INTRODUCTION OF
HIGHER AXLE LOADS
ON INDIAN RAILWAYS
Shiv Kumar
Director/IRICEN
Introduction of higher axle loads on IR

After experience of successful run of the pilot project
of running of CC+8+2 trains and introduction of axle
load of 22.82 t on IR since May,2005 on identified
iron ore routes, Hon. MR announced in his Budget
Speech ,06 that 25 T axle load trains will be
introduced on IR during the year 06-07.
 Initially ,two routes have been identified as under:
1.Dallirajahara-Bhilai
2.Banspani-Daitari
Indian Railways march towards
heavier axle loads
Universalise 22.82 t axle load on IR
 Construct Dedicated Freight Corridors
(DFC) fit for 30 t axle loads
 Feeder Routes To DFC to be strengthened
for running of 25 t axle load operations


Other routes identified for upgradation
for 25 t axle load operation
Proposed Axle Load &TLD for DFC
 Formation
& Bridges
: 30 t
 Track for DFC
: initially 25t
which can be upgraded to 30t
subsequently
 Trailing Load Density (TLD):12 t/m
Track Structure for DFC
For 30 t axle load
 68 kg (90 UTS or higher) Rails
 New Design of PSC sleeper, 1660/km
 E-clip elastic fastening with improved rubber
pads being developed by RDSO
 Flash butt welded joints
 Thick Web Switches and swing nose crossings
in turnouts
 PSC sleepers to be designed for turnouts ,level
crossings , SEJs, Bridge Approaches
Formation,gradients ,curvature for DFC

Formation width in embankment/cutting and centre to
centre spacing:
-Single Line 6.85 m (as existing)
-Double Line 12.35 m
- C/C spacing of DFC tracks 5.50 m
-C/C spacing of DFC from existing 6 m
 Suitable thickness of sub-ballast/blanket/reinforced
earth to be provided
 Curvature limited to 700m (2.5 degree)
 Ruling Gradient - 1 in 200 compensated
Proposed Loading Standards for
bridges on DFC
Loading Standards –Heavy Mineral loading
 Locomotives:
Axle Load
- 30 t
Tractive Effort - 60 t per loco for double headed
- 45 t per loco for triple headed
Braking Force - 25 t per loco
 Train Loads:
Axle Loads
- 30 t
Trailing Load Density-12t/m

MMD for
Dedicated
freight
Corridor
TRACK STRUCTURE FOR RUNNING 25T AXLE
LOAD TRAINS
As per Railway Board’s Track Policy Circular no.2
of 2006 dtd 19th July,06,the minimum track
structure for routes identified for running of 25t
axle load trains, to be adopted in all future track
renewals, construction of new lines, doubling etc.
will be as follows:
Rail Section……..……60kg 90UTS
Sleepers and density….PSC of existing design ,
1660 nos per km
Ballast cushion……….300mm
Points & crossing……Fan-shaped layout with
60kg curved switches
TRACK STRUCTURE FOR RUNNING 25T AXLE
LOAD TRAINS (contd.)

Existing track structure consisting of 52kg
90UTS rails on PSC sleepers with 1540 nos.
per km and 250mm ballast cushion may be
permitted for running of 25t axle load trains
at a restricted speed of 60 kmph, for BOXN
and similar type of wagons.
 In case of sidings, the minimum track
structure for 25T axle load operation will be of
52kg 90UTS rails on PSC sleeper with 1540
nos. per km and 250mm ballast cushion for
speeds upto 60 kmph. In cases where speed
is not exceeding 30kmph, track structure
comprising of 52kg 72UTS rails on PSC
sleeper with 1540 nos. per km and 250mm
ballast cushion will suffice.
TRACK RENEWAL FOR 25T AXLE LOAD
OPERATION (contd.)


52kg 90UTS rails will be replaced only
when they become due for renewal on
age-cum-condition basis.
Wherever the existing sleeper density
is 1540 nos per km, works for
increase in sleeper density alone will
not be sanctioned. These will only be
done as and when sleeper
replacement is required, either due to
age-cum-condition basis or to suit
higher rail section.
TRACK RENEWAL FOR 25T AXLE
LOAD OPERATION (contd.)

