LHB – COACHES
3.1 Introduction to LHB Coaches
(Linke Hoffmann Busch GMBH – German)
Indian railways have been manufacturing passenger coaches of “Schlirien” design for more than 50 years. Although continuous efforts were being put to upgrade these coaches, due to constraints/limitations in the design, we could not cope up with quality and speed of the Railway transport in the developed countries.
It was felt to imbibe technology in-use, in the developed countries so as to affect a quantum jump in quality and speed of Railway coaches.
“M/s Alstom and Linke Holfmann Busch (LHB)” are one of the leading manufacturers in transport sector having presence in most of the European countries. Coaches manufactured by them are running in many countries across the world.
LHB coach body is designed and manufactured by leading German company Linke Holfmann Busch GMBH and Bogies for these coaches is designed and made by M/s FIAT, Switzerland which is now a part of Alstom group. Indian Railways entered into a TOT agreement with M/s. Alstom Germany for manufacture of LHB type of Coaches. Accordingly, their inception and mass production in Railways started in 2002 and population is growing day by day.
3.1.1 BENEFITS TO RAILWAYS
- A longer coach: LHB coaches are approximately 1.7 meters longer than the conventional ICF type coaches. This means “more travel space”, “increased seating capacity”, “wider bays and doorways” etc.
- A lighter coach: Weight per meter length of LHB coach is approximately “10%” lesser than the conventional coach. This not only means lower haulage costs but also less wear and tears of the coaches and track.
- A higher speed coach: LHB coaches are designed to run at a maximum speed of 180 kmph. Even for speeds of 200 kmph, no major changes are required.
- Lesser maintenance required: Lesser maintenance required due to Use of superior materials with longer life.
- Wheel slide protection (WSP) system based on microprocessor: It detects the variation of speed between the 4 wheels of the coach and if any wheel is rotating at a lower speed, the particular wheel brake is released automatically. This protects the wheel from skidding.
- Bogie with less moving parts.
- Items of wear & tear do not require replacement/renewal before 10 lakh km.
- Entrance doors flush with side wall allowing automatic car washing.
3.1.2 BENEFITS TO THE PASSENGER
- Better ride quality: With improved ride comfort – ride index reduced from over 3.0 to 2.5 at a speed of 160 kmph.
- Plush interiors comparable to international standards.
- Improved air-conditioning through better duct designing & humidity control.
- Bigger size sealed windows filled with “argon” gas for a panoramic view & better heat insulation.
- Modular “oriental” & “western” style toilets with Controlled discharge toilet system (CDTS) This system works on electro- pneumatic principle where in, the waste generated from the coach lavatories during run is collected in a retention tank and is disposed off away from the station limits and avoid soiling of station premises.
- Well equipped pantry with hot cases, deep freezer, bottle coolers etc.
- Flush type swiveling berth reading light.
- Polycarbonate transparent centre tables.
3.1.3 SAFETY RELATED PROVISIONS:
- Four emergency exit windows for faster passenger evacuation during emergencies.
- Wider vestibule designs for smooth inter coach movement with luggage.
- Convenient to operate emergency alarm pull operation and Fire – retardant furnishing controls the spreading of fire and prevents higher damages.
- Tight lock centre buffer coupler gives anti-climbing feature, during accident, leading to lesser injury to the occupants of the coach.
3.2 SALIENT FEATURES OF LHB COACHES
These coaches are longer by 1.7 meters than the ICF coaches and hence more number of passengers can be accommodated in a given coach. As the length of the coach is longer the number of coaches required to form a formation is reduced and hence overall cost of maintenance becomes less.
These coaches are fitted with Axle Mounted Disc brakes to have an effective brake power to stop the train within the short braking distance. As the brake forces are acting on the Discs which are mounted on the Axles, the wear on the wheel tread caused due to brake application on tread is eliminated and hence the life of the wheels are considerably increased.
