
Special Schedule
1 For high speed trains and some special coaches like Power Vans, etc. special maintenance schedules.
Bogies
1 General
The main constructional and design features of the ICF/RCF all-oil, Schlieren, BEML and IRS – Built bogies used on mainline BG coaches are briefly described
1.2 All – Coil ICF Bogie
1.1.1 The bogie frame is built from I sections fabricated by welding. Axles are located on the
2. Side Bearers
The side bearer arrangement consists of a mechanized steel wearing plate kept immersed in an oil bath on the bogie bolster. There is a floating bronze wearing piece with a spherical top surface on which the coach body rests. The whole arrangement is provided with a cover to prevent entry of dust in the oil sump.
3. Anchor Links
The floating bogie bolster which supports the coach body is held in position longitudinally by the anchor links which are pinned to the bolster sides and the bogie transoms. One anchor link is provided on each side of the bolster diagonally across. The links can swivel universally to permit the bolster to rise and fall and sway sidewards. They are designed to take the draw and braking forces. The anchor links are fitted with silent block bushes.
3. Silent Block
This is synthetic rubber bush fitted in certain components of ICF/BEML bogies to facilitate adjustment and reduce noise.
4. Brake Rigging
The brake rigging has been arranged in such a way that the brake pressure is equally distributed over all the eight brake blocks. The brake beams are of welded design and on either ends fabricated brake block heads are provided. The brake beam is suspended by brake hangers pinned to the bogie head stock and transom. Removable brake blocks are mounted on the brake shoe by means of brake shoe keys. The renewal part of this arrangement is only the brake block made of cast iron. Adjustable palms have been provided to take up tyre wear and double acting automatic brake slack adjusters have been provided to take up brake block wear. The slack adjusters are mounted on the underframe.
5. Equalising Stays
This device has been provided on bogies between the lower spring plank and the bolster to prevent lateral thrust on the bolster spring as these springs have not been designed to take the lateral forces. These links are pin jointed at both ends and, therefore, move freely.
6. Swing Link
In the secondary suspension, the bolster is supported on helical spring which are placed in the lower spring plank. The lower spring plank is suspended from the bogie side frame with the help of four swiveling hangers on hanger blocks. The friction between these hangers and hanger blocks damps the bolster swing.
7. Shock Absorbers
Hydraulic shock absorbers offer resistance of ± 600 kg at a speed of 10 cm/sec. are fitted to work in parallel with the bolster springs to provide damping for vertical disturbance.
Primary and Secondary Springs
8. Schlieren Bogie
8.1 In this design, helical springs are used on the primary suspension and laminated spring on the secondary suspension. The coach body is supported on the centre pivot over the bolster, the two ends of which rest on the bolster laminated springs and these, in turn are suspended from the bogie frame by four swing links. The laminated springs are grease lubricated to maintain a more or less constant friction damping. Two anchor links diagonally arranged between the bolster and the bogie frame fix the bolster longitudinally in the frame ad transmit the tractive/braking force fromth coach underframe to the bogie. The bogie frame is supported by a pair of axle box springs at each axle box. The axles are provided with spherical roller bearing.
8.2 The primary suspension is similar to that of all coil ICF bogie where telescopic cylindrical guides immersed in oil and accommodate a simple hydraulic shock absorber consisting of a plate with a number of calibrated holes. The vertical oscillations of the coach are thus damped at both the primary and the secondary stages.
9. BEML Bogie (Man-Hal Version)
9.1 In this design, helical springs are used on both the primary and the secondary suspensions. The coach body is supported directly on two side bearer over the bolster springs which, in turn, are carried in a trough and suspended from the bogie frame by four 400 mm long links inclined at an angle of 6.5 deg. To the vertical. To keep the frictional forces at bearing surfaces low, the side cylinders in proportion to the reduction of pressure in the brake pipe.
9.2 Angle cock : These are provided on each end of the brake pipe and feed pipe and enable a coach to be isolated for the purposes of shunting, etc.
9.3 Hose coupling : Both the brake pipe and feed pipe are fitted to the angle cock outlet for through passage of compressed air from one coach to the other by means of braided rubber hose and meal couplings.
9.4 Auxiliary Reservoir : This is connected to the feed pipe and distributor valve and provides compressed air for filling the cylinder.
9.5 Guard’s van valve and pressure gauge : These are provided in the Guard’s compartment.
9.6 Isolating cock : It is a device used to isolate the air from one point of brake circuitary to other point. The handle of this cock is kept parallel to the pipe to indicate that it is in open condition.
9.7 Choke : It is a device for restricting the flow of air by limiting the size of the hole. It is provided in passenger emergency alarm valve and non return valve (provided in the feed pipe leading to auxiliary reservoir).
9.8 Passenger emergency : Alarm signal device (pilot valve) is fitted on the coach end wall of coach and is connected to alarm chain for actuating passenger emergency valve.
9.9 Passenger emergency alarm valve is located either on theunderframe or on end wall of coach and is connected t brake pipe for venting the brake pipe pressure to atmosphere.
9.10 Direct Collector : It is a device consisting of filter fitted in the pipe line of brake & feed pipes of the coach to separate dirt etc. from the air supply from locomotive/test rig.
3 Passenger Emergency Alarm System
3.1 As the name suggests, this system enables a passenger to indicate to the train driver the occurance of an emergency warranting thereby, the stoppage of train as well as identification of the coach in which emergency exists.
In brief the system consists of conventional alarm chain pulling arrangement having a clappet valve fitted with a cam and a multipoint limiting switch on every coach. Moreover, supply to the multipoint limiting switch is given from respective coach batteries and its contacts are connected to two indication lamps fitted on both sides of the coach at one end. In addition the contact of the limiting switch are also connected to electrical couplers at both end walls of the coach. Continuity of these electrical couplers from coach to coach and ultimately to locomotive is maintained by a set of wires. This system through internal wiring in the locomotive is also connected to a buzzer and indication lamps in the loco cabin. However, the power supply to locomotive circuit is provided from locomotive itself.
