Barriers for progress

Britain's railways were built when labour was extremely cheap and when there wasn't much road traffic: so the solution when a railway had to cross a road was more often than not the installation of a gated level crossing, with a small cottage nearby in which the gatekeeper lived.

In the post-Second World War period, labour costs had soared and road traffic was growing frantically. The cost of manned (sic -- some of them were staffed by women from a very early age) level crossings was getting out of control.

One of the key solutions is seen in this sequence: the "automatic half-barrier crossing".

Based on pioneering work in the Netherlands and France, the AHBC was operated by the train itself passing over treadles built into the track.

I think the industrial design of these early models is quite delightful: the relationship between the barrier, the lighting unit and the central concrete pillar is very carefully thought out and aesthetically rather pleasing.

British Railways was relatively slow at introducing these AHBCs: idiot drivers caused a number of accidents in the early years and the safety regime around the barriers was made so tight that they ceased to be economic (one of the later rules involved them closing for so long before a train arrived that, on some routes, they had to remain closed almost permanently).

Later models incorporated an amber phase to the lights, and the "warbling" siren disappeared from most. They were an early attempt to automate the modern railway.