Posted on 02/12/2014

Photo taken on February  8, 2014


Big Boy
Union Pacific

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Union Pacific Big Boy

Union Pacific Big Boy
Note the “4-8-8-4” wheel arrangement printed just below the locomotive class number (4014). To the right of that is printed the driver diameter (68 inches) and the cylinder size (23¾ inches x 32 inches). The “540 MB” possibly refers to the weight on the driving, or powered, wheels (540,000 lbs.).

“Big Boy” is the affectionate name for American Locomotive Company’s coal-fired steam locomotives (manufactured between 1941 and 1944). Union Pacific operated them (for revenue) until July 21, 1959 (with coal from Union Pacific-owned mines in Wyoming). 25 were built and 8 have been preserved (with 7 of them inoperative and on display). But this one (number 4014, one of 20 built in 1941) was reacquired by Union Pacific and will be moved to Cheyenne, Wyoming for restoration and a conversion from coal to firing No. 5 oil. On its way it will stop in Las Vegas and Salt Lake City (having already stopped in Covina, California after it left the RailGiants Train Museum in Pomona, California). It was originally retired in December 1961 (having traveled 1,031,205 miles).

The “Big Boy” was designed to improve the efficiency of the rail line between Green River, Wyoming and Ogden, Utah (over the Wasatch mountain range). It eliminated the use of both “doubleheading” (using two locomotives at the front of a train) and the delays involved with adding and removing helper engines. Because of its great length (over 85 feet) the frames of the “Big Boy” locomotives were hinged (articulated) to allow them to negotiate curves. Minus the tender, the “Big Boy” had the longest engine body of any reciprocating steam locomotive.

• Length: (locomotive) 85 feet 3⅓ inches (25.99 m), (overall) 132 feet 9¼ inches (40.47 m)
• Width: 11 feet (3.4 m)
• Height: 16 feet 2½ inches (4.94 m)
• Weight: (locomotive and tender) 1,250,000 lbs. (566,990.5 kg)
• Gauge: 4 feet 8½ inches (1,435 mm) standard gauge
• Wheelbase: 22 feet 5½ inches (22.09 m)
• Fuel Capacity: 28 short tons (25 long tons, 25.401 metric tons)
• Water Capacity: 25,000 US gal (95,000 L)
• Top Speed: 80 mph (130 km/h)

Union Pacific rail yard, 19100 Slover Ave., Bloomington, California

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