What Type Of Steel Is Used For Building A Railroad?

A web search for rail road rails reveals a type of steel known as Pearlitic steel

According to US patent number 6375763, this type of steel has better wear resistance than previously used pearlitic steel rail and sufficient ductility to prevent cracks due to thermal expansion and contraction caused by changes of temperature.

Your question isn't to specific pig iron is one,cast iron for the trucks/wheel carriages,steel for box cars,aluminum,stainless fuel container cars and food container cars for liquids.. Forged steel spikes for fastening down the tracks and so on...

For building rial roads the steel must be of good quality and it must sustain in a very high temperature.