If by infrastructure, you mean trains, then the UK, like every other country uses rails appropriate to the average temperature.
"Network Rail said that its rails have a "stress-free" temperature of 27 degrees."
"Network Rail said that its rails have a "stress-free" temperature of 27 degrees."
In the US, the typical construction method is welded rail. AFAIK there is no allowance for expansion, at least on straight sections. Perhaps curved sections can move a bit to allow for expansion but move too much and the train goes off the tracks.