Maine Central Railroad Class W locomotives were intended for heavy freight service.

The last four designated sub-class W-2 (builders numbers 54564-54567) were delivered in 1914 and were 4,000 pounds (1,800 kg) heavier than the infobox figure.

Numbers 501 and 519 were officially property of the European and North American Railway (E&NA) as a condition of the lease of that company by the Maine Central Railroad.

They therefore avoided scrapping until Maine Central purchased E&NA to remove the lease obligation in 1955.

[2][3] When the Maine Central began purchasing diesel locomotives, road switchers were numbered in the 500 series previously reserved for the W class.