1. 1
ACKNOWLEDGEMENT
Research Design and Standard organization (RDSO), ManakNagar Lucknow is
one of the best R&D centres in India which is governed by Indian Railway. This
report is based on the Summer Training carried out at RDSO under the guidance
of highly dedicated Staff working under this esteemed organization. I take this
opportunity to thank Each and Every person who helped me and supported me
directly or indirectly in completing this training.
I would like to express our sincere gratitude to Mr. D. K. Srivastav (Testing
Directorate Head of RDSO) for providing administrative permission for my
summer training through which knowledge is explored beyond the class room
boundaries. I duly express my gratitude to Mr. S.K. Mishra (In-charge Training)
for his support and guidance throughout this training session.
I am very thankful to Mr. R.S. Kashyap for giving his reference for the
enrolment in Summer Training program in RDSO.
I am thankful to all the lab in-charge and superintendents and with whose
support and guidance the creation of report came to existence. Last, but not the
least my sincere gratitude to all persons who remained unexpressed in words.
Shivanshu Dixit
B-Tech(ME)
2. 2
ABSTRACT
This report is about the Non destructive testing of the various essential
components of the Railway at Testing Lab like Brake and Dynamometer Lab,
Measuring Wheel Lab, Air Brake lab and Fatigue Testing lab under Testing
Directorate of RDSO during the One month Summer Training.
This report include the essential machinery, workforce, vital parameters etc, for
Simulation and testing of the undertaken design for validation of all newly
designed/modified rolling stock developed, whether in house or imported. It
also includes the actual field and static trails for the components like Brake
Blocks, Engine and Bogie wheels, safety equipments- Air brakes, and fatigue
testing of the bogie frame and the components which undergo fatigue stresses
under the constrained environment of Labs and generating results for the tests
and Setting standards for the INDIAN RAILWAY.
3. 3
Table of contents
1. Introduction…………………………………………....................................4
2. Testing Directorate……………………………..............................................6
3. Brake & Dynamometer Lab………………………………………………..7
3.1 Test Procedure and Allied Particulars………………………………….8
3.1.1 Physical Check
3.1.2. Bedding
3.1.3. Dry Test
3.1.4. Wet Test
3.1.5. Drag Test
3.1.6. Calculation of specific wear rate
3.1.7. Technical data and other observation
4. Measuring Wheel lab……………………………………………………..13
4.1. Prepartion of Measuring wheel & Instrumentation.. .… .……………14
5. Air Brake Lab……………………………………………………………..16
5.1. Types of Air Brake system …………………………………………..18
5.2. Working Principle……………………………………………………19
5.3 AB test rig system…………………………………………………….20
6. Fatigue Testing Lab
6.1. 100 ton measurement system………………………………………...23
6.2. 500 ton measurement system………………………………………...25
6.3 Stress Measurement…………………………………………………..29
7. Conclusion………………………………………………………………..31
8. References……………………………………………………………….32
4. 4
1. Introduction
INDIAN RAILWAYS, the premier transport organization of the country is the
largest rail network in Asia and the world’s second largest under one
management. Indian Railways owned and operated by the Government of India
through the Ministry of Railways. With the vast development in IR with the due
course of time such a big organization cannot run efficiently without adequate
R&D and design support. This is provided by RDSO at Lucknow.
Railways were introduced in India in 1853 and as their development progressed
through to the twentieth century, several companies managed and state owned
systems grew up. To enforce standardisation and co-ordination amongst various
railway systems, The Indian Railway Conference Association (IRCA) was
set up in 1903, followed by The Central Standards Office (CSO) in 1930, for
preparation of designs, standards and specifications. However, till
independence, most of the designs and manufacture of railway equipments was
entrusted to foreign consultants. With Independence and the resultant
phenomenal increase in country’s industrial and economic activity, which
increased the demand of rail transportation - a new organisation called Railway
Testing and Research Centre (RTRC) was setup in 1952 at Lucknow, for
testing and conducting applied research for development of railway rolling
stock, permanent way etc.
Central Standards Office (CSO) and the Railway Testing and Research Centre
(RTRC) were integrated into a single unit named Research Designs and
Standards Organisation (RDSO) in 1957, under Ministry of Railways at
Lucknow. The status of RDSO has been changed from an ‘Attached Office’ to
‘Zonal Railway’ since 2003. [1][2]
Organisation
RDSO is headed by a Director General. The Director General is assisted by
Additional Director General, Sr. Executive Directors and Executive Directors,
heading different directorates. RDSO has various directorates for smooth
functioning:
Bridges and Structures , Carriage , Defense Research , Electrical Loco , EMU &
Power supply , Engine Development , Finance & Accounts ,Geo-technical
Engineering ,Quality Assurance, Metallurgical & Chemical, Motive Power,
Psycho-technical , Research ,Signal , Telecommunication, Track, Testing, Track
Machines & monitoring, Traction Installation, Traffic, Wagon.
All the directorates of RDSO except Defense Research are located at Lucknow.
Cells for Railway Production Units and industries, which look after liaison,
inspection and development work, are located at Bangalore, Bharatpur, Bhopal,
5. 5
Mumbai, Burnpur, Kolkata, Chittaranjan, Kapurthala, Jhansi, Chennai,
Sahibabad, Bhilai and New Delhi.
Quality Policy
To develop safe, modern and cost effective Railway technology complying with
Statutory and Regulatory requirements, through excellence in Research,
Designs and Standards and Continual improvements in Quality Management
System to cater to growing demand of passenger and freight traffic on the
railways.[3]
Functions
RDSO is the sole R&D organization of Indian Railways and functions as the
Technical advisor to Railway Board, Zonal Railways and Production Units and
performs the following important functions:
Development of new and improved designs.
Development, adoption, absorption of new technology for use on Indian
Railways.
