AIR SUSPENSION SYSTEM IN EMU

PRESENTED BY

E.M.U.CARSHED / HOWRAH EASTERN RAILWAY

INTRODUCTION

• PREVIOUSLY END GROUNDED CLOSED COIL

HELICAL SPRINGS WITH OIL DUMPER / SHOCK

ABSORBER ARE USED BOTH FOR PRIMARY

AND SECONDARY SUSPENSION.• BUT NOW AIR COLUMN IS USED IN PLACE OF

COIL SPRING IN SECONDARY SUSPENSION

DUE TO ITS CLASSIC CHARACTERISTICS OF

VARYING STIFFNESS.

EMU COACHES ARE PROVIDED WITH DOUBLE STAGE SUSPENSION SYSTEM –

• PRIMARY SUSPENSION• SECONDARY SUSPENSION

ADVANTAGES OF AIR SUSPENSION SYTEM

1. CONSTANT HEIGHT OF COACH IRRESPECTIVE OF LOAD.

2. NO CHANCE OF PLATFORM RUBBING.

3. VERY SMOOTH RIDING.

4. LESS MECHANICAL FAILURE.

5. LESS MAINTENANCE.

AIR SUSPENSION BOGIE FOR EMU

SHOCK ABSORBER

BOLSTERLEVELING VALVE

INSTALLATION LEVERAIR SPRING BELLOWDUPLEX CHECK VALVE

HISTORY

• In the year 2001a trial had been done by RDSO on 3-point and 4-point air suspension coaches. • After the trial RDSO declared that the 3-point suspension system is not suitable for EMU service.• Only 4-point suspension system remain is in system and one trailer coach with 3-point suspension is converted to 4-point suspension as per ICF drawing by CS/HWH & in one Motor with 3-point suspension is in service with conventional coil springs in secondary.

AIR SUSPENSION BOGIE FOR EMU

SHOCK ABSORBER

BOLSTERLEVELING VALVE

INSTALLATION LEVERAIR SPRING BELLOWDUPLEX CHECK VALVE

WORKING PRINCIPLEAir from MR flows to air spring bellow through levelingvalve when this valve is in charging position. As the pressure inside the bellow increases bellow heightincreases as well as bolster also lifts up and the linkof leveling Valve approaching to horizontalposition. When the Leveling valve enters within deadband zone no further air will flow to bellow. Now ifthe load on air spring increases, bolster goes downand leveling valve will be in charging conditionadmitting more air into the bellow. This causesbolster again lifts up to the preset level.

Now when the load on air spring decreases, the bolster goes up and leveling valve will be in discharging mode. Then air from bellow flows out to atmosphere through leveling valve. Thus bolster as well as leveling valve goes down up to the same preset level.

WORKING PRINCIPLE

LEVELING VALVELEVELING VALVE

SCHEMATIC DIAGRAM FOR 4-POINT AIR-SUSPENSION

DUPLEX CHECK VALVE

AS

DUPLEX CHECK VALVE

INSTALLATION LEVER

ISOLATING COCK FOR AIR-SUSPENSION

TWO WAY DIRT COLLECTOR

150

LT

RS

. R

ES

ER

VO

IR

AS

CHECK VALVE

INSTALLATION LEVER

MAIN RESERVOIR PIPE LINE

20 L

TR

S.

RE

SE

RV

OIR

20 L

TR

S.

RE

SE

RV

OIR

POPULATION

Division Bellow

(Contitech)

Bellow

(Firestone)

Leveling valve

(Knorr-bremse)

Leveling valve

(FTIL)

Duplex check valve

(Knorr-bremse

Duplex check valve

(FTIL)

HWH 173 39 116 96 58 48

SDAH 292 80 172 200 92 94

TOTAL 465 119 288 296 150 142

Division Vertical

Shock absorber

(300 kg.)

(ESCORTS)

Vertical

Shock absorber

(300 kg.)

(Gabrial)

Vertical

Shock absorber

(300 kg.)

(IAI)

Lateral

Shock absorber

(200 kg.) (ESCORTS)

Lateral

Shock absorber

(200 kg.) (Gabrial)

Lateral

Shock absorber

(200 kg.)

(IAI)

HWH 194 NIL 18 194 NIL 18

SDAH 260 86 26 260 86 26

TOTAL 454 86 44 454 86 44

PNEUMATIC

MECHANICAL

TOTAL FAILURE (IN HWH DIV.)

1. Hose 30 NOS

2. Lateral shock absorber 12 NOS.

3. Installation lever 16 NOS.

4. Duplex check valve 03 NOS.

5. Miscellaneous 02 NOS

6. Bellow NIL

7. Leveling valve NIL.

8. Vertical shock absorber NIL

MOTOR COACH NO. 60040

DATE OF COMMISSIONING – 31.03.2005.

DATE OF LAST POH – 01.03.07.

DATE OF FAILURE – 15.11.07.

VERTICAL SHOCK ABSORBER

TOP HOLDING BRACKET FOR VERTICAL SHOCK ABSORBER

FAILURE OF VERTICAL SHOCK ABSORBER (IN HWH DIV.)

FAILURE OF HOSE (IN HWH DIV.)

• Rubber braided flexible hose.

About 30 nos of flexible rubber braided hose out of 108 nos. had been failed within 09 months of commissioning. These were replaced by CS/HWH/E.Rly.

• Population of hose per coach - 08 Nos.

FAILURE OF RUBBER HOSE (IN HWH DIV.)

POPULATION

LIFE TOTAL FAILURE

FRPCPY

312

• 12 NOS. – 07 YRS.

• 54 NOS. - 03.33 YRS.

• 54 NOS. - 03 YRS.

• 54 NOS. – 01.17 YRS.

• 30 NOS. – 0.42 YRS.

• 54 NOS. - 0.25 YRS.

• 54 NOS. – 01 MONTHS.

30 NOS. 5.8

FAILURE OF LATERAL SHOCK ABSORBER (IN HWH DIV.)

THERE ARE A GOOD NUMBR OF FAILURE OF LATERAL SHOCK ABSORBER DUE TO BREAKAGE OF ITS FIXING BOLTS. THESE FAILURES WERE TAKEN PLACE WITHIN 05 MONTHS OF COMMISSIONING IN M/S JESSOP & CO. MAKE COACHESONLY.

AVAILABLE GUIDELINES FROM RDSO/LKO CMI 9802 (REV. 1) MAY 2001

& (REV. 2) FEBRUARY 2008.

• PROCEDURE FOR LEAKAGE TESTING AND PERMISSIBLE LEAKAGE.

• PROCDURE OF CHECKING BOGIE CLEARANCES AND CENTRE BUFFER COUPLER HEIGHT ADJUSTMENT.

• PROCEDURE FOR PROCEDURE FOR INSTALLATION LEVER ADJUSTMENT.

• GENERAL TECHNICAL DATA FOR SPRINGS.• MAINTENANCE SCHEDULE.• SUSPENSION DATA.

GUIDELINE REQUIRED

• MR PRESSURE SETTING.

• CLEANING OF FILTER FOR LEVELING VALVE.

• EXCESS RUNNING TIME OF MCP.

• PROBLEM WITH MAINTENANCE OF M/S FTIL MAKE LEVELING VALVE REGARDING LEAKAGE.

• NON INTERCHANGEABILITY OF BASE PLATE FOR AIR SPRING BELOW.