[1] It can involve replacing an internal combustion engine powered by petrol (US: gasoline) fuel with an engine powered by diesel fuel, as occurred on a large scale with trucks, buses, farm tractors, trains, and building construction machinery after World War II.
Weighing against the cost of, and inertia against, replacing the large investment that railways had in existing steam power were the dramatic increases in flexibility and efficiency with diesel.
Diesels can be parked running for days unattended, whereas steam engines must be constantly tended to if not completely shut down.
Bringing a steam engine boiler up to operating temperature is often regarded as both an art and science, requiring much training and experience.
The range of efficient operation for diesels under different speeds and grades is much greater than with steam locomotives, which tended to be purpose-built for specific situations.
Dieselization could be accomplished without any major changes to rail infrastructure, presenting lower initial capital costs than electrification.
However, in situations where volume is sufficient to amortize the capital costs of electrification, the greater efficiency and speed available with electrification are significant advantages and electrified systems are favored throughout most of the developed world, with the most salient exceptions being North America, the British Isles, and Australia.
[citation needed] Relatively short trackage between destinations and high traffic volumes in Europe favoured electrification to replace steam.
[citation needed] In Britain the Great Western Railway introduced diesel railcars in the 1930s and the first British mainline diesel locomotive was built by the London, Midland and Scottish Railway in 1947, but unlike elsewhere in the developed world, the transition away from steam was delayed during the early postwar years.
Steam continued on many industrial railways in the UK mainly with the National Coal Board And British Steel Corporation until the 1980s.
The first ALCO boxcab switcher was put in operation in 1925 by Central Railroad of New Jersey at its 138th Street[6] waterfront terminal in The Bronx.
Dieselization got a boost from three developments of the early 1930s: the development by General Motors and its Winton Engine Corporation subsidiary of diesel engines with vastly improved power-to-weight ratios and output flexibility; the desire of railways to find more cost-efficient locomotion for passenger service at the height of the Great Depression; and design innovations in rail equipment that reduced weight, making the contemporary diesel engines, which were low-powered by today's standards, viable for mainline passenger service.
The mid-1930s saw the introduction of lightweight diesel-powered streamlined trainsets such as the Burlington Route's Zephyrs and Union Pacific's M-1000x "City" trains.
During the second half of the decade, diesel locomotives with sufficient power for full-size passenger trains were developed and put into regular production.
Mechanical coal stokers, in use since the 1920s,[9] and use of bunker oil as an alternative fuel, facilitated the practical use of steam for the highest power requirements.
Locomotive size became an issue, as steam engines became so big in the 1940s that the cylinder and boiler dimensions were pushing the limits that the loading gauge would allow.
[10] The drop was most precipitous in passenger service, where modernization of equipment was imperative for image and cost reasons as railroads faced increasingly stiff competition from airplanes and the automobile.
People were no longer content to endure the large amounts of soot and smoke that coal burning steam engines produced.
Steam engines lasted well into the late 1950s on major American railroads, and in isolated cases into the middle 1960s on small common carrier roads.
[citation needed] Soviet leadership in the 1920s and 1930s had originally envisioned railway electrification as a key component of their industrialization, but by World War II only a small portion of their rail lines were electrified.
Their project faced many challenges, including the high initial costs of electrification relative to traffic volume on long rail lines, high resource costs of early Soviet electrical power generation, and the urgent need to repair wartime damage to rail and power systems throughout eastern Europe.
In spite of this, more desolate railway lines, particularly on the northern island of Hokkaido continued to use surplus steam locomotives well into the mid-1970s.
This was due to the limits and problems created by the then-nationalized rail network, Japanese National Railways (JNR).
[needs update] The state-owned Manila Railroad Company (MRR) began its experimentation with gasoline and diesel fuel in the 1930s.
[citation needed] In London the famed "hackney carriage" taxi has long been powered by a diesel engine.
Rising gasoline prices during the 1970s spurred interest in diesel for passenger cars, although it soon faded in popularity for private vehicles other than pickup trucks.