The ALCO Century 855 was a model of

diesel-electric locomotive A diesel locomotive is a type of railway locomotive in which the prime mover (locomotive), prime mover is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is conv ...

built in 1964 by the

American Locomotive Company The American Locomotive Company (often shortened to ALCO, ALCo or Alco) was an American manufacturer of locomotives, diesel generators, steel, and tanks that operated from 1901 to 1969. The company was formed by the merger of seven smaller locomo ...

for the

Union Pacific Railroad The Union Pacific Railroad , legally Union Pacific Railroad Company and often called simply Union Pacific, is a freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Paci ...

. The locomotive was notable for being ALCO's most powerful

and, at the time, the most powerful diesel locomotive ever built,"6,000 HP Diesel-Electric for Fast Freight Traffic in USA" ''

Railway Gazette ''Railway Gazette International'' is a monthly business magazine and news website covering the railway, metro, light rail and tram industries worldwide. Available by annual subscription, the magazine is read in over 140 countries by transport ...

'' July 3, 1964 pages 547-550 being surpassed by the

EMD DDA40X The EMD DDA40X is a 6,600 hp (4,943 kW) D-D locomotive, built by EMD from 1969 to 1971 exclusively for the Union Pacific Railroad. It is the most powerful diesel-electric locomotive model ever built on a single frame, having two 16- ...

in April 1969. The Century 855 was designed and built specifically for Union Pacific, which was in need of very high horsepower locomotives for its Overland Route through the Rocky Mountains. Despite its impressive power output, all three examples of the class were scrapped by early 1972 due to mechanical unreliability.

History

EMD DD35A The EMD DD35A, also known as the EMD DDA35, was a diesel-electric locomotive of D-D wheel arrangement built by General Motors Electro-Motive Division exclusively for the Union Pacific Railroad. They were a cab-equipped variant of the previous, ...

and the

GE U50 The GE U50 was an eight-axle, diesel-electric locomotive built by GE Rail. They were twin-engined locomotives, combining two diesel engines. Configuration The U50 rode on four two-axle trucks, grouped in pairs linked by span bolsters, giving ...

. The C855 rode on four two-axle

trucks A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construction ...

, grouped in pairs linked by

span bolster Span may refer to: Science, technology and engineering * Span (unit), the width of a human hand * Span (engineering), a section between two intermediate supports * Wingspan, the distance between the wingtips of a bird or aircraft * Sorbitan ester ...

s, giving a

wheel arrangement In rail transport, a wheel arrangement or wheel configuration is a system of classifying the way in which wheels are distributed under a locomotive. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and c ...

of B+B-B+B. The trucks and bolsters were similar to those under UP's earlier turbine locomotives. Only two

A unit A, or a, is the first letter and the first vowel of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''a'' (pronounced ), plural ''aes'' ...

s and one

B unit B, or b, is the second letter of the Latin-script alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is '' bee'' (pronounced ), plural ''bees''. It re ...

were built, all for the

, which had also requested double-engined locomotives from EMD and GE in order to replace the turbines, which had become uneconomical to operate. Union Pacific also wished to reduce the number of locomotives needed on a

consist In rail transport, a train (from Old French , from Latin , "to pull, to draw") is a series of connected vehicles that run along a railway track and Passenger train, transport people or Rail freight transport, freight. Trains are typically pul ...

, to keep in line with their allowable gross weight limit. By consolidating several locomotives into one or two, this allowed them to lower the axle load on the rails, but to stay within the limits placed by the company. They spent their lives in the general freight pool at

North Platte North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography. Etymology The word ''north'' is ...

; however, constant shutting down due to overheating & poor performance with its twin prime movers led to their early retirement and eventual scrapping by February 1972, after only being in service for less than eight years.

References

{{ALCO diesels Century 855 Diesel-electric locomotives of the United States B+B-B+B locomotives Union Pacific Railroad locomotives Railway locomotives introduced in 1964 Locomotives with cabless variants Scrapped locomotives Freight locomotives Standard gauge locomotives of the United States (Bo'Bo')(Bo'Bo') locomotives

History

See also

References