Union
Pacific 4-4-2 Atlantic Locomotive
The Union Pacific is one of the group of railroads made up of the
Southern Pacific,
the Oregon Short Line, the Leavenworth, Kansas &
Western, the Oregon Railroad and Navigation Company, and the Chicago
& Alton, known as the Associated Lines. The Union Pacific have
recently obtained from the Baldwin Locomotive Works some 4-4-2 engines
of the 4-cylinder balanced type for fast passenger service. One of
these interesting engines was exhibited at the Master Mechanics'
convention at Atlantic City this year. The design conforms as far as
possible in detail to the common standards adopted by the Associated
Lines.
The engine is built with cylinders 16 and 27x28 ins. The high pressure
cylinders are inside and the low pressure are outside. The crossheads
are of the alligator type, while the inside ones run in four guide
bars. The main valves are of the piston type, 15 ins. in those of the
cylinders. The valve gear is the Walschaerts motion, actuated by cranks
on the main drivers.
The driving wheels are 81 ins. in diameter and are placed so close
together that their flanges almost touch. The driving wheel base is 84
ins. The rigid wheel base is 15 ft. 9 ins., which takes in the carrying
wheels at the back, while the total wheel base of the engine is 27 ft.
10 ins. The weights carried by the various sets of wheels are about
53,000 lbs. on the engine truck, about 46,000 lbs. on the carrying
wheels, and about 110,000 lbs. on the drivers, making an estimated
total weight of 209,000 lbs. With a boiler pressure of 200 lbs.,the
calculated tractive effort of this engine is about 28,400 lbs.,
(from a 1909 magazine, in the public
domain)