When alarms chain is pulled from a coach, rotation of the clappet valve rod, causes limiting switch from that coach to function, thereby switching ‘on’ the indication lamps. Simultaneously this action completes the circuit in the locomotives through inter coach wiring thereby operating the buzzer and indication lamp in the locomotive, thus conveying the emergency message in the locomotive. To avoid its misuse by miscreants, the arrangement has been designed in such a way that once the system is used, it can not be reset without the use of a special key kept with the train guard/driver.
Bogie Assembly :
16.1 General
Bogie assembly could be systematically carried out, if it is organized under three workstations described hereunder. A substore in the bogie shop may be necessary to ensure supply of proper components and subassemblies for bogie assembly.
16.2 Brake Gear And Axle Guide Assembly Work Station
16.2.1 After the inspection, repair and alignment of BSS brackets, axle guides and the bogie frame, place the bogie frame in the normal position on assembly stands.
16.2.2 Assemble the brake gear components including brake blocks on the bogie frame with pins, washers and split cotters. Ensure that the cotters are split minimum 450 and not slack in the pins. Modified lever hanger pins (RDSO sketch no. 93234 Alt.1) should be used to prevent the bush working out of the lever hanger. Ensure that the maximum clearance between the pins and bushes is 1.5 mm.
16.2.3 Apply some lubricating oil on axle guide outer surface and on inside surface of guide bush. Assemble the axle guide components on the axle guide and secure them with guide cap (whose 9 holes should be cleaned before securing) as per RDSO sketch no. 85070 Alt.3. While tightening the guide cap, it should be ensured that guide bush sits tight against the rubber packing ring and the holes in the guide are in alignment with corresponding holes in the guide bush. New coaches are fitted with modified axle guide arrangement to ICF/Sk – 0-1-182.
16.3 BOLSTER ASSEMBLY WORK STATION
16.3.1 Grease the BSS pins, hanger blocks, anchor link silent block pins and anchor link brackets with graphite grease. Ensure that bolster springs with height (under test load) variation within 2 mm are selected in the same group of springs for each bogie assembly.
16.3.2 Assemble lower spring planks, bolster spring, rubber washer, bolster springs and other secondary suspension components. Lower the bogie frame assembled with brake gear and axle guide assembly on the bolster assembly. Connect the bogie frame and lower spring plank with BSS hanger with the help of a dead weight. Connect the lower spring planks and bolster with equalizing stays and pins. Secure the equalizing stay pins with washers and split pins. Ensure that the split pins are split minimum 450 and not slack in the pins. Connect the bogie frame and bolster with anchor links. Secure the anchor links in the brackets with M 12 hexagonal head screws and spring washers.
16.3.3 Replace the rubber sealing cap on the centre pivot silent block. Assemble the lateral shock absorbers between bogie frame and bolster.
16.4 Bogie Lowering Work Station
16.4.1 Select the wheel sets such that the maximum variation in tread diameter between the wheels on same axle as 0.5 mm, between two wheel sets in the same bogie as 5 mm and among the four wheel sets in the same coach as 13 mm. Select axle box spring of 2 mm variation in height under test load in the same group of springs.
16.4.2 Assemble the lower rubber washer, lowering spring seat, compensating ring, wooden packing ring, selected axle box springs, upper spring seats, upper rupper washer, protective tube, etc., as per the drawing for axle box guide arrangement. Put dash pot oil of approved brand in lower spring seat to a level of 60 mm from bottom. The approved brands of dash pot oil are the following :
i. Servoline – 68
ii. Yantrol – 68
iii. Bharat univol – 68
16.4.3 For obtaining correct buffer height when the coach body is lowered on the bogies, while assembling the bogie, wooden packings of required thickness, depending on the wheel diameter, should be provided under the flanges of the lower spring seats. Where a wooden packing of 48 mm thickness is used, a steel ring should be welded at the bottom of the lower spring seat to increase the length of its projection below the flange of the spring seat, or another lower spring seat projection should be provided. Compensating ring of suitable thickness should be placed over the flange of the lower spring seat ensuring that the combined thickness of the compensating ring is limited to 12 + 2/-0 mm. the total thickness of the wooden packing and the compensating ring approximately equals the tread wear.
16.4.4 Lower the bogie frame with the bolster assembly on the wheel sets thus prepared, taking care to ensure that the rubber packing ring does not get damaged while lowering the guide bushes on to the lower spring seat. The maximum diametrical clearance between the lower spring seat and guide bush should not exceed 1.6 mm. the bogie should sit evenly on the four axle boxes.
16.4.5 The assembled bogie should be load tested on a bogie test stand where it is loaded up to its normal working load and the height of bolster top surface form rail level should be measured for comparison with pre-determined dimension corresponding to correct coach buffer height. Adjustment for getting correct buffer height should be made, if needed. If the buffer height requires further adjustment, the load on the axle box spring should be released and the packing rings in halves should be inserted below the axle box spring ensuring that the total combined thickness of all the compensating rings and packing rings under each spring do not exceed 20 mm.
16.4.6 Safety straps of the axle box wing lugs and bogie bolster should be adjusted so as to ensure a minimum clearance of 40 mm between the lugs and bottom of safety straps.
16.4.7 Fit the vertical shock absorber between the bolster and bottom spring plank.
16.4.8 Check the oil in the dash pots with the flexible wire gauge and if necessary, top up the dash pots with the approved brand of dash pot oil to bring the level to 60 under surface of dash pot. If the flexible gauge indicates a higher level of oil, the guide cap may have fallen in dash pot. This should be checked and attended to.
16.4.9 Axle box rubber bump stopper should be adjusted to obtain the required clearance between the axle box crown and the bogie frame.
LIFTING SHOP
17. Lowering the Coach Body
17.1 Place the wearing plate and wearing piece in side bearer well. Fill each side bearer well with 2 litres of any of the following approved brands of oils.
