The Chesapeake & Ohio's M1 No. 500, pre-delivery. Click to enlarge.

(Baldwin Locomotive Works, via W. Lenheim Collection)


Baldwin logo.
C&O logo.


The Chesapeake and Ohio class M-1 was a fleet of three steam turbine locomotives built by the Baldwin Locomotive Works for the Chesapeake and Ohio Railway in 1947–1948 for service on the Chessie streamliner. As diesel locomotives became more prevalent following World War II, the C&O was one of several railroads that were reluctant to abandon coal as a fuel source, and saw steam turbine technology as a possible alternative to diesel. At the time of its construction it was the longest single-unit locomotive in the world.


A C&O M1 prepares for a test run.

C&O Publicity Department, Public domain, via W. Lenheim Collection.



The design of the M-1 was a collaboration between the C&O, the Baldwin Locomotive Works and Westinghouse.  The C&O possessed substantial coal-hauling revenue and was loath to abandon it as a fuel source.  Further, C&O's engineering staff expressed concern that oil reserves would be exhausted within 25-30 years.  The locomotive contained a single Westinghouse turbine which in turn drove four direct current (DC) generators, mounted in pairs. Each generator produced 1,000 kilowatts (1,300 hp), and the four generators collectively turned eight traction motors.

Defying the usual convention, the M-1 was arranged with its boiler in the rear and the coal bunker in the front. The turbine-generator system meant that the M-1 contained no cylinders. The reduced number of moving parts meant that, in theory, the M1 required far less maintenance than a conventional steam locomotive. Its designers predicted that it could make a round trip between Washington and Cincinnati without servicing.

The locomotive's throttle included eleven settings, ranging from one (idling) to eleven (full speed). The locomotive's cruising speed was 70 miles per hour (110 km/h), at which point the throttle was on "seven." During a trial run with a reporter from Popular Mechanics aboard, a C&O engineer expressed his dissatisfaction with a local speed limit of 75 miles per hour (121 km/h), noting that he would "sure like to be able to pull it back to eleven! Not including research and development, the three locomotives cost US $1.6 million.


Chesapeake and Ohio M1 No. 500 at the Chicago Railroad Fair in 1949. Click to enlarge.

(Joe+Jeanette Archie, CC BY 2.0 <>, via Wikimedia Commons)



The C&O cancelled the Chessie in 1948, before it ran in revenue service, depriving the M-1s of their reason for existence. The M-1s themselves proved expensive to operate and mechanically unreliable.  According to one source, the M1s never made a single trip without breaking down. They spent their short careers operating between Clifton Forge and Charlottesville, Virginia.  The locomotives were scrapped in 1950.


Postcard photo of Chesapeake and Ohio Railway's M1 No. 500, a coal-fired steam turbine locomotive. Click to enlarge.

(EKE, Public domain, via Wikimedia Commons)



Type and origin

Power type: Steam turbine electric
Builder: Baldwin Locomotive Works
Serial number: 73079–73081
Model: M-1
Build date: 1947–1948
Total produced: 3
​• Whyte 4-8-0-4-8-4 TE
• AAR 2-C1+2-C1-B
• UIC (2'Co1)'(2'Co1Bo')'
Gauge: 4 ft 8+1⁄2 in (1,435 mm)
Driver diameter: 40 in (1,016 mm)
Length: 154 ft 3⁄4 in (46.96 m)
Locomotive weight: 857,000 lb (388.7 tonnes)
Total weight: 617 tonnes (607.3 long tons; 680.1 short tons)
Fuel type: Coal
Fuel capacity: 29.25 short tons (26.54 t)
Water capacity: 25,000 US gallons (95,000 l; 21,000 imp gal)
Boiler pressure: 310 psi (2.14 MPa)
Performance figures
Maximum speed: 100 miles per hour (160 km/h)
Power output: 6,000 hp (4,470 kW) (turbine)
4,960 hp (3,700 kW) (generators)
Operators: Chesapeake and Ohio Railway
Numbers: 500–502
Nicknames: "Sacred Cow"
First run: 1947
Last run: 1949
Disposition: Scrapped 1950