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

The rails are welded together so there are no gaps.

But they still need to be able to expand, there are a few options:

Expansion joints: https://en.wikipedia.org/wiki/Railway_track#mediaviewer/File:Expansion_joint,_Hayle.jpg

Anchoring the rails so they can’t move. The rails are stretched and then anchored to the ties. Since they are already stretched, they don’t expand when heated. In cold weather the rails may need to be heated, so they don’t shrink too much.

Rails used to be short, 20 m (66 ft). So you got the clack clack a lot.

Now they are much longer, 400 m. So even if not welded, much less joints.