Retired Georgia Northern Railway No. 2, a Fairbanks-Morse Model OP800 railcar.

(The original uploader was Can't Undo at English Wikipedia., CC BY-SA 3.0 <>, via Wikimedia Commons)



The OP800 was a lightweight, streamlined railcar built by the St. Louis Car Company in 1939. Fairbanks-Morse supplied the 800 hp (600 kW), five-cylinder 8 in × 10 in (203 mm × 254 mm) opposed piston engine prime mover. The units were configured in a highly unusual 2-A1A wheel arrangement (later converted to 3-A1A) mounted atop a pair of road trucks, and equipped with a front swing coupler pilot. The aft section was divided into two separate compartments: one was used to transport baggage and the other served as a small railway post office, or RPO (the forward door, located just behind the radiator louvers, was equipped with a mail hook).

Six units, accompanied by matching trailing car sets, were manufactured exclusively for the Southern Railway. Two were later sold to the Georgia and Florida Railroad and Georgia Northern Railway as maintenance cars. The remaining four OP800s were scrapped in 1955; selected parts were retained for maintenance use on other SR F-M motive power.

At least four of these cars had individual names applied to them, including "Vulcan", "Cracker", "Joe Wheeler", and "Goldenrod".

No OP800 units survive.


Southern Railway FM OP800 No. 4 "Cracker".

(W. Lenheim Collection, C.S. Archives)


FM OP800 Overview

Type and origin
Power type: Diesel-electric
Builder: St. Louis Car Company
Model: OP800
Build date: 1939
Total produced: 6
​• AAR 2-A1A (as built); later 3-A1A
Gauge: 4 ft 8+1⁄2 in (1,435 mm) standard gauge
Length: 80 ft (24.38 m)
Prime mover: FM 5OP 38F-5-1/4-5
Engine type: Opposed piston 2-stroke diesel
Aspiration: Roots Blower
Generator: Westinghouse DC
Traction motors: DC
Cylinders: 5
Cylinder size: 8 in × 10 in (203 mm × 254 mm)
Transmission: Diesel-electric
Locomotive brake: Straight air
Train brakes: 6-ET Air
Performance figures
Maximum speed: 80 mph (130 km/h)
Power output: 800 hp (600 kW)
Operators: Southern Railway, Georgia and Florida Railroad, Georgia Northern Railway
Locale: North America
Disposition: All scrapped


An FM OP800m Motorized Railcar of the Georgia Northern Railway.

(W. Lenheim Collection)