Union Pacific 588, a General Electric model C36-7 modified to C36M configuration; Houston, Texas, 2000. Click to enlarge.

(User:KLWhitehead, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons)



The Dash 7 Series is a line of diesel-electric freight locomotives built by GE Transportation Systems. It replaced the Universal Series in the mid-1970s, and was superseded by the Dash 8 Series in the mid-1980s.


All models of the Dash 7 Series are powered by a 12-cylinder or 16-cylinder, turbocharged, GE 7FDL 4-stroke diesel engine carried over from the Universal Series, and have speed-based adhesion control with a multi-channel LED annunciator panel.

Dash 7 Series traction motors are powered by direct current.

Construction history

The Dash 7's predecessor, the Universal Series, had been introduced in the 1950s, and with its innovative body structure, it had initially been greeted favourably by the market. However, GM-EMD had then developed the GP30 model to compete with it; GP30 production had commenced in 1961. Over many years, the GP30's reliability had given it a sales advantage, and when EMD introduced its successor, the Dash 2, in 1972, the Universal Series became completely obsolete. The Dash 7 Series was intended to redress the ensuing imbalance between the two competing manufacturers.

GE commenced production of the Dash 7 Series in 1976. By the time Dash 7 production ceased in 1985, about 2,800 Dash 7 locomotives had been built - roughly the same number of units as the total production of the Universal Series. By contrast, EMD built more than 8,000 Dash 2 locomotives.

Although the Dash 7 Series failed to surpass the Dash 2 in terms of market share, its 4-stroke engine returned better fuel consumption figures than the 2-stroke engine fitted to GM-EMD locomotives after the 1970s oil crisis. The Dash 7 Series was therefore positively received.


The naming of the Dash 7 Series, and that of its various models, is based upon wheel arrangement and power output. So, for example, "B30-7" designates a B-B configured 3,000 hp (2,240 kW) Dash 7 Series locomotive.

Four axle models

Common features
Specifications common to all Dash 7 Series four axle models are as follows:

AAR wheel arrangement: B-B
Prime mover: GE 12-cylinder V-type 7FDL12 or 16-cylinder V-type 7FDL16 four stroke diesel engine.



Type and origin

Power type: Diesel-electric
Builder: General Electric Transportation
​• AAR: B-B (B23-7, BQ23-7, B30-7, B30-7A, B36-7), C-C (C30-7, C30-7A, C36-7)
Gauge: 4 ft 8+1⁄2 in (1,435 mm), Brazil (?)
Length: 61 ft 2 in (18.64 m) (B23-7), 67 ft 3 in (20.50 m) (C30-7)
Fuel capacity: 2,100 US gal (7,950 l; 1,750 imp gal) (B23-7)
Fuel capacity: 3,000 US gal (11,400 l; 2,500 imp gal) (C30-7)
Prime mover: GE 7FDL
Engine type: 4-stroke diesel engine
Aspiration: Turbocharged
Cylinders: V12 or V16
Performance figures
Power output: 2,300 hp (1,720 kW) (B23-7, BQ23-7), 3,000 hp (2,240 kW) (B30-7, B30-7A, C30-7, C30-7A), 3,600 hp (2,680 kW) (B36-7, C36-7)
Operators: Various
Nicknames: 'B-Boat', 'C-Boat', 'Wheelchair'(Brazil)
Locale: North America, Brazil
Disposition: Most retired from service, some in service with regional and shortline railroads