These coaches are fitted with Wheel slide protection device to prevent the wheel from getting skid. Due to various reasons it is possible for any one of the wheel to have lesser speed when compared to the other three wheels and in such a case it releases the air from the brake cylinder of the affected wheel automatically to prevent the wheels from getting skid.
These coaches are fitted with Brake accelerator in the Brake pipe to bring BP pressure to zero during emergency brake application. The brake accelerator connects the Brake pipe with exhaust during emergency application to facilitate faster exhaust of air from the brake pipe.
These coaches are provided with FIAT bogies, which are designed to run at a speed of 160 KMPH. The wheelbase of Bogie is 2560 mm.
These coaches are fitted with earthing device to prevent damages to the Roller bearings. These coaches are fitted with roof mounted AC package units.
These coaches are fitted with Controlled discharge Toilet system designed to discharge the human waste when the speed 125 reaches above 30 KMPH. The objective of this toilet system is to keep the station premises clean and hygienic.
These are fitted with tight lock AAR centre buffer coupler with anti-climbing feature to prevent the climbing of one coach over another in case of accidents.
The following equipments are operated by Microprocessor controlled system
- Wheel slide protection device.
- Controlled discharge toilet system.
- Water pumping device.
- Roof mounted AC package units
The riding index of LHB coach is 2.75 when compared to 3.25 in case of ICF Coaches.
Up-graded design for passenger safety/comfort like; Ergonomically designed seats as per Indian anthropometrics data, 126 Large windows with good visibility, Luggage racks with in-built reading lamps, Insulation against noise, No visible screws in the interior. Use of fire retardant materials, Hand – safe feature in all automatic sliding doors, Anti – skid PVC flooring, UIC vestibules and auto – closing vestibule door.
Functionally designed pantry area is easily accessible AC unit controls. The passenger emergency alarms signal devices (emergency alarm pull box) are provided inside passenger compartment. This is to avoid operation of PEASD by unauthorized persons from outside. There is no mechanical linkage like a chain and this handle directly operates the PEA valve for venting the brake pipe pressure.
DESIGN FEATURES OF LHB COACHES
3.3 COACH SHELL
The entire shell is made from stainless steel and low corrosion steel. All the structural elements with section thickness above 5mm and more are made from Corten steel. Trough floor and roof panels are made from Austenitic stainless steel. Other structural members and side members and sidewall panels are made from ferritic stainless steel. The shell design eliminates turnunder and other pockets causing corrosion in conventional coaches.
Special Design feature of LHB coach flooring:
16 mm composite board made from cork panels glued to “Makore” wood has been used. Flooring panels are lightweight, strong, warp resistant and also resistant to vibrant/impact forces. These floors are specially treated for fire resistance; these are also resistant to moisture, cigarette burns, staining, aging etc. The intermediate cork layer imparts nice insulation characteristics to the floor panel. The “floating” floor is supported by rubber- metal decoupling elements, for absorption of structural vibrations. Interlocking joints of vertical & horizontal members is adopted for structural joints
3.4 FIAT BOGIE.
The LHB coaches are provided with the FIAT bogies to run at a speed of 160 KMPH.
Limitations of ICF all Coil Bogie
- The longitudinal and lateral movements of the wheels cannot be controlled independently as generally required for Highspeed bogies.
- Since there is vertical space constraint between the top and bottom bolster, it is not possible to provide softer secondary suspension springs which are required for the high speed trains to control the dynamic movements of the bogie bolster and coach body.
- Headstocks increase the yaw inertia of the bogie frame and thereby, influence the tendency for hunting. The wheelbase of ICF all coil bogie is 2896 mm. This large wheelbase affects curve negotiations and thereby increases wheel flange wear. 131
- Since the brake forces are offered on the wheel tread by clasp brake, it could not give sufficient retardation during brake application which in turn increases the emergency braking distances. The life of the wheel is also reduced due to tread wear.
