Diesel locomotive
Diesel locomotives offer significant operating advantages over steam locomotives. They can safely be operated by one person, making them ideal for switching/shunting duties in yards (although for safety reasons many main-line diesel locomotives continue to have 2-man crews: an engineer and a conductor/switchman) and the operating environment is much more attractive, being quieter, fully weatherproof and without the dirt and heat that is an inevitable part of operating a steam locomotive. Diesel locomotives can be worked in multiple with a single crew controlling multiple locomotives in a single train — something not practical with steam locomotives. This brought greater efficiencies to the operator, as individual locomotives could be relatively low-powered for use as a single unit on light duties but marshaled together to provide the power needed on a heavy train. With steam traction a single very powerful and expensive locomotive was required for the heaviest trains or the operator resorted to double heading with multiple locomotives and crews, a method which was also expensive and brought with it its own operating difficulties.
Lancaster and Chester Railroad
In 1946, the L&C upgraded its fleet by buying six diesel locomotives from the U.S. Army. These 65-ton Whitcomb locomotives had seen service in Italy during the war and burned about the same amount of oil to run that the old steam engines used for lubrication. The purchase of these engines made the L&C the first fully diesel-operated railroad in the state, something that Springs liked to boast of. The steam engines formerly used by the railroad were either sold or put out to pasture. However, these diesels did not spend long on the line as they were replaced by three 70-ton GEs in late 1950. Among the Whitcombs, number 51 passed to the Allegheny and South Side Railway where it would stay until the end of that property.