· Servoline – 68
· Yantrol – 68
· Bharat univol – 68
17.2 Apply graphite grease on Centre pivot in and lower the coach body on the side bearer wearing pieces. Care should be exercised to make sure that the side bearers are resting properly. Place the cotter in position and secure it with split pin. A bottom cover should be fitted for covering the entire assembly to prevent dust getting in. tighten the air vent bolt with gasket to prevent spilling of dash pot oil.
ANTI-COLLISION DEVICE (ACD)
RAKSHA KAVACH: - ‘‘RAKSHA KAVACH’’ IS A NETWORK OF “SELF ACTING” MICRO PROCESSOR BASED DATA COMMUICATON DEVICES CALLD ACDS WHICH “AUTOMATICALLY” APPLY BRAKES TO TRAINS THEREBY PROTECTING THE TRAVELLING PUBLIC AS WELL AS ROAD USERS AT LEAVEL CROSSING GATES FORM “COLLISION‘‘RELATED ACCIDENT.
Introduction to RAKSHA KAVACH:
RAKSHA- KAVACH tm (ACD System is a non- signaling network of anti-collision devices to prevent collisions between trains and between train’s vehicles in Indian Railways.
The ACD system provides capability to perform the following:-
Detection and Prevention of Head-on Collisions
Detection and Prevention of Rear-end Collisions
Detection and Prevention of side Collision in block sections in both directions.
Detection and Prevention of Collision due to fouling.
Detection of Train Parting / Jumbling and alerting approaching trains
Station approach warning for driver
Speed Limit Imposition
Approach Warning for Road Users
SOS Functionality.
WHATE ACD WILL NOT DO: -
i, It cannot prevent collision with non- ACD fitted trains.
ii, Any failure of ACD s within the system cease protection functionality until replacement/ restoration.
iii. I n case either ABU (Auto Braking Unit) has failed as isolate, the system cases it to cease protection functionality until replacement/restoration.
iv. Since ACD is dependent on trains braking, any brake failure of a train causes it to ceases protection functionality.
v. The ACD system depends on GPS system being available with accuracy of at least 25mts for correct determination of Track-ID. Any determination of wrong TID due to any error causes to cease protection functionality. However TID-FS mode still protects the ACD fitted trains.
vi. Only a portion of trains of 50 meters behind the guard van ACD is protected for prevention of collision due to fouling.
vii. Detection of parting is not possible when the guard van ACD is passing through GPS shadow Zone, or when a Guard van ACD is not attached to a loco ACD or the train length is not yet calculated.
ANTI-COLLISION DEVICE (ACD): - It is “Self-acting” microprocessor-based date communication equipment designed and developed by Kankan Railway. When installed on locomotives (along with Auto Breakings Units), Guard Vans/ SLRs, Station and Level Crossing gates (both manned as well as un-manned), the resultant “network” of ACD systems prevents “high speed” collision in mid-sections, Station area and at Level crossing gates, thereby saving the lives of passengers and road users. While entering the Station Area, if Loco ACD detects the presence of train standing or moving away on the main line, it ‘automatically’ regulate its train speed to what is maximum permitted over turnouts, thereby reducing possibility of ‘high-speed’ collision. Further if, Loco
ACD after entering in Station Area, detects presence of another approaching train on the same track, both Loco ACDs ‘automatically’ apply brakes to stop their respective trains.
While traveling in the Midsections, Loco ACDs remain in ‘look out’ for trains present in the radius of 3kms to handle following potentially dangerous ‘collision-like’ situations.
In case. Loco ACD detects that any other trains has stopped on adjacent track may be due derailment, Loco failure, cattle run-over, alarm chain-pulling etc. it will automatically regulate the speed of its trains till such time it crosses it and will also warn the driver of the same. If the driver of the stopped train presses ‘cancel’ button after ensuring that there is no danger to movement of trains on adjacent tracks and presses twin SOS (Save Our Soul) button, the other approaching trains will come to a stop, thereby reducing possibility of either ‘rear-end’ or ‘side’ collision
In case, a train detects another trains approaching it on the same track, the loco ACDs both the trains apply brakes to bring their trains to a STOP, thereby reducing possibility of ‘head on’ collision.
In case a train detects another train moving ahead of the same tracks, its loco ACD automatically applies the barkers to regular the train speed, till such the separation distance between the two stars ‘increasing’ again, thereby reducing possibility ‘rear-end’ collision.
In case a train while approaching a level crossing gate detects it in ‘opened’ condition, its loco ACD regulates the speed of its and warn the driver for talking a appropriate action, thereby reducing possibility of collisions of a train with road vehicle, crossing the LC gate.
Drivers to the train thereby gate “Door-deistic” (a 3 kilometers rang detection system in all weather condition, which a human eye is incapable of) through their loco ACDs to detect the presence of trains in their vicinity.
By acting independently the Loco ACDs also acts like “Seethe” companion for the drives, Further, in case a “collision-like” situation is perceived, the drives get empowerment to stop other approaching trains by seeding ‘DISTRESS’ messages through pressing of twin ‘SOS’ buttons, provided on their consoles.
The Guard ACD keeps monitoring the transmission of its Loco Acd & acts a stand – by protection to train if Loco ACD stops radiating. In the event of ‘Train Parting’ or “Rolling – Back”
In the mid-section (detected first by Guard ACD) both Loco and Guard Acds of the train shall radiate this information to prevent ‘rear-end’ and/or ‘side’ collisions o their trains that might have derailed and infringing the adjacent track.
This ‘Rakish Kavach also Empowers its other users to seen ‘SOS’ to LOC ACD s for stoppage of trains, whenever a ‘collision-like’ situation is perceived by them as under.
Guard can send manual ‘SOS’ through his guard ACD by pressing of twin SOS buttons when he observes dragging of derailed of derailed coaches/wagon close to his SLR/ Brake van or notices a Fire in the running train.
