What is this on the wall below the platform?

[danny1962]

I notice these in the Kent area a lot.

plus.google.com/photos/110055669501444994025/albums/6002251242107708961?utm_source=chrome_ntp_icon&utm_medium=chrome_app&utm_campaign=chrome

They are always at a station, always at or near ground level, and only ever on the walls or pillars supporting the platform. The first photo in the album shows one close up, then the other photos show them in the context of the station itself.

In every case, there is an electrified 3rd rail present.

Can someone tell me please, What are they?

thanks

Danny

[yv47r]

Hi Danny, these are gauges that show the rail height relative to the wall and I believe they are used by the track engineers to ensure that the rail height does not vary too much especially in stations. If the rail height was too low for example the doors on a passenger train might be below the platform height, which would be very unusual. More likely that the rail height is too high and there would be a greater gap between the train and platform surface. Rail height will slowly drop in time and every so often the track may need to be raised up using a rail tamping machine which vibrates and raised the track up. So the gauges show the engineer what the height should be plus the distance from the platform edge to the nearest rail and maybe also the degree of cant at that point I think. I did have some closeup photos of one somewhere. They can be seen all over the UK mainland network at stations.

Cheers Paul