Is this where Hornby got the idea for their 'Live steam' models? I'm just glad that it doesn't need that many KV to work the Hornby models!
The earliest AC systems in the UK used 25Hz power, half our current frequency of 50Hz.
I suspect the low frequency was the result of early generating technology. The first generators were driven by reciprocating steam engines, not turbines, and the larger the engine the slower its top speed. Parson's steam turbine came in around 1890, I think, and it it took some time to develop the technology to make turbines big and fast enough to drive generators at 3000rpm to give the 50Hz power.
Regards,
John Webb