Dewi's Trains,
Trams & Trolleys

London Trams:
conduit hazards & oddities


Comments/corrections to: Dewi Williams

Oddities . . .

The conduit system had its own share of engineering peculiarities and problems.

[Bolt in conduit]

The size of the beams that formed the sides of the slot through which the plough passed were adequate for the time in which the system was designed. Post-WWII road vehicle loadings tended to deform the beams, narrowing the slot. Odd objects also could fall in the slot: my uncle was driving an elderly (even then, it was elderly) Austin through Wimbledon when he noticed people pointing at him and horns blowing. Apparently his brake cable had broken, and one end of the cable had dropped into the slot, intermittently making contact with ground and power in showers of sparks!

On the last day of trams in Clapham, a half-inch bolt dropped into the slot and was pushed along by a plough until it came to a narrow point, where it jammed. This photo shows the staff trying to get it out.

[Twin conduit]

The plough's freedom to slide side-to-side beneath the tram meant that the conduit did not have to be in the centre of the track. In one or two places where there was a short single track section, twin conduits in one track could be used to avoid having switches (points) in the plough's path, as shown in the rough diagram below.

On the other hand, the complete track consisting of running rails, slot beams, and conductor rails, was very rigid. In at least one instance, this was a useful feature: a tug-boat managed to ram a string of barges into Battersea Bridge, sever ly damaging it. In fact, the only thing stopping the span from falling in the river was the dual-track tramway. The bridge was at once closed to all traffic, and trams reversed just south of the bridge.

The tram in this picture is about to use the crossover (just visible beyond it) to reverse. The disconnected track in the foreground ran through a large wooden gate into a yard on the river bank. Originally, this was a siding for a permanent-way maintenance yard that was formerly on that site, and the crossover was used in conjunction with the siding.

The picture was taken on Dufaycolor film. This was an early colour process using the additive principle, where pictures were built up of dots of primary colours.

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This page last updated on 2004-12-10.