[outpostinmass2]

The switch to Diesel was held off during WWII delaying the switch. Infrastrucure support for steam is what was turned off almost overnight. Coal and water stations were all shutdown within ten years. Steam trains had no where to go.

[SoCal Pubbie]

Successful diesel models were introduced in 1925 with the three boxcabs units sold to the Jersey Central, B&O, and Lehigh Valley roads. Between then and 1942 a host of new models were delivered to the roads. WWII did slow down the production of diesel units, but steam engines were produced through 1949. The Santa Fe regularly scheduled steam power on the San Diegan until 1953, and used the old horses as backups on the line until 1958.

The last standard gauge class 1 regular service steam engine served in October of 1962. If 37 years can be considered overnight, I guess I'll agree.