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The "S-13": An MLW-Only Switcher Model

Published: August 19, 2024

By: Adam Burns

The S-13 was a Montreal Locomotive Works (MLW)-only switcher cataloged between 1958 and 1967. A distinguished member of the Alco S-series, which was adapted for the Canadian market, the S-13 was designed primarily for switching and light road service.

Under its robust exterior, the S-13 was the first to utlize a 251C prime mover, capable of generating 1,000 horsepower. This output, coupled with its B-B trucks, made the S-13 a versatile workhorse ideal for the rigorous demands of yard duties.

Throughout its production run, MLW built a total of 56 units, many of which were purchased by Canadian National. The S-13 is remembered for its role in transitioning the rail industry from steam to diesel power, serving as a testament to mid-20th-century locomotive engineering and MLW's contribution to the first-generation era.

Canadian National S-13 #8512 switches the coach yards at Spadina Street on Toronto on September 1, 1984. Doug Kroll photo.

In 1959, MLW introduced the S-13 model, a switcher that marked a pivotal shift from the 539 engine to the more advanced six-cylinder inline 251C power plant.

The S-series had been one of Alco's most successful; in the U.S. the company sold some 3,177 examples within seven cataloged models (S-1 through S-6, and the T-6 transfer variant) according to John Kirkland's book, "The Diesel Builder's Volume Two: American Locomotive Company and Montreal Locomotive Works."

In addition, MLW saw 468 sales which included the S-2, S-3, S-4, S-7, S-10, S-11, S-12, and S-13.  The latter was Montreal's only variant to feature the 251 engine.

This upgrade provided the S-13 with a robust 1,000 horsepower, ideal for more demanding tasks and railroads generally favored switchers with greater power.

Retaining the carbody and trucks of its predecessor, the S-12, the S-13 offered two locomotive weights and two types of electric transmissions, each identified by specific configuration numbers.

The DL-411 units, weighing approximately 233,000 pounds, featured a sophisticated electric transmission system composed of a GT740 generator and four GE731 traction motors with 75:16 gearing.

Meanwhile, the DL-411A variant, heavier at 246,000 pounds, utilized the same generator but replaced the traction motors with more powerful GE752 models and 74:18 gearing, optimizing it for heavy-duty switching, particularly hump yard operations. Both configurations could be equipped with multiple-unit (MU) control and specialized hump control options.

The inaugural S-13 units, built to the DL-411 specification, comprised a trio of locomotives for the Pacific Great Eastern Railway, numbered 1001-1003 and completed in January 1959.

Soon after, the Canadian National placed orders for 23 DL-411 units and 26 DL-411A units, delivered between February and December 1959. This extensive order saw CN’s locomotives numbered 8500-8522 and 8600-8625, respectively, with several equipped for transition control and hump yard operations.

Specifications

Production Roster

1. Specification 411 Modified: Equipped with traction motor transition.
2. Specification 411: Featured GE 731 traction motors.
3. Specification 411A: Featured GE 732 traction motors.

* Was instead built on serial/construction number M3435-01 before the locomotive was completed.

BC Rail S-13 #1001 (ex-Pacific Great Eastern) is seen here at the North Vancouver Yard on May 25, 1984. Doug Kroll photo.

Production continued sporadically over the next few years, eventually culminating in a total of 56 S-13 units: 29 built to the DL-411 specifications and 27 to the DL-411A. These versatile and powerful switchers demonstrate MLW’s commitment to innovation and the railroad industry's transition to more efficient diesel-electric locomotives.