I’ve been introduced recently to the rich culture of those who maintain the railway infrastructure. I had always before regarded them as responsible only for all those ‘points failures’ which make me frequently late.
It turns out that there is a huge amount of skill and engineering insight required to cope with some of the weird and subtle physics that tracks can exhibit.
One such issue is to do with tracks which have vegetation growing nearby. If, in very warm weather, this shades one rail more than the other, the entire system of track, sleepers and ballast distorts locally -not what you want when trains are barrelling through at 100+ mph.
Cutting the grass/ferns/bushes manually is hugely costly and attaching blades to the trains might threaten public safety -to say nothing of the permissions required to chop down trees.
Sleepers are normally of uniform material over very long stretches of line. Today’s invention is therefore to fit a few trains with thermal cameras which can detect differences in rail temperature. This would then enable replacement of a few concrete or hardwood sleepers with steel ones, in areas found to suffer from differential shading.
It might be necessary to insert eg a copper* gasket between rail and sleeper.
This would allow more effective thermal conduction between the two rails and much more uniform track temperature (and geometry maintenance) but without having to re-lay large sections of track.
*Maybe not such a smart idea, given the possible electrochemical interactions ie rust?