well above the level of the driving axles. The motor or motors drove the jackshaft or jackshafts through gears or side rods, and then the jackshaft turned the wheels through side rods. In Europe, Oerlikon and Brown, Boveri pioneered a variety of jackshaft designs, while in the United States, Westinghouse was dominant. The early surveys of electric locomotive designs cited here all use the term jackshaft or jack-shaft. Examples include the PRR DD1 and FF1 electric locomotives, as well as the Swiss Class Ce 6/8 Crocodile and its narrow-gauge cousin, the Rhaetian Railway Ge 6/6 I. Continuing development of electric motors made them smaller, and by World War II, most new and made jackshafts obsolete. Internal combustion locomotives When Baldwin first began building internal combustion locomotives in the first decades of the 20th century, they used a 2-speed transmission from the gasoline engine to a jackshaft. Baldwin's early internal combustion locomotive patents covered the use of both side rods and chain drive to link the jackshaft to the driving wheels. The first Baldwin internal-combustion locomotives used an 0-4-0 configuration and weighed from 3.5 to 9 tons, but by 1919, a 25-ton 0-6-0 configuration was available. These locomotives saw extensive service on the narrow gauge trench railways of World War I. The British Rail Class 03 diesel (pictured) is a more recent example. Jackshafts were used on some diesel-mechanical and diesel-hydraulic locomotives but were seldom used on diesel-electrics. One exception was the British Rail Class D3/7. Suspension movement A difficulty with coupling rod drive from a jackshaft is the need to allow for vertical suspension movement of the axles. Several mechanical arrangements have been used to allow this. Long horizontal rods The simplest arrangement is to use long coupling rods, running horizontally. A large vertical movement at the wheel end gives rise to only a small horizontal movement at the jackshaft drive. For a diesel-mechanical locomotive this can be compensated for by horizontally compliant mounting of the transmission. The heavy engine is carried over the drive wheels for adhesion weight, but the relatively lightweight gearbox can be mounted at one end, beyond the coupled wheelbase. A final drive casing is also narrow enough to mount between the frames, allowing it to be mounted low down and level with the driving axles. This arrangement is common for slow speed diesel shunters, but not usually for main line speeds. The Swedish D-lok of