3.4.1 FIAT BOGIE PARTS
- Design obtained from M/S Alstom-LHB, Germany as part of LHB-TOT contract
- Adapted at RCF for various coach variants
- Fit to run up to 180 kmph
- Superior ride quality
- Bump stops in primary and secondary suspension
- Miner pads in secondary suspension
- Yaw, lateral and vertical dampers
- Nested spring sets with 2 helical and one rubber spring in secondary
- Less wear and tear
3.4.2 BOGIE FRAME
- Solid welded frame -steel sheets (ST-52) and forged, steel cast parts to material GS20MN5V; DIN 17182 (weld able).
- Two side frames connected by two cross beams -support brake units various brackets on 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 secondary suspension.
Primary suspension
- Two coil springs, one vertical damper, articulated control arm, elastic joints connecting the axle bearing to the bogie frame
- Better curve negotiation.
3.5 Wheel and Axles
- Two brake disks (4), diameter 640 mm and width 110 mm.
- Two wheel disc of tread dia 915 (New), 845 (worn)
- Dynamic balancing 320rpm
- Less that/equal to 50gm.m
- Glue the needed weights.
AXLE BEARINGS
- Taper roller cartridge type bearing
- Pre-assembled unit.
- Maintenance free- overhaul 1.2 million km.
- Sensors for detecting speed
DISC BRAKE SYSTEM
- Axle mounted disc brake
- Two discs per axle of dia640
- Inbuilt slack adjuster in brake cylinders
- 35mm brake pads
SECONDARY SUSPENSION
- Nest of flexi-coil springs inner and outer, rubber spring and secondary pad
- Vertical dampers
- Lateral dampers
- Yaw dampers
- Anti-roll bar
- Anchor Links
PRINCIPLES OF FORCE TRANSMISSION
- Vertical forces: Body-secondary springs-bogie frameprimary springs/ball joint control arm-axles.
- Lateral forces: Body-Secondary Springs-Bogie Frame-Ball Joint Control Arm-Axles.
- Longitudinal traction efforts and braking powers: BodyTraction Centre-Traction Rods-Traction Lever-Bogie Frame-Control Arm-Axles.
Curve Negotiation: An Articulated Control Arm (SGCI TO IS:1865) Is Connecting Axle Bearing And Side Frame Through Elastic Connection, Which Will Provide Flexibility Between Axle And Side Frame.
Fiat Bogie Frame Fabrication: Sequence of Operations.
- Stage- i: Fitting of top flange, bottom flange, web and 6 ribs.
- Stage-ii: Fitting of control arm bracket, inside stiffener, brake head bracket, bkt for vertical damper.
- Stage iii: Robotic welding of above items.(mfr. M/S IGM ROBOTER system as Austria)
- Stage iv: Yaw damper assembly Bkt. & curve roll link Bkt. Tacking.
- Stage v: Full welding of bogie frame on manipulator.
- Stage vi: Flame straightening of side frame.
3.5.1 SALIANT FEATURES:
Speed limit: Up to 160KMPH without any modification & up to 200KMPH with minor modification
Riding index for Chair car: VERTICAL – 2.75 & LATERAL – 2.5
Comparison of salient features of fiat bogie against I.C.F. Bogie
3.5.2 Wheel Slide Protection device:
In LHB coach pneumatically controlled Disc brake system is used. During brake application, factors like variation of co-efficient of friction (due to composition of brake pads and disc) and adhesion between rail and wheels and various other factors may cause difference in RPM (rotation per minute) of axles on the same coach. This may lead to wheel skidding/ flat tyres. To prevent this, a Wheel Slide Protection (WSP) device is provided in these coaches.
3.5.3 Main Components and their functions:
Principle of working: The rotation of each axle is constantly measured and compared with a reference speed (The RPM of the fastest wheel of the coach) for that coach. In case there is a variation in RPM among the wheels, WSP automatically releases the brakes of the wheel with slower speed accordingly, so that the RPM of all the wheels become uniform.
