Why is the reason of shape of railway profile


Because of a question of MAB ( Mehmet ). i will try to explain some reason of railway profile shape
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Step 1:
For reasons of clarity in this picture point the principal parts of a railway track system.
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Step 2:
First of all, the section of the rail should be such that the load of each wheels is transferred to the sleepers without exceeding the permissible stresses. Several loads (dead) as the weight of parts and cargo items. Dynamic loads as centrifugal forces in a curve, inclined forces in a slope, and so on.
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Step 3:
The section of the rail should be able to withstand the lateral forces caused due to fast moving trains.The center of gravity of the rail section should preferably coincide the center of the height of the rail so that maximum tensile and compressive stresses are nearly equal. The web of the rail section should be such that it can safely bear the vertical load without buckling.
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Step 4:
The head of the rail should be sufficiently thick for adequate margin of vertical wear.The foot of rail should provide sufficient bearing area on the underlying sleepers so that the compressive stresses on the timber sleeper remain within permissible limits.
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Step 5:
The section of the rails should be such that the ends of two adjacent rails can be efficiently jointed with a pair of fish plates. ( joint bars)
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Step 6:
The surfaces for rail table and gauge face should be sufficiently hard to resist the wear. The contact area between the rail and wheel flange should be as large as possible to reduce the contact stresses.
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Step 7:
The foot of the rail should be wide enough so that the rail is stable against overturning.
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Step 8:
The fastener system to attach railway to sleepers explain the shape of the profile