Here's the power transmission you need
A J. Stone & Company (Deptford) Limited advert from February 1960 for their Stone-Maybach 'Mekydro' hydraulic transmission. The line drawing shows a D800 class loco which was fitted with two of these.
This advert appears in the following categories: Traction: Class 42/3 ; Supplier: J Stone ; Component: Misc Parts