Carriage & Wagon Workshop

Eastern Railway
Liluah

EPPFS
SYSTEM LAB

Shibnath Banerjee Road, P.O. – Liluah, Dist. – Howrah

State – West Bengal, Pin – 711204.
 ABBRIVATION

& And
EPPFS Electro-Pneumatic Pressurized Flushing System
LHB Linke-Hofmann -Busch
POH Periodic Overhauling
BV Ball Valve
V Volt
DC Direct Current
WS Water Strainer
FV Flush Valve,
NRV Non return Valve
WLU Water Locking unit,
AFR Air Filter cum Regulator & Lubricator
SS Stainless steel
Al Aluminium
SMPS Switched Mode Power Supply
AFRL Air Filter cum Regulator & Lubricator
 INDEX
S Topic Page No.
No.
1 Developmental History 01
2 Classification of Flushing system in Indian 01
Railways
3 Advantages of Using A Test Bench for 01-02
EPPFS
4 Flow Chart for Work of EPPFS During POH 02
5 Schematic Diagram of Demonstration cum 03
Test Bench of EPPFS
6 Major Components Attended at EPPFS Lab 03
7 Maintanance of EPPFS During POH at 04-07
LLH/WS
A) Pressurizer Unit
B) Control Panel
8 Root Cause Analysis 08
9 Root Causes 08
10 Common Defects Faced 08-09
11 Summary of Issues 09
12 Recommendations 09-10
13 Trouble Shooting 10-11
14 Sources Developed for Supply of Component 11-12
for Existing EPPFS of Different Make
A) New Sealing Kit
B) New Piston
15 PFS/EPPFS Material List 13
Annexure-I 14
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C & W Workshop, Eastern Railway, Liluah EPPFS System Lab

1. Developmental History:
EPPFS system can be grouped into two parts i.e. mechanical & Electrical.
Mechanical parts consist of Pressurizer unit including with water locking unit &
NRV. Electrical parts come with a dedicated Control Panel. Usually, when a LHB
coach in turned for POH, Water, Pneumatic & electrical connection gets stripped
off. Hence complete testing of EPPFS system gets hampered.
To mitigate these issues of EPPFS testing a dedicated lab has been set up at
LLHWS. In this lab pressurizer unit which are stripped off (100% stripping done
during POH) from in turned coaches overhauled & tested for functionality. This
lab is also capable to testing the control panel of the system on condition basis.
2. Classification of Flushing system in Indian Railways:

3. Advantages of Using A Test Bench for EPPFS:

A. Quality Assurance: A test bench allows for rigorous testing of measure component like
pressurizer unit& control panel of the Electro-Pneumatic Pressurized Flushing
System before installation or deployment. This ensures that all parts meet quality
standards and operate as intended, reducing the risk of malfunctions or failures
during applications in coaches.
B. Performance Optimization: By simulating various operating conditions and
scenarios, a test bench enables us to optimize the performance of the flushing
system. They can fine-tune parameters such as flushing duration (6-8 sec.),
pressure levels (2-3 kg /cm2), and valve timing to achieve optimal efficiency and
effectiveness.
C. Fault Detection: Test benches facilitate the detection of any potential faults such
as air leakage and water leakage in the Electro-Pneumatic Pressurized Flushing
System. We can systematically test each component i.e. WLU & NRV to identify
and address any issues before they escalate into larger problems during flushing.

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D. Cost Savings: Identifying and rectifying design flaws or performance issues early
in the development process can lead to significant cost savings. Test benches
enable us to iterate and refine the design efficiently; minimizing the need for expensive rework
or recalls after the system has been deployed.
E. Time Efficiency: Testing the pressurizer unit of Electro-Pneumatic Pressurized Flushing System
on a dedicated test bench streamlines the development and validation process. We can conduct
comprehensive tests in a controlled environment without disrupting production schedules or
waiting for testing opportunities.(during scheduled outturn)
F. Damage percentage: By using a test bench damage percentage has been reduced mainly in
pressurizer unit including WLU& NRV.
G. Documentation and Compliance: Test bench testing generates valuable data and
documentation that can be used to demonstrate compliance with industry standards and
regulatory requirements.
4. Flow Chart for Work of EPPFS During POH :

EPPFS

Pressurizer Unit Control panel

Strip 5/2
Strip Controller/ Pneumatic
Strip Water cylinder Strip Water locking unit Strip NRV Timer &DC to DC solenoid valve
Converter/SMPS (electric operated)