Development of standards for materials and products specially needed by
Indian Railways.
Technical investigation, statutory clearances, testing and providing
consultancy services.
Inspection of critical and safety items of rolling stock, locomotives,
signalling & telecommunication equipment and track components.
RDSO’s multifarious activities have also attracted attention of railway and non-
railway organizations in India and abroad.
Infrastructure
RDSO has a number of laboratories which are well equipped with research and
testing facilities for development, testing and design evaluation of various
railway related equipments and materials. Some of these are:
Air Brake Laboratory is equipped with facilities for simulating operation
of air brakes on freight trains up to 132 wagons and 3 locomotives as also
for simulation of passenger trains up to 30 coaches.
Brake Dynamometer Laboratory has facilities to develop and test brake
friction materials for locomotives, coaches and wagons. A unique facility
in India, this laboratory has also been used by R&D organisations of
Ministry of Defence like DMRL, DRDL and HAL for indigenisation of
brake pads for defence aircraft.
6. 6
Diesel Engine Development Laboratory has four test beds capable of
testing diesel engines from 100 to 6000 HP with fully computerized
systems for recording of over 128 test parameters at a time. This facility
has already enabled RDSO to develop technologies for improving fuel
efficiency, reliability and availability of diesel engines as well as to
extract higher output from existing diesel engines. Fatigue Testing
Laboratory for testing prototype locomotive and rolling stock bogies,
springs and other railway equipments subjected to stress and fatigue so as
to ascertain their expected life in service.
There are many more facilities in RDSO.
2. Testing Directorate
Testing Directorate of RDSO is one of the important directorates having field
units and testing labs. This Directorate undertakes design validation of all newly
designed/modified rolling stock developed, whether in house or imported.
Besides undertaking actual field and static trials, this Directorate has three
laboratories for conducting simulated trials on rolling stock sub-assemblies and
its various components.
In the year 1989 the present Testing directorate was created for carrying out all
dynamic and static mechanical testing activities of all type Railway Rolling
stocks. This directorate is looked after by Executive Director Research Testing.
The various tests and trials done by Testing Directorate can be broadly
classified into Field Trials and Laboratory Tests. Field Trials are those trials
which are conducted on newly designed prototypes and modified rolling stock,
for assessing ride quality and ride comfort apart from Route proving runs, Brake
trials and Coupler force trials to assess their behaviour in actual operating
conditions. Testing Directorate has also been entrusted with carrying out
periodic track monitoring runs on Rajdhani and Shatabdi routes.
Laboratory Tests are conducted on newly designed sub-assemblies and Rolling
Stocks components as well as quality audit check for assessing the suitability by
simulating service condition /field condition in three well equipped and
modernized laboratories.
Well-qualified, fully trained and vastly experienced dedicated team of 11
officers and 52 mechanical and instrumentation supervisors of the Directorate
are geared to meet the challenges posed in the field of testing of railway
vehicles and their components. [4][5]
7. 7
3. Brake & Dynamometer Lab
Following activities are done in Brake Dynamometer Lab
Mean and instantaneous coefficient of friction of brake blocks
Specific wear rate of brake block/pads
Maximum temperature attained by wheel and brake block/pads.
Variation of Coefficient of friction with change in environmental
conditions.
Emission of smoke and odour during dynamo testing in lab
A Brake Dynamometer Laboratory of RDSO has a dynamometer procured from
M/s MAN, Germany which was commissioned in 1974 and a new dynamometer
M/s Schenck Pegasus which was commissioned in 2005 for study of brake
material characteristics, development of new brake materials, study of braking
effect on wheels and quality control of brake block & disc brake pads. Salient
features of dynamometer equipment are as follows:
The new Brake Dynamometer housed in a hall measuring 28*10m. The actual
dynamometer measures 8.5*3.4*2.8m. The dynamometer machine is placed on
solid concrete floor. On this floor, the whole dynamometer rests on twenty nos.
( ten nos. on each side of dynamometer) of circular air cushions which act as
pneumatic vibration damper during the operation of machine.
The dynamometer is having two test stations thus allowing testing of one pair of
brake blocks at one work station and cooling of 2nd
work station at a time. The
dynamometer is also provided with the facility of testing of Disc brakes. The
dynamometer has facilities for simulation of maximum road speed of 300 km/h
with a one meter diameter wheel. An axle load up to 30ton & maximum brake
force of 6000kN per brake block can also be simulated. In addition to dry rail
condition, spraying water continuously on the wheel surface can also simulate
wet rail conditions.
For simulation of air impinging on the wheel, while the train is running,
ventilation system with fresh air volume range of 5200-15000m3
/h for cooling
wheel and brake block and maximum 16500 m3
/h of exhaust air for extracting
smoke, fumes and dust of the brake blocks out of the test stand exhaust is also
provided. The volume of fresh air can be selected as per requirement.
The control room is equipped with a Measuring cabinet consisting of Process
computer (VME) and has a control desk, which accommodates, control and
indicator switches and a data acquisition system .A dial meter displays the brake
cylinder pressure Rotation speed of wheel and braking time is digitally
8. 8
displayed. A PC has been provided for operator for loading the test programs
and as a user interface for dynamometer control and monitoring during the test.
The data of various brake characteristics e.g. speed, braking time, run out
revolution, brake torque, brake horse power, brake energy are recorded by the
data acquisition system (VEM) (DAS). The temperature of the Brake Block is
also recorded in the DAS with the help of thermocouples and Pyrometer, and
the temperature of the wheel is digitally displayed separately. The value of
mean coefficient of friction for individual brake applications is also recorded in
DAS. A graph of instantaneous μ versus speed is also drawn for each brake
application.
a. b.
Figure .1 a. Brake block Label for Testing*; b. Disk brake for Testing*
a. b.