Working: The limit of variation of speed and acceleration are defined as threshold values. The Micro Computer constantly compares the signals from the speed sensor mounted on each axle with the reference speed. If the speed/ acceleration of any axle are crossing the present threshold values, it gives signal to the respective Rapid Discharge Valve to release the BC pressure accordingly, thus maintaining the speed/acceleration within the threshold level.
Advantages of LHB coaches
- Better payload to tare ratio.
- Better safe guard for corrosion.
- Increased coach availability due to reduced maintenance.
- Higher carrying capacity of 78 passengers in chair car.
Air Brake Testing Procedure for LHB Coaches:
On arrival of the rake on pit line, completely drain the AR tank (125 litres & 75 litres) of all the coaches by opening the drain cock, to remove the water in air.
Initially, couple the BP hose of the test rig with the BP hose of the rake & then charge the BP pressure to 5.0 kg/cm2 . Keep the FP angle cock of both end power cars in close position. Check the FP gauge fitted in the power car, if the gauge does not show any pressure, the NRV of all the coaches are ok. If, FP gauge shows any pressure, the NRV of some coach in the rake is defective. In this condition, check the rake for NRV defective by taking the coaches in parts. NRV found defective in particular coach should be replaced.
Open all the four cocks of rake, couple BP & FP hose pipe of test rig with the BP & FP hose pipe of the rake. Charge the BP & FP to 5.0 kg/cm2& 6.0 kg/cm2 respectively. After building of 142 pressure in BP & FP, disconnect the test rig BP & FP hose pipe from the rake hose pipes & open both the angle cocks, due to which air pressure will be exhausted in atmosphere & brake will be applied. Wait for 20 to 25 minutes.
After 20 to 25 minutes, check the complete rake from one end. Note down the coach nos. found with released brake cylinder. Check whether, AR tank of the coach is charged or empty. If AR tanks found empty, write down Empty AR on the respective coach. If found charge, pull manual release of DV to check whether CR tank is charged / empty. If CR found empty, write down Empty CR on respective coach. With this, all the defects in the rake can be checked.
Again, connect BP & FP hose pipe of the rake & test rig & then charge BP to 5.0 kg/cm2 & FP to 6.0 kg/cm2 . Connect BP & FP gauges with dummy on free end of other end power car.
Check the BP & FP pressure gauges in front power car, BP pressure should show 5.0 kg/cm2 & FP pressure should show 6.0 kg/cm2 . If there is any difference in any pressure, check by fitting master gauge if still the pressure is not showing 5.0 kg/cm2 in BP & 6.0 kg/cm2 in FP, check for leakage & attend.
Close the BP & FP angle cock of test rig for 03 minutes. Monitor the leakage in both BP & FP. The leakage should not be more than 0.6 kg/cm2 in 03 minutes.
Attend the coaches in which AR empty & CR empty are found. Check the AR tank & pipe line from the back of the brake panel for leakage. Similarly, check CR tank & pipe line & dummy plug on the brake panel. If defect is still noticed after attending the leakage, then mark the coach sick for detailed investigation & single car testing in sick line.
Start the pressure & charge the BP to 5.0 kg/cm2 & FP to 6.0 kg/cm2 . Drop the BP pressure by 1.6 kg/cm2 , brake should apply in all coaches. Start the leakage checking with the help of soap solution from one end. During soap solution testing, check all the BP & FP hose pipe, all hose pipe connectors, Main pressure pipe line, Angle cocks, Brake cylinder pipe line, CDTS pipe line. Similarly, check & attend leakage in components on Brake panel like DV, FP & BP filter, NRV, all isolating cock, brake indicator, brake accelerator & brake cylinder with soap solution.
Isolate the isolating cock on Brake panel & check all brake calipers & brake pad of all cylinders. In isolated condition, all brake pads should be released simultaneously. Similarly, on opening of isolating cock all Brake cylinder should operate & brakes should apply.
Check the brake indicator when brakes are applied, indicator should display red colour. However, when the brakes are released from isolating cock the brake indicator should display green colour. If on brake release condition, brake indicator is not showing green or on brake applied condition brake indicator is not showing red, then the brake indicator is defective. Repair / replace the brake indicator.
