Railroads on the Railways required tracks for the trains to run on them these tracks earlier made up of iron for its heavy duty but soon enough realise that iron was not a very good option for tracks. Meaning drawbacks of using iron for example rusting is it was realised that Steel was a better option in making railroads.
Steel being made out of iron is heavy duty material yet it is not much prone to rusting. Just addition of certain minerals and carbon in iron steel forging is done making it heavy duty material.
I researched this question and after the Romans were attacked by the Goths (a Germanic people) it went on to explain how the Slavs settled in Ukraine. I apologize if this isn't correct