Station master can send manual ‘SOS’ through his station ACD by pressing of twin SOS buttons when he notices anything like hot axle/flat tare/fire etc. in a train, while performing train passing duties
TYPE OF ACD
1. Loco ACD
2. Guard ACD
3. Station ACD
4. Manned Gate ACD
5. Unmanned LCACD
6. TID Assigning ACD
7. Basher Line Loco Shed ACD
8. Repeater ACD
9. Unmanned ACD
I. ANTI-COLLISION DEVICE (ACD) :- It is “Self- acting” microprocessor – based data communication equipment designed and developed by Kankan Railway. When installed on locomotives (along with Auto-Braking Units), Guard Vans/ SL Rs, Station and Level Crossing gates (both manned as well as un- manned), the resultant “network” of ACD systems prevents “high speed ” collisions in mid-sections, Station area and at Level crossing gates, thereby saving the lives of passengers and road users. While entering the stat ion Area, if Loco ACD detects the presence of a train standing or moving away on the main line, it ‘automatically’ regulates its train speed to what is maximum permitted over turnouts, thereby reducing possibility of ‘high - speed’ collision. Further if, Loco ACD after entering in Station Area, detects presence of another approaching train on the same track, both Loco ACDs ‘automatically’ apply brakes to stop their respective train. While travelling in the Mid- Sections, Loco ACDs remain in ‘look out’ for train present in the radius of 3 kms to handle following potentially dangerous ‘collision-like’ situations.
II. The ACD system provides capability to perform the following:-
· Detection and prevention of Head – on Collision.
· Detection and Prevention of Rear-end Collisions
· Detection and Prevention of Side Collision in block sections in both directions.
· Detection and Prevention of Collision due to fouling.
· Detection of Train Parting / Jumbling and alerting approaching trains.
· Station approach warning for driver
· Speed Limit Imposition.
· Approach Warning for Road Users.
· SOS Functionality.
III.
v In case Loco ACD detects that any other train has stopped on adjacent track may be due derailment, Loco failure, cattle run- over, alarm chain- pulling etc. it will automatically regulate the speed of its train till such time it crosses it and will also warn the driver of the same. If the driver of the stopped train presses ‘Cancel’ button after ensuring that there is no danger to movement of trains on adjacent track and presses twin SOS (save our Soul) button, the other approaching trains will come to a stop, thereby reducing possibility of either ‘rear-end’ or ‘side’ collision.
v In case, a train detects another train approaching it on the same track, the loco ACDs of both the trains apply brakes to bring their respective trains to a STOP, thereby reducing possibility of ‘head on’ collision.
v In case a train detects another train moving ahead of it on the same track, its loco ACD automatically applies the brakes to regulate the train speed, till such time separation distance between the two starts ‘increasing’ again, thereby reducing possibility ‘rear-end’ collision.
v In case a train while approaching a level crossing gate detects it in ‘opened’ condition, its loco ACD regulates the speed of its train and warm the driver for taking appropriate action, thereby reducing possibility of collision of a train with road vehicle, crossing the LC gate.
Drivers to the train thereby gate “Door- drishti” through their loco ACDs to detect the presence of trains in their vicinity.
By acting independently’ the Loco ACDs also acts like ‘Saathi’ companion for the drivers. Further, in case a ‘Collision-like’ situation is perceived, the drivers get empowerment stop other approaching train by seding ‘DISTRESS’ messages through pressing of twin ‘SOS’ buttons, provided on their consoles.
The Guard ACD keeps monitoring the transmission of its Loco ACd & acts as a stand – by protection to train if Loco ACD stops radiating. In the event of ‘Train Parting’ or “Rolling- Back”.
In the mid-section (detected first by Guard ACD) both Loco and Guard ACds of the train shall radiate this information to prevent ‘rear-end’ and/ or ‘side’ collisions of train that might have derailed and infringing the adjacent track.
This ‘Raksha Kavach also Empowers its other users to send ‘SOS’ to Loo ACDs for stoppage of trains, whenever a ‘collision- like’ situation is perceived by them as under.
Guard can send manual ‘SOS’ through his guard ACD by pressing of twin SOS buttons when he observes dragging of derailed coaches/ wagons close to his SLR/ Brake van or notices a Fire in the running train.
Station master can send manual ‘SOS’ through his station ACD by pressing of twin SOS buttons when he notices anything unusual like hot axle/ flat tyre/ fire etc. in a train, while perfoming train passing duties.
LHB Coaches
Main features of LHB ( Linke Holfmann Busch) coach
Ø Higher carrying capacity as coach is 1.7 meter longer
Ø Better payload to Tare ratio
Ø Inter locked structural members
Ø Lesser chances of corrosion due to extensive use of stainless steel
Ø Low maintenance as replacement of most of the subsystems is expected only after one million kilometers.
Ø Minimum visibility of screws inside passenger compartments.
Ø Better passenger safety due to provision of emergency open able windows, CBC, Disc brake system, injury free features.
Ø Provision of CDTS.
Ø Mecor wood floor boards.
Ø Axle mounted Disc brake system.
Ø EUROFIMA type FIAT bogie.
Ø Weight per meter length of LHB coaches is approximately 10% less than the conventional coaches.
Ø No change required in shell design for speed of 200 kmph.
Dimensional Comparison
ICF LHB
1) Length over body: 21337 23540
2) Length over buffer: 22297 24700
3) Width over body: 3245 3240
4) Inner width: 3065 3120
5) Window opening ( AC sleeper) 1220*610 1180*760
Bogie frame:
The bogie frame is a solid welded frame made by steel sheets and forged or cast parts. The frame is made of two longitudinal components, connected by two cross beams which also support the brake units.
The various supports which connects the different bogie components are welded to the frame.
The bogie frame rests on the primary suspension spring units and supports the vehicle body by means of a bolster beam. The bolster beam is connected to the bogie frame by the secondary suspension.
