ALCO Century 855

ALCO Century 855
Union Pacific Railroad 61
Type and origin Power type Diesel-electric Builder American Locomotive Company (ALCO) Serial number 84730–84731 (A units), 84732 (B unit) Model DL855, DL856 Total produced 3 (two A units, one B unit)
Specifications Gauge 4 ft 8 1⁄2 in (1,435 mm) Length 86 ft (26.21 m) Loco weight 551,400 pounds (250,111 kg) Fuel capacity 6,000 US gal (5,000 imp gal; 23,000 L) Prime mover Dual Alco 251C Engine type Dual V16 diesel Alternator AC alternator Traction motors DC traction motors Cylinders 32 (2 x 16) Transmission Electric
Performance figures Power output 5,500 hp (4,101 kW)
Career Operators Union Pacific Railroad Numbers 60–61, 60B Locale North America Delivered July, 1964 Disposition All scrapped
Stats given in this table pertain to cab unit

Type and origin
Power type	Diesel-electric
Builder	American Locomotive Company (ALCO)
Serial number	84730–84731 (A units), 84732 (B unit)
Model	DL855, DL856
Total produced	3 (two A units, one B unit)

Specifications
Gauge	4 ft 8 1⁄2 in (1,435 mm)
Length	86 ft (26.21 m)
Loco weight	551,400 pounds (250,111 kg)
Fuel capacity	6,000 US gal (5,000 imp gal; 23,000 L)
Prime mover	Dual Alco 251C
Engine type	Dual V16 diesel
Alternator	AC alternator
Traction motors	DC traction motors
Cylinders	32 (2 x 16)
Transmission	Electric

Performance figures
Power output	5,500 hp (4,101 kW)

Career
Operators	Union Pacific Railroad
Numbers	60–61, 60B
Locale	North America
Delivered	July, 1964
Disposition	All scrapped

The ALCO Century 855 was ALCO’s most powerful diesel-electric locomotive and, at the time, the most powerful diesel locomotive ever built.

Powered by a pair of 16 cylinder ALCO 251C diesel engines, and rated at 5,500 hp (4,101 kW), it was ALCO's answer to the EMD DD35 and the GE U50. The C855 rode on four two-axle trucks, grouped in pairs linked by span bolsters, giving a wheel arrangement of B+B-B+B. The trucks and bolsters were similar to those under UP's earlier turbine locomotives. Only two A units and one B unit were built, all for Union Pacific Railroad, 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, 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; however, poor performance led to their early retirement and eventual scrapping by February 1972.

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