Is the track T or I-beam?
In the upper rail, the layer and is contacted with a wheel, is adding another metal, indium, it added to the rail on the part of the hardness of the case, even has some toughness, the train wheel is very important, it and the "tire" contact, collision and there will be some flexibility, to ensure the safe operation of the train.
If >13% is added to manganese and made into high manganese steel, it becomes hard and tough. So people use manganese steel to make wear-resistant machine parts and rails, bridges and so on.
The track is made of track steel.The rail is made of high manganese steel. Manganese iron is very eccentric and interesting: if 2-3% manganese is added into the steel, the resulting low manganese steel is as brittle as glass and cracked at one stroke.