MAINTENANCE INTERVAL
DESIGNATION
|
TYPE
|
KM.
INTERVAL
|
TIME INTERVAL
|
‘T’
|
---------
|
Trip Schedule
| |
‘W’
|
10,000 Km
|
Weekly
| |
‘NS’
|
40,000 Km
|
Monthly
| |
No. 1 Examination
|
F1
|
250,000 Km
|
6 Monthly
|
No. 2 Examination
|
F2
|
500,000 Km
|
Annually
|
Overhaul-1
|
R1
|
1,000,000 Km
|
Every 2 years
|
Overhaul-2
|
R2
|
2,000,ooo Km
|
Every 4 years
|
TECHNICAL DATA
DESIGNATION VALUE
§ TRACK GAUGE 1676 mm
§ Min Radius of Curves 175 mm
§ Speed Max. 180 km/h
§ Length of Car Body 23540 mm
§ Width of Car Body 3240 mm
§ Car Height above top of Rail 4039 mm
§ Wheels mono bloc 915mm
§ Distance between centre pivot 14900mm
§ Weight-coach weight (2 class) ca 39500 kg
§ No of Toilets 4
§ No of BERTH ( 1st class) 24
§ ,, ,, ,, ( 2nd Class II TIER) 52
§ ,, ,, ,, (2nd class III TIER) 72
§ Wheel Base 2560 mm
About Design & System
Bogies:-
Broad Gauge Bogie from FIAT/ SIG based on the EURO FIMA concept.
§ Bogie Frame:-
The Bogie frame is solid welded frame made by Steel Sheets and forged or cast parts. The frame is made up of two longitudinal components connected by two cross beams which also support the brake units. The bogie frame rests on the primary suspension spring units and supports the vehicles body by means of a bolster beam.
The bolster beam is connected to the bogie frame by the secondary suspension.
§ Axles:-
On the bogie each axle is fitted with two brake discs. Diameter 640 mm and width 110 mm. The brake discs are fitted on the wheels.
§ Axle Bearings:-
Axle bearings belongs to the TIMKEN type, a tapper roller catridge type bearing is used and it makes up a pre assembled munit not requiring any further intervention such as clearance adjustments. The axle bearings on the bogie are fitted with sensors for detecting speed (Wjhose signal is elaborated by anti sleeping system) and a current return device.
The ends of the control arms are fitted with centering devices for the primery suspension spring assembly. The bearing lubricating plug is fitted in the lower part.
§ CENTRE BUFFER COUPLER:-
1) LHB Coaches have been provided with tight lock center buffer couplers instead of Screw coupling.
2) Couplers are AAR H-Type and have anti climbing features because of vertical inter locking.
3) Couplers have adequate strength for the following:-
Satisfactory hauling of a train of 26 coaches at 110 kmph.
Satisfactory hauling of a coach of 18 coaches at 160 kmph.
§ BRAKE
Compressed Air brake system with disc brake equipments combined in a large extent in a container electro- pneumatic brake control, brake accelerator, micro processor controlled anti skid device. Hand brake working on two brake discs of one bogie.
§ DISC BRAKE SYSTEM
1) Axle mounted Disc brake.
2) Two Disc per Axle of dia 640 mm
3) In built slack adjuster in Brake cylinders.
4) 35 mm brake pads.
§ PRIMARY SUSPENSION
1) 2 Coil springs, one vertical damper, articulated controlled arm. Elastic joints connecting the axle bearing to the frame.
2) Better curve negotiation.
§ SECONDARY SUSPENSION
1) Nest of flexible springs inner and outer, Rubber spring and secondary pads,
2) Vertical Dampers, 3) Lateral Dampers, 4) Yaw Dampers, 5) Anti Roll-bar,
6) Anchor links.
§ ANTI ROLL-BAR
A torsion bar having two forks is provided between bogie frame transverses beam with the help of two links to resists rolling motion of coach.
§ BUFFER HEIGHT ADJUSTMENT
1) By adding or removing shims from body/ bogie connection.
2) Shims will not be added/ removed in primary and secondary suspension for wheel wear compensation of buffer height adjustment.
§ AXLE MOUNTED DISC BRQAKE SYSTEM.
MAIN COMPONENTS.
1) Control panel.
2) Bogie Equipments.
3) Anti skid system.
4) Flex ball cable arrangement (for parking brakes)
( Used only generator and SLR coaches)
§ Control panel consists of:-
1) Distributor valve with suitable relay valves and EP 2 ( optional)
2) Control Reservoir ( 6 lits)
3) Air reservoir-2 nos. ( 125 lits for A/Brake & 75 lits for Toilet)
4) Stop cock----2 nos (for Bogie isolation)
5) Isolation cock----2 nos ( for FP & toilet circuits)
6) Filter ( Dirt collector)-----2 nos.
7) Check valve.
8) Test fitting-------4 nos ( BP, FP, BC, & CR)
9) Pressure Switch.
§ Bogie equipment consists of:-
1) Brake Disc ( 2 per axle)
2) Brake caliper unit comprising of:- a) Brake cylinder.
b) Brake caliper.
c) Brake pads.
3) Indicators ( 4 nos per coach ) & 2 nos extra for GEN & SLR coach.
4) Emergency brake accelerators with cock (1 no. each per coach).
5) Emergency brake cable pull box ( As per requirements of the coach).
6) Emergency brake valve ( 1 no each per coach).
7) Angle cock ( 8 nos per coach).
8) Brake hose coupling ( 4 nos FP, 4 nos BP eqach per coach.)
§ Traction Center:-
The Traction center transmits friction and breaking forces between bogie frame and body by a traction lever, on the bolster beam pin and two rods.
The traction lever is connected to the bolster beam by means of a rubber bush, two plates and screws, while rods are connected to the bogie frame and to the traction lever by elastic joints and screws.
§ Principle of force transmission:-
Forces concerning the bogie are transmitted as follows:-
VERTICAL FORCES:-
From the body to the bogie frame trough the secondary suspension springs, from the bogie frame to the axles through the primary suspension springs and frame-axle bearing control arm.
