French Technical Advance in the Field of Diesel Railway Traction

Diesel locomotives on the French National Railroads, intended to haul heavy-freight trains as well as fast passenger trains on difficult profiles with numerous stops, have: a massic power at the rim above 30 hp per ton, a load per axle below 21 tons, a coefficient of adhesion at starting always above 0.33, a dynamic stability close to 3 km/hour, and trucks with short turning radius.

These locomotives are almost universally diesel-electrics equipped with 4-stroke diesel engines supercharged with aftercooling. These engines are either semi-rapid (rated at 2700 hp) for the 12-cyl type or rapid (1500 rpm, rated at 2400 hp) for the 16-cyl type.

This paper discusses the development of these engines and the French railroads experience with them.