Where track renewal is sanctioned as 52kg 90UTS
rails and PSC sleepers with 1540 nos per km., the
sleeper density should be increased to 1660 nos per
km by Material Modification. Railways should,
however, start execution with the increased sleeper
density pending approval of MM estimate, to avoid the
delay. It however should also be ensured that MM gets
sanctioned within three months.
 Rail section should immediately be modified to 60kg
90UTS rails, wherever it is feasible. For other cases, it
should start within next 6 months. During this period,
preparatory work such as procurement of related
fittings etc. be ensured. Railway should also ensure
sanction of MM estimate within three months.
EXAMINATION OF EXISTING BRIDGES
FOR 25T AXLE LOAD (Feeder routes):



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Bridges have to be checked for 25 t axle load & trailing load
density of 9.33t/m.
Works already planned and awarded especially for
construction of bridges/rebuilding will be as per existing
loading standards( i.e. MBG)
Correction slip no 23 & 34 issued by RDSO no CBS/PSBC
dtd.21/23.03.06 ,CBS/PBR dtd.24/26.05.06 respectively
should be taken into account while checking the suitability of
existing bridges
Superstructure:
RDSO has examined on following premises:

Actual axle load and axle spacing for moving loads of
WAG9 locomotive and 25 T BOXN wagons.

Coefficient of Dynamic Augment (CDA) for limited speed
of 60kmph .
RESULTS
OF
ANALYSIS
superstructures of standard spans):
(for
SPEED POTENTIAL OF BRIDGES FOR DIFFERENT LOADING
STANDARDS OF EXISTING BRIDGES
STANDARD
SPAN(M)
BGML LOADING
Axle load
22.9T
TLD
7.67T/M
T. Effort
47.6T
RBG
LOADING
Axle load 22.5T
TLD
7.67T/M
T. Effort 75.0T
MBG
LOADING
Axle load 25.0T
TLD
8.25T/M
T. Effort
100.0T
1-20
60kmph
60kmph
60kmph
20-63
60 kmph
55 kmph
60 kmph
78.8
50 kmph
55 kmph
55 kmph
• Substructure:
Substructure analysis to be done case by case.
• Bearings:
– Bearings of standard spans designed for MBG
loading are fit for 25 T axle load.
– Bearings of standard spans designed for
BGML/RBG loading having spans 31.9m,
47.25m, 63.0m and 78.8m (all effective spans)
needs strengthening.
– One time inspection of Bearings apart from
schedule inspection to be done by Zonal
Railways for running of 25 T axle load.
15
Bridge Inspection and Monitoring

Following locations/members to be monitored as being critical from
fatigue consideration.





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Connection of cross girder with stringer.
Outstanding leg of the top compression flange of the stringer at its
junction with web rivet.
Rivets connecting bottom flange angle of the stringer with web at mid
span.
Vertical members at connection with top chords.
Rivets connecting bottom flange of cross girders with web at mid span.
Rivets of splice joints of bottom flange in plate girders.
Physical condition of bridges to be certified by Zonal Railways.
More intensive Bearing & Substructures Inspection to be done ( will
need more man power)
Directions for checking superstructure of non standard spans
including Arch Bridges etc., bearing of non standard spans and
substructure of all bridges issued to Zonal Railways.
Conclusions

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Experience of increased axle load on other major railway
systems in world has shown that Fatigue life of rail
comes down drastically with increase in axle loads and it
may take 5 to 10 years for heavy axle loads to tell its
effect on rails.
Rail grinding is required to be undertaken to prevent
Rolling Contact Fatigue and increase rail life.
The rail life obtainable under present axle load itself is in
range of 350-400 GMT which is way below the
prescribed life of 800 GMT for 90 UTS rails.
Till rail grinding is implemented, there is a need to safe
guard against rail fractures due to RCF by extensive and
effective USFD.
Fatigue life of rails also needs a review. Life of rails
subjected to heavier axle load needs to be realistically
brought down till grinding is introduced.
Conclusions


Installation of way-side vehicle condition monitoring
systems for identifying poorly performing wagons will go
a long way in reducing stress state of track by identifying
defective rolling stock and removing them from service.
These are:








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Wheel Impact Load Detector (WILD),
Truck Performance Detector (TPD),
Hot Bearing Detector (HBD),
Dragging Equipment Detector (DED),
Hot Wheel Detector (HWD),
Truck Hunting Detector (THD),
Wheel Profile Monitoring System etc
Development of track friendly bogie, self steering is
required.
Review after one more year of operation of 22.82t axle
load may help to firm up the position.