A unique- and apparently lunatic- locomotive scheme was to generate steam by electric heating. This appears to make no sense; having gone to all the trouble and expense of electrifying a railway line, to use the power to run a steam engine with its less-than-impressive efficiency, rather than simple electric motors, seems demented.
It was not. There was (as usual) a good reason.
| Left: One of the Swiss electric-steam tank engines.
The Swiss Federal Railways had a highly electrified system during the Second World War, but retained little 0-6-0 tank engines for shunting. Due to war conditions coal was in short supply, but hydro-electricity remained plentiful. Therefore some of these small steam locomotives were converted to raise steam by electric heating. Power was taken at 15 kV, 16.6 Hz* from overhead lines by a pantograph, and fed to resistance heating elements in the boiler, via two transformers rated together at 480 kW. Water feed was by normal steam injectors. These unique locomotives also retained the capability of being fired by coal in the usual way.
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* Presumably there was a compelling reason to distribute power at such a low frequency, but despite various suggestions, the matter remains obscure, to me at least. One obvious objection to 16.6 Hz distribution is that all the transformers would be three times the size.
| Left: Another view of the electric-steam tank engine.
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| Left: And another view. The chimney seems to have been extended in this photo.
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| Left: This is engine E 3/3 pictured in 1942.
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| Left: This was clearly taken at the same time as the picture above.
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