Gulf, Mobile & Ohio No. 1900, the sole Ingalls S-4.

(Photo by John Stephen Foster, Fair Use via


Ingalls logo.


The Ingalls 4-S was an experimental American locomotive built by Ingalls Shipbuilding immediately after World War II. Intended as the first of many Ingalls-built locomotives, it was the only one the company built. It served on the Gulf, Mobile and Ohio Railroad (GM&O) until it was retired in 1966; it was scrapped the following year.


The Ingalls S-4 front left view.

(The National Supply Company, W. Lenheim Collection)


Ingalls Shipbuilding

Ingalls Shipbuilding is a shipyard located in Pascagoula, Mississippi, United States, originally established in 1938, and now part of HII. It is a leading producer of ships for the United States Navy, and at 12,500 employees, the second-largest private employer in Mississippi.


Design and development

At the end of World War II, Ingalls Shipbuilding developed plans for a line of diesel-electric locomotives to serve the expected post-war market. Five models were projected; the first, and as it proved only, to be built was a prototype of the largest, the model 4-S.

A single demonstrator was planned in December 1945, and built in March 1946, numbered No. 1500. The design of the locomotive was considered advanced, including a "turret cab" arrangement, which improved the crew's vision. The prime mover selected for the locomotive was the inline-8 65LX8, based on a marine diesel engine built by Superior Engines & Compressors; and modified for railroad use by Cooper-Bessemer, with Elliott Company providing the turbocharger. The 4-S produced 1,650 hp (1,230 kW), of which 1,510 hp (1,130 kW) was available for the production of tractive effort by the locomotive's electric drive, but marketed as 1,500 horsepower. Provision was made for the installation of a steam generator for passenger service. The locomotive was equipped with connections for multiple unit operation.


Operational service

The 4-S demonstrator was tested by a number of railroads, including the Louisville and Nashville, Seaboard Air Line, Mississippi Export Railroad, Gulf, Mobile and Ohio, and the Southern Railway; however no orders materialized for the type, or for any other of Ingalls' proposed locomotives. The lack of orders combined with issues with the supply of components resulted in Ingalls electing to abandon its plans for locomotive construction; the sole 4-S was the only locomotive they ever built. It was sold to the Gulf, Mobile and Ohio Railroad for US$140,000 in June 1946, where it received the road number 1900.

The 4-S served with the GM&O, operating primarily from Mobile, Alabama, to Jackson, Mississippi, but also served around Meridian and Laurel. It was used in switching duty, earning a reputation for toughness; it once derailed, landing inverted, but was repaired and returned to service in short order. In 1966, the railroad traded it in to EMD as partial payment for new SD40s. It was offered to the Illinois Railway Museum for US$3,000, but the museum was unable to raise the funds. When no other buyers materialized, it was sold to Pielet Brothers in 1967, where it was scrapped.



Type and origin
Power type: Diesel-electric
Builder: Ingalls Shipbuilding
Serial number: 1501
Build date: March 1946
Total produced: 1
Configuration: AAR B-B
Gauge: 4 ft 8+1⁄2 in (1,435 mm)
Length Body: 56 ft 6 in
Width: 10 ft 0 in
Height: 15 ft 0 in
Locomotive weight: 272,000 lb (123.4 tonnes)
Fuel capacity: 1,000 US gal (3,800 l; 830 imp gal)
Lubricant capacity: 150 US gal (570 l; 120 imp gal)
Coolant capacity: 280 US gal (1,100 l; 230 imp gal)
Sandbox capacity: 28 cubic ft
Prime mover: Superior Engines & Compressors 65LX8
Engine RPM: Maximum RPM 660
Aspiration: Turbocharged
Generator: GE GT581
Traction motors: GE 752 (4)
Cylinders: 8
Cylinder size: 12.5 in × 15 in (320 mm × 380 mm)
Gear ratio: 15:63
Performance figures
Maximum speed: 65 mph (105 km/h)
Power output: 1,650 hp (1,230 kW)
Tractive effort:
​• Starting 72,000 lbf (320.27 kN)
• Continuous 42,800 lbf (190.38 kN)
Operators: Gulf, Mobile & Ohio
Road Number: 1900
Retired: 1966
Disposition: Scrapped in 1967


See Also:

Diesel-Electric Locomotives