Strip inner parts, clean with

citric acid & replace sealing kit Supply input 24V
To be clean & check Supply input 24V
/ piston if corroded DC/110V DC with
DC/110 V DC
pneumatic supply

Check output voltage of Check change

Refit inner parts of cylinder Replace if not working converter/timer as 24V / in air direction
110V DC, 6-8 seconds

If no output then repair / If no change in

Refit cylinder with all fittings (water locking air direction
replace it
unit, NRV & push fittings repair/replace the
coil or solenoid
valve

Check Pressurizer unit (water cylinder) using

test bench water pressure of cylinder should
Refit control panel & test all function
be 2-3 kg/cm2 properly

Check complete function of EPPFS system as per manual

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 C & W Workshop, Eastern Railway, Liluah EPPFS System Lab

5. Schematic Diagram of Demonstration cum Test Bench of EPPFS :

WATER IN
CONTROL PANEL
CYLI 1. DC TO DC CONVERTER
PIPE LINE (110 -24) V
NDE 2. CONTROLLER

BV(IC) R 3. AIR SOLENOID VALVE

AIR LINE AIR IN

PIPE LINE -- (
AFRL

IC

(PU TUBE FOR AIR CONNECTION)

FV ELECTRIC
SWITCH

ELECTRICSWITCH
SS PAN/COMMODE
NRV

TEE

NRV
WLU Cylinder to be connects &
NRV
CYLINDER tests here

Pressure Gauge

6. Major Components Attended at EPPFS Lab:-

6.A. Pressurizer Unit

 Cylinder
 Water Locking Unit (Angle Sheet valve)
 Non Return Valve
6.B. Control Panel
 DC to DC Converter
 Controller
 Solenoid Valve (5/2 type)
 Air Filter cum regulator
 Electric Switch (24V DC/ 110V DC)

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C & W Workshop, Eastern Railway, Liluah EPPFS System Lab

7. Maintanance of EPPFS During POH at LLH/WS

Visual inspection of all components of EPPFS, water pressurizer unit (water
cylinder including water locking unit (check valves), Non return valves and electrical
connections of SMPS, control panel controller including with AFRL, electric switch,
solenoid valve to check for wear & physical damage .

7.A Pressurizer Unit:

i) Strip water pressurizer unit (water cylinder)

from coaches & take it into EPPFS Lab.
ii) Strip pressurized unit (water cylinder) inner &
outer parts using bench vice & vertical hydraulic
press machine.
iii) Check SS barrel & Al barrel if any dents,
corrosion, deformation & inner diameter
through vernier caliper as applicable etc. persist
then repair/replace the same.

SS Barrel Al Barrel

iv) Airless filter (silencer) fitted in middle cover of cylinder to be cleaned with soft
brushes and replaced with new. This is very crucial for proper operation of
pressurize unit (cylinder).

Port for Air release

filter / silencer

New Air release filter / silencer

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C & W Workshop, Eastern Railway, Liluah EPPFS System Lab

v) Remove scaling of cylinder SS barrel, front cover, end

cover, middle cover, SS tie rods & SS angle sheet of
WLU in crate using 4% citric acid solution for
minimum 1 hr.

Crate
vi) Water locking unit & NRV should be
checked, remove scaling, repair & replace if
necessary.

NRV Water Locking Unit

vii) After cleaning of cylinder, replace sealing kit (must change item) of cylinder.

 Damaged Sealing Kit

SN Make Picture Remarks

O-ring and piston seal and

1 SPAC guide ring was damaged and
loose.

O-ring and piston seal and

guide ring was damaged,
loose & broken.

IMI
2 Wiper seal of
NORGREN
middle cover of
cylinder was
badly damaged.

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C & W Workshop, Eastern Railway, Liluah EPPFS System Lab

viii) Replace piston of cylinder if corroded/damaged to avoid any leakage.

 Damaged Piston
SN Make Picture Remarks

Orifice of the piston of cylinder was

1 NBC
defective.

Orifice of the piston of cylinder was

IMI
2 badly corroded due to corrosive
NORGREN
water.

ix) Refit cylinder with their fittings (including water locking unit, NRV & push fittings).

x) Connect pressurized unit (cylinder) in test bench with

appropriate water hose connections & pneumatic
connections (3 to 5 kg/cm2) & ensure power supply in
control panel.
xi) Press to flush.
xii) Check water pressure, it should be 2-3 kg/cm2 if ok then
send it to fitment in coach, if not then repeat the
process & rectify the same.