CROSSWISE FORCES:-
From the body to the bogie frame trough the secondary suspension springs, from the bogie frame to the axle through the elastic elements of the frame-axle bearing control arm.
§ CURVE NEGOTIATION:-
An articulated control arm is connecting axle bearing and side frame trough elastic connection, which will provide flexibility between axle and side frame.
§ SPEED LIMIT:-
1) Up to 160 kmph without any modification.
2) Up to 200 kmph with minor modification.
§ WHEEL AND AXLE:-
1) 2 Brake discs (4), Diameter 640 mm & width 110 mm.
2) In built slack adjusting brake cylinder fitted.
3) 2 wheel disc of trad dia 915 mm ( new), 845 mm 9 worn).
§ AXLE BEARINGS:-
1) Taper roll cartridge type bearing.
2) Pre assembled unit.
3) Maintenance free overhaul 1.2 million km.
4) Sensors for detecting speed.
GENERATOR COACH
The generator cum brake van is commonly designed and manufactured by Rail Coach Factory, Kapurthala/ India and Alstom LHB, Gmbh, Salzgitter/ Germany.
The car shell is a steel light weight construction made from low corrosive and stainless steels meeting all static and dynamic operational requirements as well as considering the extreme environmental conditions.
The automatic Aar-type H “Tight lock” center buffer couplers offer a maximum safety for the passengers and the crew due to their anti climbing features and enable the combination of the cars to trains in no time. In addition side buffers are provided at each car end.
Technical Data
§ Max speed- 160 km.
§ Bogies- FIAT/ SIG ( EUROFIMA concept)
§ Coach weight- 51,000 kg.
§ Crew- 1 Guard, 5 staff
§ Power supply capacity- 28*300 kw by two diesel alternator sets
END WALLS
The car ends are provided with the following components:
§ AAR Type M-coupler
§ UIC Inter communication gang way
§ Side Buffer
§ Train line Coupler
§ UIC control coupler
§ Trail light ( only car end 2)
§ Tail lamp bracket.
WHEEL SLIDE PROTECTION SYSTEM (WSP SYSTEM)
(SAB WABCO KP BRAKE SYSTEM)
(SAB WABCO KP BRAKE SYSTEM)
During a constant braking force application, dependent upon the coefficient of friction available at the wheel/rail interface, the wheel sets could start to slide. Sliding causes damage to the wheel sets (flats) and increase the stopping distance. To avoid this the electronically controlled WSP system is used.
OVERVIEW
Axle speed of rotation is measured and evaluated separately within a speed range of 2 to 400 kmph. Axle speeds are compared with a reference speed which is calculated value basing on the real axle speeds. The comparison between these speed signals determines whether or not an axle is about to entering to a slide mode. The axle speeds are measured via speed sensors and phonic wheels, all located at the axle ends.
Solenoid valves (Dump valves) are connected to the brake piping close to the brake cylinders but mounted on the underside of the car body. These valves controls the increase and decrease of the air pressure in the brake cylinders to assure the optimum pressure in the brake cylinders and maximized braking for the prevailing wheel/ rail interface conditions, and thus prevent sliding from occurring.
AXLE MOUNTED DISC BRAKE SYSTEM
Special features:-
The equipment of the entire brake system in the LHB coach comes under a broad classification as detailed below:-
a) Brake frame control equipment
b) Brake control equipment in the system layout
c) Disc brake equipment on the bogie.
d) Wheel slide protection equipment (device).
The basic system of twin pipe graduated release air brake confirming to RDSO with 25 mm bore dia of BP/FP at 5 & 6 kgs operating pressure respectively in the use of passenger coaches. Another set of BP/FP branch pipes are also provided in each coach on the either side of central draw bar with BP, FP end cocks and hose couplings to provide straight connections of hose coupling set during the reversal and attachment of the coaches to the formation.
DETAILS OF SOPHISTICATION ADDITIONALLY PROVIDED ON LHB COACH BRAKE SYSTEM.
§ A Brake panel with aluminum panel manifold accommodates the critical valves of the brake system. It also contains the test points checking the pressure of BP, AR, DV, BC, and CR outputs at one location itself.
§ The C3W IP DV incorporates additionally a relay valve which ensures consistent application and release timings of brake.
§ A brake pipe accelerator valve with an isolating cock is connected to the brake pipe of the vehicle that provides rapid venting of the brake pipe air. It comes to action during brake applications whenever the BP pressure is exhausted at an emergency rate and does not get activated during normal service braking function up to full service position of the drivers brake valve.
§ Pilot valve for passenger emergency is provided inside the coach to enable a passenger for operation with a pull for stopping the train in case of an emergency.
§ A Disc brake is mounted at each axle at outer ends with the wheels instead of the conventional system of brake at wheel treads.
§ UIC pattern twin brake indicators are provided on each side of the coach that gives a visible display of the condition of brakes on each bogie.
§ Wheel Slide Protection Electronic Rack version enables the braking system to be operated at each optimum performance level by maximizing the use of available adhesion during braking of the train.
§ Load proportionate braking system that influences the BC pressure output by modulating the brake cylinder pressure proportional to the load being carried.
PRINCIPLES OF OPERATION OF BRAKE SYSTEM
When the twin pipe system with BP & FP lines on the coaches of the train is charged 5 & 6 kg/s respectively by the locomotive, the air pressure in the air brake pipe connected to the distributor valves, controls the brake system of the coaches.
To initiate and effect a brake application, the air pressure in the air brake pipeis reduced and the distributor valve in each coach reacts to supply the auxiliary reservoir air pressure at a pr4oportionate level as BC pressure to the actuatorsThis BC pressure acts as a signal pressure to the large capacity relay valve. The relay valve in turn quickly supplies air pressure of the same intensity to the four wheel slide valves and finally to the two brake actuators provided one for each brake disc.
