"The EMD DH1 was an experimental diesel-hydraulic switching locomotive built by General Motors Electro-Motive Division in May 1951. It was powered by a pair of small diesel engines suspended under the frame, driving through a pair of Allison torque converter transmissions to the inside wheels on each truck. These inside wheels were substantially smaller than the outside wheels on each truck."@en . "EMD DH1"@en . .