How do they avoid “clack-clack” sounds on high-speed trains? Are the rails made without gaps? And how do they manage thermal expansion then?

Question

How do they avoid “clack-clack” sounds on high-speed trains? Are the rails made without gaps? And how do they manage thermal expansion then?

In: 1047

Answer 1

I grew up on a farm bordered by two rails, one major freight one small line. I remember as a kid/teen when it was a cool night but then it heated up fast in the morning a sort of weird sound… hard to describe it. A bit like ice on a large lake cracking where it would start at one point then radiate out to the other side. It would start at one end of the line then echo down the rails to the other side. A booming bending iron under stress I suck at descriptors sound…

I had always assumed it had to do with some sort of temperature differential as the sun heated the cool rails. Was I right or was it some other rail phenomenon?