Figure .2 a. MAN’s Dynamometer*; b. Schenck Pegasus’s Dynamometer*
3.1 Test Procedure and Allied Particulars
3.1.1. Physical Check:
After the receipt of the brake block samples in the laboratory, these are
registered and identification numbers are stamped on each brake block. These
9. 9
brake blocks are physically checked to ensure that they match the wheel profile
of the rolling stock for which testing is to be done.
3.1.2. Bedding:
The brake blocks are then fitted on the dynamometer for bedding to achieve
about 80% of the block contact area .This exercise is necessary to have a
uniform distribution of brake block force over the full brake block area during
the tests. Bedding of the brake block is done at a speed of 60km/hr and with a
brake block force of 2000kg .During bedding a wheel temperature up to 80-
1000
c is maintained.
After the contact area of the brake block is needed to about 80%, tests are
started as per test scheme.
3.1.3. Dry Tests:
Brake block are tested under dry condition at speeds of 40, 60,
80,100,110,120, 140 & 160 km/h with a brake block force of 3400kg and
at speed of 40, 60, 80 & 100 km/h with a brake block force of 4940kg.
Three applications are made at each speed and the initial wheel tread
temperature, as far as possible, is maintained b/w 70 and 1000
c. During
test, the volume of fresh air provided by the blower of ventilation system
is kept as 5200 m3
/h.
Various parameters e.g. braking speed, braking time, run out revolution,
brake energy, brake pressure, brake torque, temperature and
instantaneous and mean coefficient of friction are recorded on the data
acquisition system.
Ni-Fe/Ni type-K thermocouples are embedded on the brake blocks to
monitor the brake block temperature.
Wheel temperature is measured with Pyrometer, however, measured with
a highly sensitive contact less sensor INFRA radiation sensor mounted at
the wheel rim very close to the rubbing surface. This temperature is
digitally displayed.
At the end of the each test series, the brake blocks are inspected in respect
of grooving, metallic inclusion, burning, non-uniform wear, over heating
etc. and surface condition of wheel tyre in respect of polishing, pitting,
flaking, cracking and other defects.
Brake blocks are weighed for wear as per test schemes.
10. 10
3.1.4. Wet Tests:
As laid down in the specification, continuous flow of water at the rate of
14 l/h is allowed to fall on the top of the wheel through small nozzles of
1-mm dia during wet tests. It simulates the rainy season conditions.
During wet tests, blower is not used. This is to avoid flying away of water
falling on the top of the wheel.
Acceleration, running and braking at desired force are done in the same
manner as the dry tests.
During the wet tests, also inspection of both wheel and brake blocks is
done for any abnormally as of dry test.
3.1.5. Drag Tests:
After dry and wet tests on the brake blocks are over, the samples are
subjected to most severe type of braking, simulating controlling of train
on ghat section by applications of continuous brake.
The brakes are kept applied on the wheel for 20 minutes without
switching off the motor at a constant speed of 60 km/h. During drag tests,
torque equivalent to about 45 BHP is maintained. For maintaining of
constant torque, the brake force on the brake block is recorded at every 60
sec. At the end of 20 minutes maximum temperature attained by the
wheel and brake blocks are recorded. In case of brake blocks catching fire
or any abnormality observed in course of testing, further drag testing is
stopped.
Immediately after drag test brake block force is increased to 2400 Kg and
brakes are applied and various brake parameters are recorded.
A wheel having a dia of 1092mm was used for these tests. Tests were
carried out on Flywheel Mass test stand as per test scheme. Flywheel
masses having a moment of inertia of 3130 kgm2
including that of
revolving wheel and stub axle were engaged to simulate an axle load of
21.0 ton.
During drag tests phenomena like, emission of smoke and spark,
formation of red band and flaming etc. are recorded. At the end of the
test, inspection of the wheel and brake block is done to see any
abnormality on the wheel and brake blocks.
Since the test program starts acquisition of data for mean coefficient of
friction after development of 95% brake power in the brake cylinder.
Calculations are done as suggested in RDSO specifications.
11. 11
Figure .3 Graph Coefficient of friction vs. speed
3.1.6. Calculation of specific wear rate
From the table given below the specific wear rate value under dry & wet
condition is 2.06cc/kwh for brake block sample against the RDSO specified
limit of 4cc/kwh.
Specific wear rate= W*1000000 cc/kwh
D*E*2.72
Where, W= Total wear of the Brake Block in gm
D= Density of the brake shoe material gm/cc
E= Total energy dissipated during a particular series of test in kgfm
Sample
no.
Condition E(kgfm) W(gm) Density D
gm/cc
Specific wear
rate- cc/kwh
1 Dry 6619388 94.5 2.64 2.06
Wet (with
3400kg brake
force only)
Table .1. Specific wear rate of brake block under different condition.
3.1.7. Technical data and other observation
Other observation:
No metallic inclusion was observed during the bedding as well as during
testing of the sample.
No grooving, burning and overheating was observed from the brake block
during the tests.
The wheel tyre was having no pitting marks, no flaking, no cracking
during test.
12. 12
The normal light smell and smoke, as is prevalent in the entire
composition brake block, was experienced during the test particularly at
140 & 160 km/h speed.
Figure .4 Technical Data
Figure .5 Testing Condition on Schenck Dynamometer*
13. 13
4. Measuring Wheel lab
In measuring wheel lab Railway wheel (latest are LBH wheel) (Locomotive-
1092mm, Wagon-1000mm, coches-915mm) is prepared for simulation for
vertical and lateral forces. These are done on the Calibration Test Rig in which
Load application is done for Static and Dynamic condition for testing the
measuring Wheel. The test bench is hydraulic Pressurised for lateral and
horizontal force for simulating the actual working condition of the wheel.
