smallspy
Senior Member
What do you think supports the rails?Underneath the trains I get (i.e. the running rails, trackbed and to a lesser extent the 3rd rail), but why would the other infrastructure around the trains require strengthening, if the trains generally don't make contact with anything else besides the tracks & 3rd rail?
That weight and those forces need to go somewhere. They don't just disappear into the rail, ties, trackbed, etc. This is less of an issue in most of the tunnels because of the way that they interact with the soil, but it may be a serious issue at things like bridges. Plus, not all of the "tunnels" are actually tunnels.
Dan