The force developed in each brake cylinder causes piston movement and subsequently through linkage passeson its Brake caliper with pads to close on the individual brake disc provided on each wheel set. The binding causes friction and retardation to wheel rotation The force applied on mthe disc and the effect will be proportional to the BC pressure supplied to the brake cylinder.
If wheel slip occurs on any wheel consequent to the brake force from the disc not having been absorbed due to insufficient wheel/ rail adhesion factors, a sensor provided in axle end cover and phonic wheel fitted on one end axle end of each
wheel in combination feeds the signal to wheel slide protection unit to automatically stop the wheel slide.
Reduction in the brake pipe air pressure can be caused by any one of the operations/ events as under:-
a) Driver’s Automatic Brake valve on the locomotive.
b) Guard’s Brake control in Brake Van.
c) Plot valve for passenger Emergency.
d) Parting of train and disengagement of brake pipe.
Of these, in respect of Driver’s Automatic valve operation only, it can provide a graduated brake application or release. For any brake pipe pressure held steadily below the normal running regime pressure of 5kg/s, a brake application by way of brake cylinder pressure build up will be caused by the DV and will be held steadily at the proportionate level against normal leakage in the system.
Periodical examination and testing of alarm chain apparatus.
Periodical examination of the alarm signal apparatus for each coach should be carried out once in every three months at the primary maintenance depot in the following manner.
The moving parts and the spring in clappet valve assembly should be cleaned and greased.
The rubber washer in the clappet valve should be renewed, if necessary, and kept free from grease and grit.
When the clappet valve and the rod are in the normal position, the chain should be examined to ensure that it does not drop in any of compartment opening and where this occurs, the chain should be cut and adjusted.
When the chain is pulled, it should be ensured that the cam opens the clappet valve sufficiently; otherwise it should be suitably adjusted.
For further details of periodical examination and testing of alarm chain apparatus, reference may be made to paragraph 2.9.9, Chapter 7 of Part II.
Date and station code of the depot should be stenciled at the appropriate place in Schedule maintenance Chart on the end panel after every periodical examination.
Testing of air brake system:
Air brake system of rakes and sectional/ spare coaches should be tested at primary/ secondary maintenance depots with the use of compressor or locomotives in the manner prescribed in sub-sequent paragraphs.
Procedure for testing of the full rank:
The following tests are to be conducted in every round trip of the rank:-
(i) Visual inspection: This is to check for any damage on the brake or feed pipe, hose coupling, etc. The suspension brackets and anti- pilferage devices of all air brake equipments shall also be checked at the same time. Any defect noticed shall be attended to.
(ii) Leakage test for brake pipe and feed pipe and its branch pipes connecting equipments.
(iii) Service application and released test.
The tests mentioned at and can be done simultaneously. For this, the following procedure shall be followed:
Connect the brake pipe and feed pipe of the test rig to the brake pipe and feed pipe first coach of the rake though hose coupling.
Charge the system with compressed air to the full pressure of 5 kg/ cm2 for brake pipe and 6 kg/cm2 for feed pipe and stabilize for approximately 270 + /- 30 seconds.
Cut off the supply of compressed air by operating isolating cock for brake pipe and feed pipe of the test rig.
Watch the drop in pressure due to leakage of more than 0.2 kg/cm2 per minute indicates that there is leakage in the system.
If there is leakage in the system, the coaches should be examined with the use of soap water and listening for hissing sound and the coaches having leakages identified.
After attending to the leakages and charging the system to the required air pressure, open the isolating cock for brake pipe and feed pipe of the test rig and make a full service application of brakes by reducing the brake pipe pressure by 1.5 kg/ cm2.
Simultaneously the piston strokes of brake cylinders of all the coaches of the rake shall be checked. The pistons should be in applied position. The piston stroke shall be recorded.
Then release the brakes by recharging the brake pipe to kg/cm2.
On releasing the brakes, the pistons of all the brake cylinders should come to release position and the brakes in fully released condition.
If not, the defect should be identified and rectified by repair or replacement of defective components.
Procedure for testing single coach:
Where it is necessary to identify the defect in individual coach or where the air brake coach has been attended to for a brake related defect, the individual coach shall be tested as per the following procedure:
Connect BP and FP of Test coach to BP and FP of Test rig keeping the other end of BP & FP on the Test Coach closed.
Charge BP at 5 kg/ cm2 & FP at 6 kg/ cm2 respectively for 15 minutes and stabilize.
Make a pressure drop of 0.4 kg/ cm2 in 6 seconds for sensitivity test & 3.5 kg/cm2 for service and emergency applications respectively.
Ensure that all the brakes blocks are on applied position with the piston travel of 50 to 100 mm.
Charge the system again with 5 kg/ cm2. It should be observed that the piston return to the original position & brakes released.
In all the above tests, the control of dimension ‘A’ of slack adjuster shall be kept as 22+ 4 mm.
Procedure for testing of individual assembly:
Where an individual subassembly like distributor valve, angle cock, reservoir valve, etc., has been repaired, that particular subassembly shall be tested by testing the coach fitted with the subassembly on the single coach test rig as per procedure detailed.
Procedure for testing the emergency valve:
Charge the brake pipe 5 kg/cm2 and feed pipe with 6 kg/cm2.
Pull alarm chain one at a time.
Check the working of Emergency Alarm Signal Equipment (pilot valve) fited on the end wall and passenger emergency valve fitted in the underframe of the coach. Hissing sound should come from these equipments due to brake cylinder piston of the coach.
Reset the disc of pilot valve with the help of the coach.
Reset the disc of pilot valve with the help of the key to
After the resetting with the help of key, the exhaust of air from pilot valve and actuating valve should stop. If it does not stop then passenger emergency valve should be opened, cleaned for dust and refitted or the same may be replaced by a new valve.
The above tests are to be done for each coach of the rank.
