Test sites are crucial for establishing the appropriate metal removal, profile and grinding cycle requirements for the railroad. They are used to establish the metal removal rate to control the growth of RCF cracks. Rail samples or non destructive methods are utilized to determine the fatigue-crack growth rates and their internal direction of propagation. The objective is to develop the optimal metal removal rate and the preventive grinding cycles to manage the rail grinding strategy for the changing railroad environment. Test sites are the best way to manage the risks of implementing changes to established preventive grinding cycles. If any serious failure of a new strategy takes place, it will happen in the test site. The data extracted through detailed monitoring of test sites can also be used to calculate the benefits of a modified preventive grinding strategy in controlling RCF, reducing rail wear, reducing grinding effort and cost.
Metal removal depends upon no. of stones, speed of grinding, characterstics of stone, metallurgy of rails and arrangement of stones
Rail Grinding Machine:A Basic approach
Head checks on Gauge Face of a Rail
Reduction in Rail/ Weld Failures
Action on two fronts
& Growth of Flaws
of the Flaws
Rail Grinding is an important track maintenance tool
Rail Grinding is the removal of metal from the surface
of the rail head
Through the action of a rotating grinding wheel
Mechanism used in rail grinding is cutting of metal
associated with formation of metal chips (and not
Corrective – Removing the defects in
Preventive Gradual – Removing the
defects in stages
Preventive – Removing the defects in
Also known as traditional Rail Grinding
To correct existing surface defects and the shape of the
head of the rail
A problem exists and sufficient grinding is done to
correct the problem
Defect is allowed to develop before taking up the
grinding; so remedial type action taken
At 20 GMT
Rail End Batter
Flaking and Shelling
New Rail requires grinding for removal of mill scale.
Mill scale is a very fine layer on rail head(<0.25MM).
Also known as profile grinding
Carried out before problems occurs
Rail head is ground to specific profile so as to improve
rail wheel contact interface
Carried out more frequently
This is periodic maintenance grinding carried out at
frequency decided on the basis of GMT.
Less aggressive grinding process
Removes fatigued material, surface cracks & improves
rail wheel interaction
Eliminates the need for defect correction grinding
Generally one pass process carried out at higher speed
ranging from 10 to 24 kmph.
In between corrective and preventive grinding
The defects in the rail are not removed in one go
Rails are ground at slow speed - only 1 to 3 passes are
In each round, the defects will taper down
Ultimately, we shift to preventive grinding
IR has adopted Preventive Gradual Grinding to start
Grinding cycle – 25 GMT –Ist, 50 GMT-2nd
One pass on straight and 3 passes in curve (speed 15-18
Metal removal 0.1-0.2 mm (approx.)
After I Cycle
Cracks Partly Removed
After II Cycle
(approx. 30 GMT)
More Cracks Removed
After III Cycle
(approx. 60 GMT)
Cracks Fully Removed
Reshaping Rail Head Profile - favourable Rail
Wheel Interaction reducing contact stresses
Removal of cracks in initial growth phase avoiding their propagation deeper
Shifting the contact of the wheels - away from the
Avoid Dip Formation at Welds - Reduction in
hunting by avoiding contact on misaligned welds
Increased rail life
Increased wheel life
Reduction in fatigue & surface defects
Less tractive resistance & therefore less fuel
Reduced need for rail transposing in curves, thus
saving cost on maintenance
Improved reliability of USFD testing
Test Sites -Selection
Why: For establishing
- Appropriate metal removal to control the growth of
- Target Rail profile
- Grinding cycle requirements
- Typical curvature / rail type
- Good access to track
- Rail history / defects
- No planned rail replacement
-Typical traffic & speed
- Away from Weld, Signal, LC etc
Gather data –MiniProf, surface photos, dye penetrate,
weld dips, hunting
Test Sites - MiniProf
• Mark rail location with
paint on field side for all
- Curve High, Low
- Track –UP, DN
- Date -automatic
- Gauge –automatic
• How it is decided?
• For IR, designed by NRC
• Four Profiles– CPC for DN road straight track & low rail of mild curve
– CPF for UP road and low rail of sharp curve
– HS for high rail of sharp curve
– HM for low rail of Mild curve
• Why two profiles for straight track?
Arrangement of stones across the rail and along the
Pattern needs to be selected by P. Way supervisor
trained in grinding
Purpose is to achieve target rail profile from existing
Factors affecting Metal to be removed
Straight Track – same as for old rail
For Curve Track – Mild Curve (< 1.25 deg)
High/ Outer Rail – Template HM – Pattern 2
Low/Inner Rail – Template CPC – Pattern 17
For Curve Track – Sharp Curve (> 1.25 deg)
High Rail – Template HS – Pattern 2
Low Rail – Template CPF – Pattern 24
For 52 kg Rail – For all conditions - 39
As suggested by GDMS
First cycle – 3 passes on both high & low rails
If GDMS gives 2 Passes – ask for alternative with 3
What to do if GDMS data has wrong direction of curve
The Grind Data Management System is an
integrated automatic data acquisition, data viewing
and analysis, quality control, reporting and rail
grinding planning tool.
The depth of cut w.r.t rail head and area of metal
removal for different patterns is not available with
IR to check the correctness of grinding.
The use of RCA in deciding the grinding pattern
and grinding depth is not yet established.
Calculation of metal removal/m is still to be
incorporated in GDMS.
Filling of Water to be done in night i.e during maintenance shifts.
The requirement of HSD oil from each RCD shall be arrived based on
the locations of RCD and the track to be ground and suitable
instructions shall be got issued from HQ to the respective RCDs.