The BP & FP pressure gauges in the others end power car should show pressure 3.4 kg/cm2 & 5.8 – 6.0 kg/cm2 respectively. If any difference in above pressure is noticed that means there is any cross connection in BP & FP connection. Attend the same & ensure BP pressure 3.4 kg/cm2 & FP pressure 5.8 – 6.0 kg/cm2 .
Charge the BP & FP pressure to 5.0 kg/cm2 & 6.0 kg/cm2 respectively. Check the brake indicator of complete rake, all coaches should be in released condition. If any coach is not released, it means that the CR of that particular coach may be 144 overcharged & there is an internal defect in DV. Mark the coach sick for detailed investigation.
Check PEASD of at least 03 coaches. During PEASD checking, brakes should apply in all coaches & the brake accelerator should operate. Coach numbers should be noted in maintenance diary.
Now close the pressure supply from the test rig. Operate the emergency guard van valve of front power car guard van. BP pressure should become 0.0 kg/cm2 in approx. 25 to 30 sec in front power car & approx. 40 to 50 sec in rear power car. Open the pressure supply & charge BP & FP to 5.0 kg/cm2 & 6.0 kg/cm2 respectively. Now again close the pressure supply from the test rig. Operate the emergency guard van valve of rear power car guard van. BP pressure should become 0.0 kg/cm2 in approx. 25 to 30 sec in rear power car & approx. 40 to 50 sec in front power car.
Check for any significant difference in time for droppage of BP pressure to 0.0 kg/cm2 between front & rear power cars. If any, there may be blockage in BP line of any coach. If found, attend the same. Continuity test of the rake is now completed.
In both the power cars, check the condition & mounting of hand brake cables fitted on both the brake cylinders. Rotate the hand wheel fitted in guard van clockwise to apply the brakes, after full rotation brake should apply in both the brake cylinders & hand brake indicator should show red. Rotate the hand wheel anti clockwise, now brakes of both the cylinders should get release & hand brake indicator should show green.
Charge the BP & FP to 5.0 kg/cm2 & 6.0 kg/cm 2 respectively. Close the BP & FP angle cock of test rig for 03 minute. Monitor the leakage in both BP & FP. The leakage should not be more than 0.6 kg/cm2 in 03 minutes.
Isolate the isolating cock of BP & FP of the test rig & angle cock of BP & FP of the cock. Uncouple both hose pipes & open both the angle cocks of coach. After draining of pressure from both the BP & FP hose, release the complete rake by pulling the manual release handle of the DV of each coach & ensure the brake indicator of all coaches should display green colour. Ensure that all BP, FP & BC gauges fitted in power car are calibrated & showing correct reading.
3.6 WSP Testing Initially with no pressure, the WSP processor in all the coaches should be OFF. If any processor is in ON condition, there is problem in any of pressure switch, wiring or K-05 relay. Attend the same.
Start the BP & FP pressure. The processor should automatically ON when BP pressure reaches 1.6 to 2.0 kg/cm2 in M/s KNORR WSP system & when FP pressure reaches in M/s FTIL WSP system.
Check & attend for loose/proper fitment of WSP components like speed sensor, junction box, dump valve, dump valve connector & pressure switch.
Drop the BP pressure by 1.6 kg/cm2 , brake should apply in all the coaches. Now check the WSP processor for correct reading ‘99’ on the electrical panel inside the coach. If the reading shows ‘99’, it means that the WSP system is OK. Operate the test button on the processor to check the proper working of dump valves. The dump valve should operate in a sequence & pressure should be exhausted from brake cylinder. If the dump valve is not operated in proper sequence attend the same. Similarly, check & attend the 146 WSP system of all the coach. All the WSP system should be in operating condition in the rake.
Single car test procedure
Please ensure that all the pipe fittings, brake equipment are properly fitted and in place before starting the testing.
Railway Employee
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