Procedure for testing the Guard Van Valve:
Charge the system with 5 kg/ cm2 in BP and 6 kg/ cm2 in FP.
Record the pressure in Guard’s pressure gauge.
Watch the pressure in the Guard’s Van Valve and see that this should not exceed by 0.2 kg/cm2 of the pressure in the test rig/ loco. Rectify the leakage if exists.
Operate the handle of the guard’s van valve and ensure its smooth working.
Watch the exhaust of air through the vent of the Guard’s Van Valve by hissing sound.
Watch the moment of brake cylinder piston of this coach.
All the brake vans of the rake should be tested individually.
CHAPTER TWO: SICK-LINE
RELEASING PROCEDURE OF BRAKE BINDING (BOGIE MOUNTED STOCK)
Condition:- Only one cylinder not releasing
Remedy;- 1. Isolate BC
Piston releases
Close the BC Isolating cock and work up to destination
2. If piston does not release
Insert a Tommy bar between truss beam and wheel flange and give a jerk.
Piston releases
Close the BC Isolating cock and work up to destination.
3. If piston still does not release
Pull the ring of the locking pin of the sleeve
Turn the sleeve clockwise
After the brake blocks loose their grip on the wheel tread knock out the pin connecting the equalizing lever with the piston.
Close the BC Isolating cock and work up to destination.
Condition:- Both Trolleys affected
Remedy:- 1. Pull the QRV of DV
Piston release
Close the BC & DV Isolating cocks and work the train up to destination
2. If piston still do not release
Isolate BCs
Pistons release
Work the train up to destination
3. If pistons still do not release
Close isolating cocks of AR & DV
Pull QRV lever again
Piston release
Isolate BCs & DV
Work the train up to destination
4. If pistons still do not release
Open AR drain cock.
Pistons release
Isolate BCs & DV
Work the train up to destination
5. If piston still do not release
Slacken flexible hose coupling
Isolate BCs keeping the locking pin pulled with the help of the ring, turn the sleeves of the cylinders clockwise
Brake blocks loosen their grip from the wheel tread
Pistons release
Work the train up to destination
RELEASING PROCEDURE OF
BRAKE BINDING (UNDERFRAME MOUNTED STOCK)
Condition: -. Only one trolley affected
Remedy:- 1. Brake binding occurs with brake cylinder in released condition
Rotate SAB anticlockwise (SAB rotating)
Release Brakes by rotating SAB
Isolate BC
Work the train up to destination
2. Brake binding occurs with brake cylinder in released condition
Rotate SAB anticlockwise (SAB stuck up)
Release brake rigging by removing palm end pin
Isolate BC
Work the train up to destination
3. Brake binding occurs with brake cylinder in applied condition
Operate QRV of DV
If BC is released isolate BC by closing IC
Work the train up destination
4. Brake binding occurs with brake cylinder in applied condition
Operate QRV of DV
If BC does not release isolated condition
Work the train up to destination
If piston does not release isolate BC and open BC drain plug
Work the train up to destination
Condition:- Both Trolleys affected
Remedy:- 1. Release DV
If pistons release isolate BCs & DV
Work the train up to destination
2. Release DV
If pistn do not release isolate AR & DV
Pull QRV lever again
If pistons release
Leave DV in isolated condition
Work the train up to destination
3. Release DV
If pistons do not release
Open AR drain cock
Pistons release
Isolate BCs
Work the train up to destination
If pistons do not release
Isolate both BCs
Remove both BC drain plugs & restore after pistons release
Or Slacken flange nuts of IC
Work the train up to destination
CHAPTER THREE: TRAIN PASSING
Train passing: This is yet another very important aspect which runs hand in hand with the various schedules of maintenance(schedule A, B, C,IOH, POH,etc. as explained earlier) for the effective and safe running of the number of trains in operation. In other words, train passing is the last foothold in the hierarchal demarcation of maintenance and operation for the various operating rakes as used by the Indian Railway Industry.
It has to be performed both after the primary as well as the secondary maintenance chores before the train enters the station and leaves as well.
Rollin and Roll out: These are the activities which are mandatorily performed when the train enters or leaves the station respectively. It demands an effective use of the sense organs (esp. eyes for finding out any unwanted hanging parts or decoupled parts, ears for any kind of unusual sound, nose to sniff out the presence of any burning smell that might originate due to the overheating of the axle box bearing, etc.). The concerned workers wait at definite sites before the train enters or leaves the station to maneuver their jobs effectively.
The period of time for which the train remains in the station before departure undergoes a few last activities of maintenance. They are:
1. Any defective air hose pipe is identified and thus replaced
2. Coupling of any decoupled hose pipe is done
3. Out of the various wheel defects (as explained earlier), if any case of flat tyre is identified then it is corrected by grinding, etc.
4. Laser gun is an important tool nowadays. As shown below, it is a small device which can be held in the hand by the concerned personnel and temperature of the axle box is measured. A laser beam is sent out and is made to fall on the axle box cover plate. The mechanism inside the laser gun picks the temperature of the axle box and flashes it on the screen of the laser gun. Any axle box with a reading below 60°C is considered safe for passing, otherise not. Thus, generation of fire during running of trains due to bearing overheating is prevented and thus it is the most important aspect in train passing.
Bypassing: this is one of the various reparative measures undertaken in case of a brake pipe (BP) failure of a single coach. During journey, if any pipe shows leakage it cannot be changed before reaching the station. In that case, angle cocks at both the ends of the faulty BP are closed. The end of the BP at the start of the coach is connected to the feed pipe (FP) with the help of a bypass device. Air now flows through the FP. Again at the other end of the coach, the FP is connected to the BP with the help of a bypass device. When this system is used then only one pipe operation occurs at the concerned coach. The bypass device used to connect the opposite palm ends of the BP and FP is shown below.
As all the activities mentioned above are performed satisfactorily, the authority at the station issue a certificate to the guard of the concerned rake declaring it to be safe to pass and start its journey. The certificate is shown below.
jon said...
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