C&S was also the parent company of the Fort Worth and Denver Railway, which ran from a connection at Texline south and east into Texas.

The FW&D was established as a separate company because Texas law required that railroads operating within its borders must be incorporated within that state.

The Colorado and Southern narrow gauge operations never owned a new engine, all the motive power was inherited from the former companies.

In May 1941 the last of the Clear Creek lines began being torn up between Golden, Colorado and Idaho Springs.

The dual-gauge third rail that had allowed narrow-gauge trains to run between Denver and Golden was also removed.

The last narrow-gauge operation, between Leadville and the Climax mines, was converted to standard gauge to handle heavy traffic from World War II.

The last Colorado and Southern narrow-gauge train, pulled by engine 76, ran the 28 mile roundtrip on August 25, 1943.

Some are on display in Colorado, one mail car found its way to Nebraska, and some boxcars are on the White Pass and Yukon Route in Alaska.

The Georgetown Loop was rebuilt as a tourist railroad in the 1980s and can be ridden from April through the first week in January.