correct method of handling and stacking of rails
TRANSCRIPT
“Correct Method of Handling and Stacking of
Rails”
by Prem Prakash kumar, IRSE
ADEN/PKUS.E.Railway
The Rails, being the most vital component of track, require careful handling to achieve desired service life.
Any carelessness in loading, unloading, handling
and laying will not only contribute towards bad running but may cause bending, indentation or damage to the surface ,rendering the rails unserviceable and/or leading to premature failures of rails.
Handling
The use of higher UTS rails has been necessitated to meet the requirement of traffic.
Earlier 72 UTS rails were being used in track which were having less hardness and more ductility.
Due to less carbon content (0.45 to 0.60%), the hardness and UTS of 72 UTS rails was less and these were less prone to fracture.
Handling of 90 UTS and HHR
But with the introduction of BOXN wagons with cast wheels of higher hardness ,the 72 UTS rails were having alarming wear especially on curves.
To overcome this problem use of 90 UTS and 110 UTS rails started progressively. (carbon content in 90 UTS rails is 0.60 to 0.80%)
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90 UTS rails are less prone to wear due to more hardness but at the same time more susceptible to fracture.
90 UTS rails, being brittle in nature, are particularly susceptible to sudden fracture from locations of even minor dents /deformity. Hence lot of care has to be exercised in handling of rails at all stages.
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Barely visible straightness variations renders a rail unacceptable and require careful handling and stacking. Therefore,
Avoid Heavy static loading sudden impact Single point slinging Excessive end drop and flange overlap while
lifting or moving
Protection of straightness
DOs
Two point slinging for rails up to 13m length. Increase slinging point at the rate of 1 per 6.5m
Keep rails horizontal and straight while lifting/carrying/stacking
Rails to be kept in upright [head up] in straight alignment.
Provide suitable spacer/dunnage to protect rails against point contact.
The single point slinging increases risk of excessive bending and surface damage to the rails.
“The overhang beyond outer lifting point should not be greater than one half the distance between lifting points.”
Single point slinging to be avoided. Use two point slinging for rail up to 13 m.
Slinging Principles
RAIL LENGTH
(M)
NO. OF LIFTING POINTS
DISTANCE BETWEEN
LIFTING
MAX. RAIL END
OVERHANG (M)
12-13 2 6-6.5 3-3.2526 4 6.5 3.2539 6 6.5 3.25130 20 6.5 3.25260 40 6.5 3.25
Recommended locations of handling points for various rail lengths
Materials, whether new or old, lying along side the track is always a potential source of danger and efforts should be made to handle it as per best practices and laid down guidelines.
Instruction regarding unloading and stacking of P. Way materials on Cess have been laid down in Para 310 of IRPWM.
Arrangement for Placement of Rails along the track ,as per Drawing No. RDSO/T-8413
Placement of Rails on Cess along the Track
After unloading the rails care should be taken to ensure that there is no infringement and the rails are placed on firm base to eliminate the possibility of their sliding down due to vibrations and infringing the moving dimensions.
Same care should be taken for rails released from the works of rail.
For panel of larger length (say beyond 250 m), special care shall be taken to ensure that the panels do not buckle/distort and infringe the moving dimensions as a result of bad handling and stacking.
Use of Wooden Gutka [Multiple line Section]
TRR(P) [Wrong Practices]
Released Rail [Wrong Practices]
Surface notches of even less than 0.75 mm in depth are liable to cause rail fracture in service. Therefore,
Avoid
Impact or abrasion of rails against separators in wagons.
Round link chain slings for securing the rails.
Crossing or flange overlap while stacking or making rail bundles. Suitable spacers to be used while making rail bundles.
Any rail support, handling or clamping device and rail pinch rollers which apply localized or point contact to the rail.
Protection of Rail Surface
Dos
Where conventional slings are employed, use of fabric, e.g. polypropylene slings/sleeves is recommended. As an alternative, if flat link chains are used, these should be fitted with fabric sleeves.
Ideally, lift the rails by using electro-magnetic lifting devices
Rails are thermally very sensitive and are likely to develop metallurgical defects, if exposed to localized heating, which produces very hard, brittle metallurgical structures which may lead to sudden failure.
Avoid Heating, flame cutting, on or adjacent to rails.Contact with electric arcs and molten metal
splashes ,i.e. from adjacent welding operations . Early removal of mould , inadequate preheating
in welding operations.
Prevention of Metallurgical Damage
Rails withstand normal degree of rusting but localised corrosion pitting may cause subsequent rail fracture.
Avoid Contact with injurious substances which cause
high corrosion of steel , i.e. such as acids, alkalis, salts, fertilizers etc.
DOs Stack rails on well drained platform preferably
of concrete base as per Drg. No. RDSO/T-6219
Protection from contact with injurious substances
Avoid Overlapping of rail flanges Crossing of layers when dunnage is used Leaning stack by placing rail ends (rails of the
same length) in vertical alignment. Localised point or line contact loading in
stacking Criss-cross stacking of rails of alternative layers
as at right angle as far as possible
Stacking
DOsStack rails of same length [as far as possible] on
firm level base of well drained platform providing uniform support, as per Drawing No. RDSO/T-6219.
Each stack of the rail should of the same section and class.
Successive layers may be of the same or decreasing width for stacking of unequal length of rails.
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Subsequent layers should be separated with uniformly placed suitable spacers or dunnage in vertical alignment with base supports.
Place rails of shorter length in upper layers.
Use of suitable rail handling equipment, such as electromagnetic lifting devices, rail grips etc.
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Prevalent Practices of Stacking
CE Circular No.-246 & 181Para 254,255 & 310 of IRPWMRevised FBW Manual-2012Technical Diary-2014 CT-35:RDSO Guidelines for Handling and
Stacking of Rails
Reference...
Thank You