Northern Pacific 4025, a class Z-3, on the Milwaukee mainline bridge over the Clark Fork River at Saint Regis, Montana, on May 28, 1952. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive, truss bridge.

Northern Pacific 4025, a class Z-3, leads an eastbound extra freight on the Milwaukee mainline between Haugan and Saint Regis, Montana, on May 28, 1952. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive, freight train, river.

Northern Pacific 4025, a class Z-3, leads an eastbound extra freight across a short bridge on the Milwaukee mainline between Haugan and Saint Regis, Montana, on May 28, 1952. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive, freight train, plate girder bridge.

Northern Pacific 4025, a class Z-3, approaches Saint Regis, Montana, with an eastbound extra freight on the Milwaukee mainline on May 28, 1952. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive, freight train.

Northern Pacific 1719, a class W-3, approaches Saint Regis, Montana, with a westbound extra local freight on May 28, 1953. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive, freight train, river.

Northern Pacific 5409, an Electo-Motive Division FT, rounds the curve east of Saint Regis, Montana, with a westbound extra freight on May 28, 1953. Photo by J.M. Fredrickson. Other Subject Classes: diesel locomotive, freight train, river.