Figure .6 Hydraulic testing rig for measuring wheel
Transducers are used for measuring the forces. Different types of transducers
which are used for measuring different type of force, some of them are:
Lateral transducers
Vertical transducers
Position transducers
While measuring prepare wheel by attaching transducers and making wheat
stone bridge arrangement depending upon the calculation that how many bridges
for lateral, vertical or for position.
Now, when load is applied the deflection measured by bridges in the form of
millivolts. The wheel is prepared by attaching wheat stone bridge all around the
wheel and its testing is done.
Results are generated via data acquisition system and interpolated for the mean
value.
Measuring wheel lab consists of following equipments:
14. 14
Power Pack which consists of stepper motor
A solenoid valve to vary hydraulic pressure
Testing rig
Load cells
Jib crane
DAS and other electronic sensors
4.1. Preparation of Measuring wheel & Instrumentation
The instrumentation is done as per test scheme. Normally,
instrumentation used for recording data is transducers as input device,
signal conditioners as processing device and chart recorders and/or
computerised data acquisition system as output device. Power supply unit
is used to provide power supply to signal conditioners and recorders and
excitation to passive transducers.
Transducers are used to measure acceleration, deflection and force.
Signal picked up from transducer is fed into signal conditioner for
processing. The processed output from signal conditioner can be recorded
on chart recorder and/or acquired on computer (PC or laptop) through
data acquisition cards.
Transducers normally used are passive types either resistive or inductive.
Transducer used for measurement of acceleration in x, y and z directions
is also called accelerometer and can be either, ‘strain gauge type’ or
‘piezo electric’. Transducer used for measurement of deflection of spring,
bolster, bogie movement etc can be either LVDT, i.e., linear voltage
differential transformer or string-pot. Transducer used for measurement
of force or load at axle box level is normally a load-cell. Measuring wheel
measures lateral and vertical forces at rail wheel level. Transducers are
excited either by 5V rms 2.5 kHz AC or DC voltage to provide output
signal.
Load cell assembly is used for recording lateral forces at axle box level.
Load cell of strut type is manufactured in-house suiting to the axle box
arrangement with range of measurement from 0 to 10t compressive load
only. Load cell is of full bridge resistance type and calibrated with
excitation voltage from 5 to 10V AC and under pre-calibrated hydraulic
jack. Its output is about 90 mV/V/tonnes. A load cell calibration chart is
prepared with load in tonnes on x-axis and mV output on y-axis. The
excitation voltage used during calibration is mentioned in the chart. Care
should be taken to use the same excitation voltage during trial.
15. 15
Measuring wheel is used for measuring vertical and lateral forces at rail
wheel level. FEM analysis of wheel conforming to s-shape web profile is
carried out to determine the strain gage locations sensitive to vertical and
lateral force. The strain gage locations used for measurement of lateral
force are having minimal effect of vertical wheel load and similarly,
strain gages for vertical wheel load are having minimal influence of
lateral load. The cross talk between vertical and lateral forces is kept to
the barest minimum while selecting the locations.
Wheatstone bridges are formed for vertical and lateral force measurement
channels. Measuring wheel supplied by Swede Rail has two vertical and
one lateral load sensing bridges per wheel. Sixteen strain gage locations
have been selected for vertical bridge with two gages per arm and twelve
locations for lateral bridge with three gages per arm. This means that in
one revolution of the wheel two vertical and one lateral value would be
obtained. Measuring wheel supplied by AAR has one position channel in
addition to above, which indicates the rail wheel contact point.
Output of channels is taken from slip-ring device fitted on axle end cap.
AAR measuring wheel-set has slip-ring device on both ends of the axle.
Swede Rail measuring wheel-set has slip-ring device on one end of the
axle. Output signal lead from left wheel to right wheel is transferred
through a hole drilled in the axle. This has been done to save the cost of
slip-ring device.
a. b.
Figure .7 a. Power Pack assembly ; b. Operator preparing wheel
16. 16
5. Air Brake Lab
The brake system it should have the following basic requirements:
Should be automatic and continuous i.e., at the event of train parting
brake should apply.
Shortest possible emergency braking distance.
Maximum possible brake force.
Shortest brake application time.
Shortest brake release time.
Low exhaustibility of brake power under continuous or repeated brake
application.
Minimum run-in and snatch action during braking
Types of brake system [6]
Vacuum brake
Single or Twin pipe graduated Air brake system
Electro-Pneumatic brake
Advantages of Air Brake System
It has higher rate of propagation.
It has shorter brake application and release time.
Brake fade does not take place, therefore, the train can be held on down
grade without any difficulty for a considerably longer period.
It has higher degree of reliability, controllability and maintainability.
Rigging is simple and entire equipments are lighter and required less
space.
Simple maintenance through calling for a higher degree of skill
Provide for higher operating speed.
Caters for smaller emergency braking distance.
Compressed air can be stored to higher-pressure differential.
Advantages of Electro-Pneumatic brake
Electric assistance is taken to control the B.P. Pressure with the help of
E2NV valve and core 9 cables.
E.P. valves are energized either for application or Release by a train line
circuit.
E.P. brakes are such designed that in case of failure, Air brake can be
applied to perform braking operation.
17. 17
The laboratory is equipped with a Test Rig having the complete pneumatic
circuits of 132 wagons and 30 coaches with twin pipe air brake system. Three
locomotive control stands can be used anywhere in the formation, with varying
compressed airflow rate up to 16 kilo litres per minute with the help of 7
compressors. Data acquisition and analysis is completely computerised. The
laboratory is equipped with a single car test rig and an endurance test rig for
distributor valves. Brakes are essentially meant for controlling the speed and
stopping of train.
