USSR

Well, just when you think you're getting it covered someone passes on some gen: A link to a locomotive built by MAK in Germany for the former Soviet Union which was delivered in 1962. Engines were two MD655's driving two Voith L306 transmissions. The engines were set to 1500hp each. Presumably this locomotive was built as a demonstrator.

In an update to this, Phil Wormald discovered some details of this locomotive in a Russian book, written by V.A.Rakov. The locomotive described above was numbered "T300.01" and operated between 1962 - 1967. Quite what happened to it after that is not disclosed. Additionally, the book also revealed that Henschel built a larger hydraulic locomotive fitted with two MD870's and two K184 transmissions, which operated in the Soviet Union from 1963 - 1967. This locomotive was numbered "T400.01".

T300.01 touched up photograph (left) and schematic (right)

T400.01 touched up photograph (left) and schematic (right)