While working of RGM, one track machine operator of the concerned
division having route learning of that section shall be deputed for
working as pilot and to assist in calling the signals.
When using the aggressive patterns as given by NRC, metal to the
extent of 1.5mm was removed.
On some occasions it is noted that the pattern entered in HMI are not
as per the grind plan due to operator mistake. This should be taken
A moped trolley with PA system, arranged to go ahead of RGM to warn the
gatemen, gang men working in section to keep at least 20m away from track
while grinding. The onlookers and vehicles at LC shall be warned to keep a safe
From each division, a PWI is nominated as grinding supervisor. His duties shall
To ensure the pattern fed into the HMI is same as suggested by NRC.
To ensure correct preparation of grind plan
To cross check the grind plan and grind history after grinding to find any
deviations in the patterns.
To take pre and post miniprof readings at test locations and to keep the
record as per proforma circulated by RDSO.
With experience, to check whether grinding is proper or not while
observing the pre and post grind profiles on GDMS and to suggest the
change in the patterns if required while grinding.
Identify the sections to be ground based on GMT, axle load
Establish test site locations and fill the RDSO proforma for
Identify stabling sidings at 50km apart, if not available
provide ( Provide only RL platform)
Identify the RCDs for HSD filling and make watering
arrangements at stabling sidings.
Issue JPO at HQ level and Divisional level for RGM
Obtain CRS sanction.
Prepare track database for input to GDMS
(Direction of curves shall not be w.r.t traffic direction
but w.r.t increasing chainage)
Works to be carried out Before Rail grinding
Knowing the Location/Sec where grinding is to be done.
Type of Rail and sleeper, joint type(LWR,SWR,FP), and
Location of SEJ, Points & X-ing, LC, Axle counter and any
other obstacle which may infringe the grinding.
Finding the location where grinding will not to be done.
Finalizing the Location where grinding Machine will be stabled
(where maintenance can be done).
Preparation of grind plan consisting of locations to be ground
with first pass patterns and depth of cut and details of
Clearing of rail head ballast to prevent damage to grinding
Painting of Curve starting and ending on sleeper with
white/yellow paint conspicuously.
Ensuring sufficient HSD and water for the day
Measurements and condition monitoring before grinding
Measure the rail profile at nominated test locations
with miniprof, Bar gauge, do DPT, take surface photos
and measure hardness.
while taking miniprof readings, the details such as
LH/RH of rail and TP to be fed otherwise it will not be
possible to identify the pre and post grind profiles.
Just Before the Grinding starts
Availability of complete & sufficient staff with
competency and Pilot with route learning
Moped trolley with PA system to warn Rly. staff and
onlookers and public at LC
Removing of axle counters by S&T staff
Job briefing consisting of
Location of work
Safety precautions to be taken
Head count and complete PPE
Allocation of duties with locations
First aid, Location of nearest hospitals and fire stations along the
Effective Communication system between crew, crew and station
Real Time Monitoring of Grinding Operation
on the vehicle
On the ground
Amount of metal removed
Profile of the rail achieved after each pass
Efficacy of the grinding motors
The Grind Data Management System is an integrated
automatic data acquisition, data viewing and analysis,
quality control, reporting and rail grinding planning
WATER SPRAY SYSTEM
RAIL SURFACE FINISH
Self propelled Diesel powered vehicle.
Can work in both directions.
Negotiate cant up to 185 mm.
Traveling speed 80 Kmph when self propelled and 100 Kmph in
25 kmph on 1 in 33 Grade
Speed with buggies down – 40kmph
Grinding Speed - 2.4 to 24 kmph
Can grind on a 100 m radius curve
Stopping Distance – 400 m from 80 kmph on a level track
Self propelled car
Pilot, Guard and T.I. to be provided by the division in
two shifts for first three months
10kmph @ 0.20mm
15kmph @ 0.13mm
Speed Cert to be issued and CRS sanction to be
Joint monthly prog. at zonal & weekly prog. At Divl
4 hours corridor block daily and 6 hours block on
weekends by SL working, trains cancellation/
Controller to allow RGM in the section following a
train to save time
Goods trains carrying highly inflammable material
like Naptha to be regulated on adjacent line during
Obstructions in the track
Passage of trains after the grinding block
Spark Guards of different designs
Water Storage – Front Control Car 20000 lit
- Water Tank 55000 lit
Water Pump – One 30hp 945 lit/min
Sleeper Spray – 2 Sets 7.6 lit/min
Ditch Spray – 2 Sets 100 lit/min
Water Cannons – 2 Sets 220 lit/min upto 31m
No. of Fire Extinguishers at different locations in the
Water to be arranged
Grinding stones for 600 hrs of working included with
RDSO to issue the specs and list of suppliers for
Zonal Railways to send vetted indents to COS every
Diesel to be provided by RCDs( Railway Consumers
COS to place order on oil Cos.
Sufficient fuel imprest to be created - 5 lakhs; this will
cater for other unforeseen expenses also
300m or 2X150m sidings at every 50kms
Connectivity at both ends
Lighting, watering, approach road and other facilities
to be provided
Lodging and Boarding of staff
Stabling either on unwired sdg or sdg should be with
OHE isolation system
Dust Collection System
Laser Based Rail Profile Measurement System on both
ends of the consist
LORAM’s Software – GDMS
- The software stores the data, analyses and compares
the data and works out the grinding efficiency
Recommendation of target profile, pattern and speed
in different passes to achieve the target profile