7.A.i Testing Parameters:

Pressurization time 6-8 Seconds

Flushing Pressure 2-3 Kg/cm²
Water Consumption 1.5 Liters
Air Consumption 3 Liters approx./cycle
Power Consumption ≤ 10Watt/Lavatory

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7.A.ii Testing of Pressurizing Unit

S.N. Description Method

1 Water Pressure By Dial Gauge

2 Water Volume Measurement by Measuring Flask after 10 Cycle & taking

average

7.B .Control Panel:

i) After visual inspection of control panel, all

connections of DC to DC converter, controller
and solenoid valve to be checked.
ii) Control panel will be checked after giving
electric supply available in coach. If there is
any deficiency in controller, converter and
solenoid valve, the control panel is stripped and
it is taken to the test bench room for further
examination in EPPFS lab.
iii) Connect & check timer/controller with 24V or Control Panel Test Bench
110V DC input supply & output supply as
applicable, connect with electric board and
followed by testing at test bench. If there is no
output then replace timer/controller.
Note: Controller/timer output should be 24V
DC or 110V DC for the duration of 6 to 8
seconds.
iv) Connect & check solenoid valve with electric
supply 24V or 110V DC input & pneumatic
supply (3 to 5kg/cm2). If there is no change in
air directions (through spool valve) then
repair/replace the coil. Recheck the Solenoid
Valve again. If still it is not working, then
replace the Solenoid valve.
v) Check DC to DC converter or SMPS input
supply 110V dc & output supply 24V DC. If
output not available then repair/replace it.
vi) After following the above steps, then we check
the complete control panel. If it is OK then it is
sent for fitment in coach.

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8. Root Cause Analysis

 As per design pressurizer unit (Cylinder) in EPPFS has different chamber /barrel for
air and water.
 As per design water & air should not come in contact with each other.
 But due to corrosion and faulty seals inside cylinder, water ingress towards air
chamber.
 Successively, it ingresses to all air ports including solenoid valve & also to air filter.
9. Root Causes:
 Excess corrosive water.
 Sludge/mud mixed water.
 Quick damage of sealing kit inside cylinder.
 Oxidation of aluminium barrel and piston, resulting faster wear out.

10. Common Defects Faced

Solenoid Valve • Air leakage from spool/port
due to rust.
• Coil of solenoid valve found
defective.
• Air exhaust filter found Solenoid
rusted & dirty. Valve

Electric switch • Connector of switch &

connection socket found
defective/damaged.
• Push to flush found inactive.

Switch Connector Flush Switch

Flushing Switch • Knob of manual flushing

Assembly switch found defective.
(Pneumatic only) • Spool found sticky and
rusted.
• Air leakage from spool due to
rust.

Non Return Valve • Found Leaky & Rusted.

• Spring found damaged &
sticky due to corrosion &
sediments.

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 C & W Workshop, Eastern Railway, Liluah EPPFS System Lab
VNB (Pilot Valve) • Found Leaky, rusted &
inoperative (full of sediment).
• Spring found damaged.
• Inactive spring action in
water seal pilot valve.

Pressurizer Unit • Seizing /jamming of

(Cylinder aluminium piston.
• Damaged /wear out
Aluminium piston & barrel
due to corrosion.
• Damaged Sealing Kit.
• Rusted Tie Rods.

11. Summary of Issues

• Pressurizer unit (Cylinder) found leaky, rusted & sticky.
• Inner parts of cylinder i.e. sealing kit, cylinder etc. found sticky, damaged and
corroded.
• Water locking unit & NRV found damaged due to corrosion and sediment.
• Control panel found rusted & damaged due to water dripping, dust ingression.
• Non availability of different components from different makes.
• Flushing switch assembly & electric switch found rusted and defective.

12. Recommendations

• There are several vendors for EPPFS with several design & dimension.
Design of cylinder including sealing kit & piston need to be standardized for
interchange ability & flexible overhauling purpose.
• As per MMDTS 19027 Rev03, water side cylinder piston is made up of AISI 304
& air side by Anodized Aluminium as per IS 1285: 2002 63400 T6. It is
recommended, Piston cylinder for air side also need to change into AISI 304
(as water side) to avoid “Bi metallic corrosion”.
• As per MMDTS 19027 Rev03, Solenoid valve (5/2 type) and Air Filter should be fitted
inside the control panel to reduce chances of dust ingression & rusting from
moisture. Dehumidifier / Activated alumina may be used to prevent
moisture.
• Electric switch socket as per MMDTS 19027 Rev03 need to be covered properly to
reduce damage and electric short circuit. In this context dimension & design may
need standardization.
• Treated water with sediments filter is required in EPPFS system to reduce
corrosion.
• Test bench introduction in all depots may be compulsory.
• Standardization of ph value of water in all filling stations.