Following activities are done in Air Brake Lab
Effects of changes in design of loco brake system on brake characteristics
of passenger & freight trains
Brake characteristics of freight & passenger trains with multiple loco
operation
Optimum location of locos in long freight train
Effect of changes in design of distributor valve on brake characteristics of
freight & passenger trains
Brake characteristics in case of train parting alarm chain pulling and
guard van application
Effects of leakage rates on release of brakes
Effects of over charge feature on train operation
Indication to driver in case of train parting
Performance and endurance testing of distributor valve
Performance testing of compressor of locomotive, EMU and DEMU
Performance testing of MERVCD
Calibration of pressure gauges, pressure transducers pressure recorder
and other pressure Measuring instruments of brake lab and other units &
labs of testing directorate and other directorates of RDSO.
Performance testing of EGTT (End on Train Telemetry system) on 38 &
116 Boxn wagon freight train.
Performance of APM (Automatic pressure regulating device) of Bogie
pressure regulating device of bogie mounting brake system.
Performance of ABU (Automatic Brake Unit) of anti-collision device in
26 coaches and 58 boxn wagon train.
Air Brake System
Single pipe graduated release air brake system is used in air braked wagons. The
main components of this system are :
Brake application stand
Distributor valve
Brake Cylinder
18. 18
Auxiliary reservoir
Control reservoir
Brake pipe and feed pipe
Flexible House Coupling
Rubber House pipe
Brake pipe which runs throughout the length of the train has air pressure at 5
kg/sq.cm. The compressed air is supplied by compressor /expresser in the
locomotive and the brake pipes of adjacent wagons are joined by using flexible
coupling. For application of brakes, the air pressure is reduced. The drop in
pressure being proportional to the braking effort required. The drop in pressure
is sensed by the distributor valve (DV) which allows compressed air from the
auxiliary reservoir into the brake cylinder and results in brake application
through brake shoes, release of brake taking place by normalizing by A-9and air
from the brake cylinder released simultaneously brake pipe pressure increased
up to 5 kg. The brake cylinder develops a maximum air pressure of
3.8kg/sq.cm.
During application of brakes the auxiliary reservoir gets disconnected from the
brake pipe. The auxiliary reservoir has capacity of 100 litres capacity whereas
control reservoir is of 6 litres capacity.
Figure .8 Twin pipe gradual release air brake system
5.1 Types of Air Brake System
Direct Release Air Brake System – AAR Standard[7]
In direct release air brake system, the release of brakes depends upon complete
build up of BP pressure. Since the pressure differential between brake pipe and
19. 19
the Auxiliary reservoir controls the both application and release, the release
pressure once initiated cannot be stopped except by reduction in brake pipe
pressure below AR pressure, which if resorted to frequently before the
Auxiliary Reservoir is charged fully, will results in the exhaustibility of the
brake system.
The main advantage of direct releaser system is that it has faster release
compared with the graduated release system. The addition of emergency valve
to the triple valve in the direct release system permits, a very rapid application
by venting the train pipe locally at every vehicle.
Graduated Release Air Brake System – UIC Standard[8]
In graduated release system, the Brake cylinder pressure varies according to
brake pipe pressure. The brakes are fully released when the BP pressure is fully
charged. The graduated release system is inexhaustible as the BC pressure is
related all times to the pressure in brake pipe, full release of the brakes being
obtained when brake pipe have been fully charged.
The main advantage of Graduated release system is quick release of brake
system and reduced release time. The graduated release brakes are considered
more suitable for passenger stock because of inherent smooth release function
promoting riding comfort.
The graduated release system conforms to UIC regulation, which lays down a
release time of 45-60 seconds. In the graduated release system the application of
the brake can be accelerated with brake accelerator valves which can be
attached to the main control valve.
5.2 Working Principle of Air Brake System[9]
In air brake system compressed air is used for operating the brake system. The
locomotive compressor charges the Feed pipe and Brake pipe throughout the
length of the train. The feed pipe is connected to the Auxiliary reservoir and the
brake pipe is connected to the distributor valve. AR is also connected to the BC
through DV. The brake application takes place by dropping the air pressure in
the brake pipe by the driver from locomotive by the application of A-9 valve.
Following three activities involved in this system:
Charging
Brake pipe throughout the length of the train is charged with the
compressed air at 5 kg/cm2
.
20. 20
Feed pipe throughout the length of the train is charged with compressed
air at 6 kg/cm2
.
Control reservoir is charged to 5 kg/cm2
.
Auxiliary reservoir is charged to 6 kg/cm2
in case of twin pipe and 5
kg/cm2
in case of single pipe.
Brake Application
For brake application, the brake pipe pressure is dropped by venting air from
driver’s brake valve subsequently the following action takes place:
The control reservoir is disconnected from the brake pipe.
The DV connects the AR to the brake cylinder and the brake cylinder
piston is pushed outwards for application of brakes
The AR is towards continuously charged from the feed pipe at 6 Kg/cm2
air pressure.
Brake Release Stage
Brakes are released by recharging brake pipe to 5 Kg/cm2
through the
driver’s A-9 brake valve.
The DV isolate the BC from AR.
The BC pressure is vented to atmosphere through DV and the BC piston
moves inwards.
Emergency Brake Stage
D-1Emerency valve under the driver’s seat to drop the BP pressure and
brakes are automatically applied.
S.No. Description BP pressure BC pressure
1. Release/ charging 5 kg/cm2
0 kg/cm2
2. Minimum Reduction 4.4-4.5 kg/cm2
0.8 kg/cm2
3. Full service 3.2 kg/cm2
1.8 kg/cm2
4. Over Reduction 2.5 kg/cm2
1.8 kg/cm2
5. Emergency 0 kg/cm2
1.8 kg/cm2
Table.2. Braking pressure at various position for coaches.
