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These have been in use for many decades, more so in some areas than others.
They are usually placed just into the start of the transition at the running in end of the curve. Or sometimes near the middle of a curve on a bi-directional / Single line.
The first photo shows the actuating button which is like a trigger on a grease gun. The second shows the disspenser where the grease comes out onto the rail gauge corner. The last photo shows the reservoir which contains the grease.
Although, im not sure if it's still there but Barnt Green station did have an 'iinnovative' a water based version to reduce the screaming of the wheelsets.
The old ones looked a bit like a car servo type can, mounted outside the track on the sleeper against the rail. Used to be common site on lines just before private works sidings, probably because of tight curves.