Yes SRS, Railroad tracks.

I think Greg Stephens title, "wrong kind of heat" is about an earlier time when the railways here blamed problems on something like "the wrong kind of snow".

Apart from knowing metal expands and contracts, I don't understand this one in as much as other countries have greater changes in temperatures over a year and do not seem to suffer this problem. How is track laid in the US for example where parts of it as normal will experience both colder winters and hotter summers than the UK?

BTW, I've yet to read any reports of track buckling. As far as I'm aware, train speeds have been reduced as a safety precaution.