On Tue, 26 Jun 2018 11:45:53 -0700 (PDT), John Leach
wrote:

It seem that some UK train are running slow as the warm weather is having an effect o the track.
How do other countries manage to run trains including High Speed when the weather is hot yet the UK cannot.
I have travelled on trains in Spain at the height of summer and there is no problems with heat affecting the tracks.

Rails are conditioned for the conditions that they are expected to
encounter. In the UK they're tensioned in to the extent that they can
survive all but the most extreme UK conditions; they do the same in
Spain. The only difference is that in Spain average temperatures are
higher. You say that there are no problems with heat affecting the
tracks. I bet there are, from time to time.

Coincidentally someone posted on SM this morning a view from the cab
of an Australian train rounding a curve to find itself on badly
buckled track. Another place with higher temperatures than here and
which routinely survices temperatures that would cause chaos in
Blighty.

It's not high temperatures that are the issue. It's temperatures
outside the normal range.