5.3 Air Brake System Test Rig
Air brake test rig is, with a facility for simulation of field condition for 132
wagon freight train & 30 coach passenger train with single and twin pipe air
brake system with data acquisition facility on 234 channels only. This test rig
has also facility to acquire data of BP, BC at every wagons on 58 wagons
freight train and for 30 coaches passenger train with BP, FP, BC, & MR on
three locomotive along with facility to measure air flow at four points on whole
21. 21
test rig. The test rig is designed to measure real time pressure in brake pipe,
Feed pipe, brake cylinders in coaches and wagons and BP,FP,BC,MR, and air
flow in three multiple locomotives on 234 channels data acquisition system with
a sampling rate of 100 sample per second during initial charging of brake
system and application and release of brakes.
The application software is in LABVIEW and Data Acquisition system is also
of National Instrument. The software is such that it can calculate the application
and release time of any intermediate coach/wagon with the help of 0.08%
accuracy (very high accuracy) GE Druck /Germany make pressure transmitters.
The exact flow of air is cross checked by flow meter connected in BP and MR
line. It can check the application and release time with flexible number of
coach/wagon connected with loco within the maximum limit.
a. b.
Figure .9 a. Air brake test rig*; b. EP assist brake test rig*
Test Perform
This test rig is being used to test the performance of brake valves and
equipments on the simulated train consist in stable condition to study on under
mentioned scopes.
Braking characteristics of freight train up to 132 BOXN wagon with
single and twin pipe system.
Passenger train up to 30 coaches with twin pipe system.
Effect of change in design of loco brake system on braking characteristics
of passenger and freight train.
Brake characteristics of freight and passenger train with multiple loco
operations.
Optimum location of locos in long freight train.
Effect of changes in design of distributor valve on brake characteristic of
freight & passenger train.
22. 22
Brake characteristic in case of train parting.
Effect of leakage rate on brake system.
Effect of over charge feature on train operation.
Optimum compressor & reservoir capacity for various train lengths.
Indication to driver in case of train parting.
Performance test of distributor valves.
Performance test of all valves and equipments of loco, coaches and
freight brake system.
Effect of EOTT on train brake operation.
Effect of Automatic Brake Unit of Anti-Collision device of locomotive
on Brake operation.
Figure .10 Schematic diagram of single pipe air brake system
Figure.11. Block diagram of twin pipe air brake system
23. 23
6. Fatigue Testing Lab
Railway components undergo large fatigue stress because of extreme working
conditions and loading. Newly designed bogie frames are subjected to stress
investigation and Fatigue Test. The object of these tests is to determine stress
levels, both in nature and magnitude, at different critical locations on the bogie
frame, by simulating static and dynamic loads likely to be experienced by the
bogie frame under actual service conditions. Also, the adequacy of the design of
the bogie frame, from structural strength point of view is determined by
applying dynamic load up to 6 or 10 million cycles, as the case may be, for
conducting fatigue tests and monitoring the stresses at different critical
locations.[10]
Both the wagon and coaches bogie frames are tested for higher numbers of
cycles which is calculated by Fatigue theory for better use of the components
and prevents its failure.
Following activities are done in Fatigue Testing Lab
Structural strength test of new designs of structures like Bogie frames,
Bolster, Brake Beam of railway rolling stock to check their design
adequacy by simulating different service and exceptional load.
Fatigue test of different components such as FRP sleepers , Rail Joints,
Shock Absorbers etc. by simulating service loads
Fatigue and load deflection test of different metal bonded rubber
components such as Elastomeric pads for Casnub Bogie of wagons ,
Rubber Buffer Springs, PU Side Bearer pads, Loco Side Bearer pads, PU
Side Bearer pads, Constant Contact Side bearer Pads by simulating
service loads.
6.1. 100 Ton Capacity Fatigue Testing System
To conduct general fatigue test on full scale structures a closed loop electro-
hydraulic servo controlled fatigue testing system of 44 tone capacity with
facility of testing full size structures simulated service condition was installed in
the fatigue lab of RDSO in year 1972. This system was procured from
MTS/USA. Then because of the capacity and design constraint a new 100 tone
capacity fatigue system was procured from M/s Instorn U.K. and installed in
fatigue lab in 1997.
Salient Feature of the system:
The test system basically consists of closed loop electro-hydraulic computerized
fatigue testing equipment. It is provided with two hydraulic power supplies for
generating high hydraulic pressure required for producing the desire forces. The
24. 24
high pressure hydraulic fluid at 210 kg/cm2
is fed to the hydraulic actuator to the
maximum rate of 500 LPM, through a servo-value. The actuator, which is a
cylinder piston arrangement, applies the compressive/tensile forces to the
specimen mounted on the test bed. The desired level of loading is achieved by
the controller in computerized control equipment of the system. A command
signal is fed to the input module which passes it on to a servo controller. The
desired dynamic wave form is provided by a function generator. The controller
sends electronic signal to the servo valve to regulate its port opening in such a
manner as to achieve the desired load level. A feedback transducer introduced
in the system, sense the load applied to the specimen and sends a proportional
signal to the input module. Here, the feedback is compared with the command
and any difference in their magnitudes or polarity is corrected through an
electronic signal to the controller. With this arrangement any continuously
varying command is reproduced faith fully.
The desire load is achieved through under mentioned set of dynamic actuators,
one 50 tone and three 35 tone capacity reaction frames mounted on rail type
slotted bed of 7.5m*14m size.
Figure.12. 100 tones fatigue testing machine with actuators*
Capabilities of system:
System can provide dynamic and static loadings on two axes simultaneously up
to a maximum load of 100 tonnes in combination of above mentioned actuators.
25. 25
System has facility to provide sine, square, haver-sine and triangle waveforms
of loading in dynamic mode.
Benefits:
Rolling stock components like bogie frame and bolster of Box- N wagons,
Coaches and locomotives, Side bearer pads, friction snubbers, brake beams,
buffer springs, elastomeric pads, upper and lower spring pads, bridge stringers
Composite material sleepers etc. are regularly being tested on this machine.
S.No. Type of
actuator
Quantity Capacity Stroke Frequency w.r.t.
