Mason is a tender engine from the United States.
Mason is based on the Central Pacific Railroad's 4-4-0 locomotive No. 60; the 'Jupiter' which made history as one of the two locomotives (the other being the Union Pacific No. 119) to meet at Promontory Summit during the Golden Spike ceremony commemorating the completion of the First Transcontinental Railroad.
The Jupiter was built in September 1868 by the Schenectady Locomotive Works of New York, along with three other engines, numbered 61, 62, and 63, named the Storm, Whirlwind, and Leviathan, respectively. These four engines were then dismantled and sailed to San Francisco, California, where they were loaded onto a river barge and sent to the Central Pacific headquarters in Sacramento, then reassembled and commissioned into service on March 20, 1869.
The Jupiter was not the engine originally intended to take the special train carrying railway officials to the ceremony, the railway initially selected its 'Antelope' locomotive to perform this duty. However, that engine was struck by a runaway log while enroute to the ceremony and was damaged such that the Jupiter had to continue the journey with the specials' coaches coupled behind its regular train (which the special had been following closely behind prior to the accident), proceeding to Promontory with only the special train upon reaching the end of its regular route.
In the 1870's, the engines' name was dropped, and it received a new boiler, funnel, and other upgrades, drastically altering its appearance. In 1885, the Southern Pacific Railway had acquired the Central Pacific, including the former Jupiter, and in 1891, the engine was renumbered as Southern Pacific no. 1195.
In 1893, the engine was converted to burn coal, and later that year was sold to the Gila Valley, Globe and Northern Railway, becoming that railway's number 1, operating as such until scrapped in 1909.
Full-size, operating replicas of the Jupiter and Union Pacific No. 119 were built in 1979 by O'Connor Engineering Laboratories for the Golden Spike National Historic Site at Promontory Summit, Utah.
A replica of sister engine, no. 63, the 'Leviathan', was built in 2009 by David H. Kloke's firm, Kloke Locomotive Works of Elgin, Illinois.
Mason has been slightly modified from his basis with buffers above his cowcatcher (which is flatter and shorter to acommodate them) and behind his tender, which also has a screw-link coupling.
Mason engine is painted blue, orange, and green with red and aqua lining.