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• Warranty period: In MMDTS 19027 Rev. 01, it was 72 months (6 years), but in
Rev.03 it has changed to 24 months only. It is recommended that the warranty
period may be extended up to next POH.
• In EPPFS system, quality of sealing kit inside cylinder & springs in various
valves play a pivotal role. Whereas in concerned spec. there has no specified details
for standard quality. Proper quality standardization (including test parameter)
may help to improve reduction in failure cases

13. Trouble shooting:

Troubleshooting an electro-pneumatic pressurized flushing system typically involves
addressing common problems that can arise during its operation. Here are some typical
issues you might encounter and steps to troubleshoot them:

GENERAL PROBLEMS REMEDIAL ACTIONS

Flushing is not working  Check Power Supply:110V DC
(No Flushing Action):  Ensure that the system is receiving power. Check
circuit breakers, fuses, and power connections DC
to DC converter or (SMPS) (110V- 24 V DC),
PLC/Controller & solenoid valves (within control
panel).
 Check & ensure electrical connection & polarity.
 Inspect Solenoid Valves(5/2 type):
 Verify if the solenoid valves are functioning
properly. Use a multimeter to check if they are
receiving the correct voltage in coils (as applicable)
and if they are opening and closing (pneumatic
port) as commanded.
 Examine Control Signals:
 Check the control signals from the PLC or
controller to the solenoid valves. Ensure there are
no loose connections or broken wires.
 Check push button LED and timer is glowing.
 Review Pressure and Air Supply:
 Ensure that the air compressor or pneumatic
system supplying air to the system is operational
and providing sufficient pressure.
Partial Flushing or  Adjust Air Pressure Settings (3kg/cm2):
Incomplete Cycle or  Check ball valve in air is fully open
Delayed Flushing:  Verify and adjust the pressure regulator settings
to ensure they are appropriate (3kg/cm2) for the
flushing process. Incorrect pressure settings can lead to
inadequate flushing action.
 Check for Air Leaks:
 Inspect air lines, ball valve, fittings, and pneumatic
components for leaks. Even small leaks can affect
the performance of the system, causing incomplete
flushing cycles.

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 Clean or Replace Filters/silencers:
 Clogged air filters & silencers can restrict
airflow (such as solenoid valve/WLU/middle
cover of cylinder) to the system. Clean or replace
filters as necessary to maintain optimal air
pressure and flow.
Water Flow Issues:  Inspect Water Supply Lines:
 Check for blockages or restrictions in the water
supply lines, ball valve, water strainer and pan
nozzles as well. Clean or clear any obstructions
that could hinder water flow during the flushing
process.
Issue in Pressurizer unit  Inspect Pressurizer unit (Mechanical
(Mechanical Components):
Components):  Ensure all mechanical components, such as WLU,
NRV & cylinders and moving parts, are lubricated
and functioning correctly. Tighten any loose
connections or replace worn-out parts
 Ensure WLU are cleaned & working properly.
 Ensure NRV are cleaned & working properly.

14. Sources Developed for Supply of Component for Existing

EPPFS of Different Make

14.A. New Sealing Kit

SN Make Name & Contact of Qty. / Picture
Supplier set

AIR INDIA ANIRBANENTERPRISE

1 10 nos.
PNEUMATICS 9831441609

ANIRBAN ENTERPRISE
9830441609
JANATICS
2 SHIVA ENGINEERING 13 nos.
INDIA LTD
WORKS
9433311593

ALFA SUPPLY CO-

KOLKATA
7980517756
3 SPAC 10 nos.
SHIVA ENGINEERING
WORKS HOWRAH
9433311593

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TECHNO SOLUTION-
EAST BURDWAN
9051088482
IMI ANIRBAN ENTERPRISE
4 13 nos.
NORGREN 983044160
SHIVA
ENGINEERING WORKS
9433311593

ANIRBAN ENTERPRISE
5 AIR FLOW 13 nos.
9831441609

14.B. New Piston

SN Make Name & Contact of Qty. / Picture
Supplier set
ANIRBAN
ENTERPRISE
9830441609
IMI
1 SHIVA 01 no.
NORGREN
ENGINEERING
WORKS
9433311593

