America Has a Hot-Steel Problem
theatlantic.com
theatlantic.com
Alternatively, rather than right angle cross-cuts they can do the acute slip-cut that allows the tracks to slip by each other --I think the main drawback is wear with these expansion joints.
The normal gapped joints lead to the clickity-clank and also have an issue with compaction of the railbed.
The problem is that the planet gets ever hotter and so the temperatures of 20 years ago (or more) are far below today's averages.