> This confused me because trains go "clack clack clack" - I guess that's foley now. They still seem to go clack clack on some bits. > When a track is made up

> This confused me because trains go "clack clack clack" - I guess that's foley now. They still seem to go clack clack on some bits. > When a track is made up from short rails bolted together, we leave small gaps between each one so that expansion doesn’t cause a problem. [0] They seem to use both long welded pieces and short gapped pieces, i'm guessing they are just selective where they use each. Anecdotally, trains seem to go slower on the clackedy clack bits... Speculation: I wonder if gapped sections are more resistant to failure IF they are used at slower speed? i.e long welded sections reduce maintenance at high speed; but gapped sections lack lateral temperature stresses, so IF they are used at a slow enough speed they could have very little stress. If so it's possible they use them on track close to stops, busy junctions, or track which is simply in a difficult area to carry out repairs on... essentially anywhere that track repair work will cause more problems than average and it's worth having slower trains on. Correction welcome. [0] https://www.networkrail.co.uk/running-the-railway/looking-after-the-railway/delays-explained/buckled-rail-and-summer-heat/ https://www.networkrail.co.uk/running-the-railway/looking-af...