Displacement
Remark
Displacement
in mm
Frequency
in Hz
1.
Dynamic
Actuator 4 25 tones
+-
50mm
2.5 10 Actuators can
work in tensile
& compressive
Mode
50 0.3
2.
Dynamic
Actuator 2 10 tones
+-
50mm
2 10 Actuators can
work in tensile
& compressive
Mode
50 0.5
Table.3.Specification of 100 tones Fatigue Testing Machine.
6.2. 500 Tones Capacity Structural
Before Sep-2010, Fatigue testing lab of Testing Directorate was equipped with
100 tones capacity fatigue testing system with a maximum of 25 tones load
actuators. This system was capable to cater the general fatigue testing
requirements of bogie frame and bolster of existing wagon with maximum axle
load of 22.82 tones. Towards the process of development of high axle load
wagons, RDSO now is in process to develop the higher axle load wagons as per
the AAR standards. The bogies and bolsters of higher axle load wagons are
supposed to clear the accelerated fatigue testing on 453 tones static and dynamic
loadings as per the AAR test criteria. Hence this system has been procured to
cater the future testing requirements for higher axle load wagons as per the
AAR testing parameters.
Salient Feature of the system:
This system is very high capacity equipment which can test the specimen up to
a load of 500 tones in static and dynamic modes. But it has been designed in
such a way that this huge system can be utilized for testing of smallest
26. 26
components of rolling stock under 0.5 tones also, for its optimum utilization.
The system is equipped with two hydraulic power units with six pumps of 100
LPM in each HPU to generate 3000 PSI hydraulic pressure on 1200 LPM
discharge rate to achieve the desire load through under mentioned set of
dynamic and static actuators and 500 tone capacity reaction frame on 10*10
meter ‘T’ slotted bed plate, which can bear 600tones load.
The test system basically consists of closed loop electro-hydraulic computerized
fatigue testing equipment. It is provided with a hydraulic power supply for
generating high hydraulic pressure required for producing the desired forces.
The high pressure hydraulic fluid at 3000 PSI is fed to the hydraulic actuator
through a servo-value. The actuator, which is a cylinder piston arrangement,
applies the compressive/tensile forces to the specimen mounted on the test bed.
The desired level of loading is achieved by the controller in computerized
control equipment of the system. A command signal is fed to the input module
which passes it on to a servo controller. The desired dynamic wave form is
provided by a function generator. The controller sends electronic signal to the
servo valve to regulate its port opening in such a manner as to achieve the
desired load level. A feedback transducer introduced in the system, sense the
load applied to the specimen and sends a proportional signal to the input
module. Here, the feedback is compared with the command and any difference
in their magnitudes or polarity is corrected through an electronic signal to the
controller. With this arrangement any continuously varying command is
reproduced faithfully.
Figure.13. 500 tones fatigue testing machine with actuators*
27. 27
S.No. Type of
actuator
Quantity Capacity Stroke Frequency w.r.t.
Displacement
Remark
Displacement
in mm
Frequency
in Hz
1.
Dynamic
Actuator 2
125
tones
+-
125mm
3 20 Actuators can
work in
compressive as
well as in
tensile mode
also
225 0.15
2.
Dynamic
Actuator 2 25 tones
+-
125mm
4 20 Actuators
can work in
compressive
as well as in
tensile mode
also
250 0.25
3.
Static
Actuator
4 75 tones 300mm Not applicable
Actuators
works in
compressive
mode only
Table.4.Specification of 500 tones Fatigue Testing Machine.
The other important features are as under:
Automotive test controller for controlling 8 actuators upgradable up to 32
actuators.
96 channel data acquisition system for on line stress recording.
T-slot bed plate of 10m*10m size which can bear dynamic load of 500
tones.
Four column portal frame of 500 tones capacity.
6-point concentrator of 600 tones capacity and 3 point force concentrator
for combined load application of multiple actuators.
Manual movement of ram of actuators through pendant.
Hydrostatic bearings have been provided in all the actuators to bear
maximum angular thrust.
Height of transverse beam can be adjusted through motorized lifting
device with laser beam safety monitoring system.
Heavy duty spring loaded roller clamp for easy sliding of cross beam and
actuators.
Following features make’s this system different form the 100 tone Instron
make old fatigue testing system
28. 28
This system can test the specimen up to 500 tones static and dynamic
load whereas old Instron machine is capable to test up to 100 tones only.
2. A wide range of testing can be accomplished on these heavy load
actuators with +-125mm stroke whereas max. stroke of Instron make
actuators are +-50mm.
Automotive test controller for controlling 8 actuators with smart wave
software capable of sequential loading between two to all eight actuators
on different load, different frequency and different phase.
Facility to provide different waveforms of loading: sine, square, ramp,
rounded ramp, haver-sine and triangle.
Facility to provide vertical loading, lateral loading and longitudinal
loading simultaneously in different phase, frequency and amplitude.
System can run in automatic mode on pre-programmed loading test
scheme.
96 channel data acquisition system for on line stress recording with auto
channel balancing and auto calibration.
Facility of simultaneous acquisition and real time display of feedback
channels (position & load) of actuators with stress value.
System to measure deflection up to 1 inch with accuracy of 0.001 inch.
Continuous running of the machine with feedback system through SMS
in case of any breakdown in the machine. This facility will reduce testing
time and manpower in other than general shifts.
Capabilities:
1. This system can test the specimen upto 500 tones static and dynamic loads.
2. Future heavy axle load wagons bogie, bolster and other components can be
tested as per AAR standards.
3. Load deflection test and energy characteristics test can be done on helical
springs and rubber buffer springs through the machine, since stroke of the
actuators are 250mm.
4. Calibration of CBC can be done in tensile and compression mode at 150
tones.