ANIRBAN
AIR INDIA
2 ENTERPRISE 01 no.
PNEUMATICS
9831441609

ANIRBAN
ENTERPRISE
9830441609
JANATICS 02
3 SHIVA
INDIA LTD nos.
ENGINEERING
WORKS
9433311593

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15. PFS/EPPFS Material List :-

Items Required during POH Must change item

(suggested by LLHWS)
Pressurizer Unit (Water Cylinder Unit) Sealing Kit of pressurizer unit (Cylinder).
Sealing kit & piston of water cylinder Air release filter/silencer (1/4” & 1/8”) of
middle covers plate.
Water locking Unit (¾” port size) & Air release filter/silencer (1/4” & 1/8”)of
Springs 5/2 solenoid valve.
Manual flushing switch assembly Push Air release filter/silencer (1/4” & 1/8”) of
type 5/2 pneumatic valve (Purely water locking unit.
pneumatic for PFS)
Electric push button & Cover plate Connecting tubes (8 mm/10 mm)
Control panel with SMPS/DC to DC Air Filter cum regulator & lubricator
converter, PLC/Timer(controller) & (AFRL) with calibrated pressure gauge
solenoid valve
Pneumatic Isolating Valve 1/4" (Both end Nyloc Nut during fitment of Pressurizer
female thread) Unit (cylinder).
Air filter cum regulator & Lubricator Push Fittings (Elbow, straight connector
(AFRL) & Tee)
Water Isolating valve 3/4" (Both end Hose Pipe Connection
female thread)
NRV 3/4" Hose Clamps

NRV 1/2" Piston of Water Side Cylinder

Water Hose 20mm Bore

Hose Clamp size 30mm

Air silencer (1/4” & 1/8”)

Pneumatic tubes (10mm,8mm,6mm) &

push fittings elbow (10 mm,8mm,6mm),
tee connector (10 mm,8mm,6mm), straight
connector(10 mm,8mm,6mm)

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ANNEXURE-I
Check sheet of Pressurized Flushing System/Electro Pneumatic Pressurized Flushing System
during SS2 & SS3
Coach no. Code: Div.: Date:
SN Activities Lav. no.1 Lav. no.2 Lav. no. 3 Lav. no. 4
1 Activate the push button and check the correct
functionality of flushing
2 Check & ensure the connectivity of input power
supply
3 Check & ensure the panel box is closed & firmly
mounted
4 Check and ensure Wires are intact & tied with
cable tie
5 Check & ensure the Push button Cover is firmly
tight
6 Check & ensure the illumination light of Push
Button is working
7 Check & ensure the AFRL ( Air filter cum
regulator & lubricator) Input and output Air
Connections are correct and in order. AFRL,
lubricant to be topped up as required.
8 Check & ensure 5/2 Valve Air Connections are
correct and in order (Port no.2 for suction stroke
& Port no.4 for ejection stroke). Replace air
silencer.
9 Check & ensure Pressurizer Unit (Cylinder) is
firmly mounted after overhauling & testing at
test bench.
10 Check the rusting of major parts. If rusted
severely, replace the part
11 Check & ensure the water inlet and outlet
Connections are correct & in order
12 Check & ensure the Y-water Strainer of Coach
is not chocked
13 Check & ensure the Hose pipes are not worn out
or squeezed (pinched) at bends. If found worn
out or squeezed (pinched) at bends, replace the
hose (Pipe Section)
14 Check & ensure the Silencer of Cylinder middle
cover & solenoid valves are not chocked(must
change)(as mentioned in Sl. No. 8)
15 Check the condition of NRVs & if found chocked
clean it or replace it, if severely corroded
16 Check & ensure the functionality of Water
Locking Unit. If found not working, Overhaul
the component & replace the parts if necessary
17 Check & ensure the functionality of pressurizer
unit. If found not working, Cylinder needs to be
opened and check the scaling level for operation
of Piston. Overhaul the component & replace
the parts. While reinstallation, same Nyloc nuts
should not be used. New Nyloc nuts to be used
18 Check & ensure water discharge from the
pan/commode bowls is satisfactory. If not, then
perforated holes of spray ring in the
pan/commode bowl assembly to be cleaned with
metal brush & pressurized water jet
19 AFRL needs to be replaced.
20 Pneumatic tubes to be replaced
21 Replace water locking unit, if found necessary
22 Ensure availability of passenger notification
near the push button, if not available
23 Check & Ensure the functionality of Manual
Push Button Flush Valve.(Replace if required)

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