A two 25kV system was featured in one of the issues of Railway Magazine earlier this year. I can't find my copy right now but I'll keep looking. If I recall correctly the system is used by the French on their high speed lines and will be used on the Channel Tunnel Rail Link in south eastern England. It is more a method of power distribution (rather than traction), cutting down on substations and voltage drops. The locomotives still use a single phase of 25kV 50Hz thus it is available for all types of existing stock.
When I find the article, I'll post an extract of the details here.
The Sishen iron ore line that runs from the interior of South Africa's Northern Cape to Saldana Bay uses an ultra-high voltage (for trains) of 50kV. This is to compensate for the almost complete lack of any infrastructure along it's route.
[This message has been edited by Hutch (edited 12-18-2002).]