5. With the help of 96 channel data acquisition system on line stress recording
with auto channel balancing and auto calibration which shows directly stress
value. This reduces the testing time and analysis time of data.
6. T-slot bed plate provides lot of flexibility while mounting the test sample
under the actuators.
7. Two hydraulic power supply units each provided with six pumps with
automatic flow control to save the power i.e. No of motors in use will automatic
are selected by the system depending upon the oil flow requirement.
29. 29
Benefits:
Accelerated Fatigue Testing of Bogies & Bolster of high axle load wagons as
per AAR specifications. This Fatigue Testing Machine will help for design
validation of high axle load wagons i.e. 25t wagon & 32.5t etc. & other rolling
stocks (coach & locos) also by simulating field load conditions. This will also
help to improve the reliability of wagon bogie, bolster and other structure by
assessing the fatigue life of sub assembly.
6.3. Stress Measurements
The bogie is strain gauged at locations specified in the test scheme, which are
mostly linear gauges and a few three-directional Rossette gauges. Each gauge
(the arm in the case of Rossette gauges) fixed on the bogies frame, functions as
an active arm of Wheatstone bridge for monitoring the strain / stress. The
remaining three gauges required to form the Wheatstone bridge, called the
dummy gauges, are cemented on steel strips mounted on a junction box, kept
close to the bogie frame during the course of the tests. Terminals of the bridge,
thus formed, are connected to the recorder (visicorder).
During the stress recording in static condition, the bogie is subjected to the
desired load combinations and three sets of readings are taken for every load
combination. It is generally noticed that the difference between the three
readings is practically negligible. Before conducting the dynamic stress
measurement, the bogie frame is subjected to the desired load combinations for
at least for 3 to 5 minutes and thereafter, the readings are taken.
Fatigue Test
The bogie frame is subjected to fatigue test by applying dynamic load
combinations as per test scheme. The load application is of sinusoidal nature,
which is achieved with the help of the function generator available with control
panel of the fatigue testing equipment. Fatigue tests are carried out upto 10
million cycles. The test frequency, with the stabilised test set up, is achieved as
3 to 4 Hz. All the dynamic load actuators are applying load at the same
frequency and in the same phase.
Vertical Load Application & Reaction
The bogie frame is placed on the four vertical stools clamped with the test bed.
The loading is done with the help of load actuators, each with the capacity of
+10 or 25 t mounted on the two separate main reaction frames capable of
bearing 30 or 50 t force and located longitudinally on both the sides of test bed,
30. 30
through two loading beams placed at the ends of bolster which, in fact, is kept
on two specially designed steel tubes (in place of secondary springs) placed in
the spring seat guide located in the middle of the side frames.
Reaction of the vertical load at axle box location is attained through fabricated
steel tubes placed between the bogie frame and vertical stool at all the four
locations. Specially designed load cells, one each at all the four axle box
locations, are inserted between the stool and the steel tubes for equalizing the
load distribution.
Transverse Load Application & Reaction
A U-type clamp is mounted in the middle of the one of the side frames on the
existing bracket welded to the bogie frame. The transverse load is applied
centrally with the help of the +10 t capacity dynamic actuators, held horizontally
on the specially designed brackets mounted on the test bed. Transverse reaction
is taken at all the axle box locations by suitable reaction brackets clamped on the
test bed.
Tractive Load / Braking Force & Reaction
Longitudinal loads, simulating tractive / braking load and their reactions, are
applied on the bogie frame separately. For the purpose of braking force, loads
are applied simultaneously at four brake hanger locations, through two static
jacks in the upward direction, and through two pre-calibrated helical springs in
the downward direction. The tractive / braking loads are applied on the two
anchor links in the same direction through two static jacks mounted horizontally
on the two brackets, and their reactions are taken in the opposite direction at the
end of each side frame.
Visual Examination
Visual examination of the bogie frame is to be done regularly throughout the test
to check if any crack or deterioration in the bogie frame.
31. 31
7. Conclusion
During this Summer Training at RDSO Lucknow, I learned a lot about the
working procedure of testing of various components of IR which are Stresses in
wheel, Brake Blocks, Air Brakes, bogie frames for fatigue testing and come to
know about the use of technology for simulating and setting standards for the
components working and life through these research facilities. RDSO is one of
the prestigious organisations not only in India but in the World. There are many
technologies which are few in the world, and are available at RDSO Lucknow
for Research and Development are observed by me during this training. Practical
aspects of the working of components are gained through these training. This
training has also covered the research area in which the organisation is working
and through these training it will enhance our minds for utilizing our skills and
knowledge for giving better solutions.
This report is the outcome of time spends to learn through every source. I tried
to give my best effort on this trying to learn & compiled this report. But due to
time constraint it may be possible that I had left something which will be
covered in future through study and research.
32. 32
8. References
[1] http://www.rdso.indianrailways.gov.in/view_section.jsp?lang=0&id=0,1
[2] WELCOME TO RDSO CMS Team Last Reviewed on: 13-06-2012
[3]WELCOME TO RDSO CMS Team Last Reviewed on: 03-05-2011
[4] http://www.rdso.indianrailways.gov.in/works/uploads/File/publication_section.pdf
[5] “An Overview of the R&D Center of Indian Railways” by Wadhwa, Gopal Krishan
(September 2003)
[6] http://www.railway-technical.com/air-brakes.shtml
[7]https://www.aarpublications.com/Publications/Manual%20of%20Standards%20and
%20Recommended%20Practices.aspx
[8] http://www.uic.org/
[9] http://www.irfca.org/docs/brakes/brake-comparison.html
[10] A.Cera, G.Mancini, V.Leonardi, L.Bertini, “ Analysis of methodologies for
fatigue calculation for railway bogie frames”
[11]RDSO-Manual for testing & standards.
*Photographs courtesy by-www.rdso.indianrailways.gov.in
