Union Pacific applies PTC to 'Big Boy' steam locomotive

Union Pacific Railroad has equipped one of its legendary steam locomotives, the "Big Boy" No. 4014, with positive train control (PTC).

In January, a new design approach emerged to enable UP to achieve its goal of equipping the 80-year-old locomotive with PTC, one of the industry’s newest technologies. PTC is designed to automatically stop a train before an accident occurs.

When UP officials in 2016 began discussing the idea of applying PTC to the unit, there wasn’t a clear, feasible technical path to achieve it, said Greg Richardson, UP’s general director of operating technologies-engineering, in a post on the railroad’s InsideTrack report.

The new design approach is based on the PTC onboard computer of a trailing diesel locomotive. Solutions were engineered to address placement and powering of the PTC display unit in Big Boy’s cab; communications between the PTC display unit and PTC computer in the trailing locomotive; and interconnection of the brake systems on the 4014 and the trailing locomotive, UP officials said.

The solution is also planned for UP’s steam locomotive No. 844, they said.

To learn more about UP's Big Boy locomotive PTC project, click here.