During World War II Union Pacific operated some of the most modern and powerful steam locomotives ever built. Among them were the famous "Big Boys," the largest steam locomotives in the world. Working with them were the "800-class" high-speed passenger locomotives, as well as hundreds of older class steam engines. The locomotives of the Mt. Washington Cog Railroad are examples of this type. 0-4-0: Four-coupled: 0-4-2T: 0-4-4T: Forney four-coupled: 0-4-4-0: 0-4-6T: Forney four-coupled: 0-6-0: Six-coupled: 0-6-2T: Several examples were built by Baldwin (25896,25953) for the Uintah Railroad. 0-6-2: 0-6-4T: Forney six-coupled: 0-6-6T: Forney six-coupled: 0-6-6-0: 1904,Baltimore & Ohio. The New York Central 999 steam locomotive and fuel car measure approximately sixteen feet tall, ten feet wide, and forty-eight feet long. The driving wheels are seven feet, two inches tall. The locomotive and fuel car weigh 124,000 pounds. The locomotive, with two driving wheels on each side,... Steam locomotives required constant maintenance from an army of skilled and unskilled workers, and the roundhouse is where that work took place. This roundhouse was built in 1884 in Marshall, Michigan, for the Detroit, Toledo & Milwaukee Railroad. Today it services the locomotives and equipment of Greenfield Village's Weiser Railroad. The most numerous steam locomotive type used in Hungary was the MÁV class 324 2-6-2, built from 1909 onwards, which were still at work in the last days of steam. The Hungarian State Railways (MÁV) also ran three important classes of 2-6-2 tank engines.