By Eric Berger

ALBUQUERQUE, N.M. — The odds that newly-rebuilt Santa Fe 2926 might someday operate again on Class I rails dropped into the realm of real possibility when a Positive Train Control system designed to allow steam engines to operate in the modern era was installed on the big Baldwin 4-8-4 and successfully tested on December 8.

The achievement caps a four-year development effort and the road-testing of a prototype aboard Union Pacific “Big Boy” 4014 during its 3,400-mile tour last summer, the first such use of a PTC system on a steam locomotive. Known as LeaPTC, the system utilizes computers and equipment in a trailing diesel that is linked to a terminal in the steam cab. As with the PTC application in diesels, the terminal displays a route map that is continuously updated with speed restrictions, signal indications, work zone locations and other information, while another installation enables the engineer to control accompanying diesels. In an emergency, LeaPTC can activate the train brakes on the steam locomotive.

This approach eliminates the need to equip a locomotive with a complete PTC system and antennas, dramatically reducing the cost of complying with the Federal Railroad Administration’s PTC mandate. The system also has potential applications for push-pull commuter trains utilizing an engine on one end and a control cab on the other. Partial funding for the system came in 2019 through a $25,000 grant from the John H. Emery Rail Heritage Trust. The foundation provided similar grants that year toward the installation of PTC on Milwaukee Road 261 and Nickel Plate Road 765. 

The massive Northern-class Baldwin moved under its own power in July for the first time since 1954, culminating in a two-decade restoration project by the New Mexico Steam Locomotive and Railroad Historical Society. Noteworthy contributions to making the system work with a trailing diesel go to NMSLRHS member John Howard, who is also involved with work on another Santa Fe 4-8-4, ATSF 3751 in San Bernadino.