For its passenger service, the Denver & Rio Grande Western Railroad purchased 4- 8-4s in two orders, from the Baldwin Locomotive Works. In 1929, 14 Class M-64 locomotives and in 1938, another five, this time Class M-68. The D&RGW liked the name "Western" instead of "Northern" for these locomotives.

The Rio Grande ran fascinating combinations of heavyweight and streamlined cars in their trains from 1948 to 1968. Most heavyweight cars were painted from the old Pullman Green into the "Grande Gold" color scheme in the early 50s. This colorful period began with "Westerns" hauling the heavyweight EXPOSITION FLYER with brand-new Budd CALIFORNIA ZEPHYR cars (especially Vista- Dome coaches) mixed in. This is one of the few instances where one could ride a regularly-scheduled dome car behind a steam loco.

By 1956, all of the D&RGW "Westerns" had been sent to the scrapper. The "Westerns" gave way to FTs, Alco PAs, F3s and eventually the F7s. Once the CZ consists were complete, Rio's heavyweights were eventually repainted and used in the ROYAL GORGE, YAMPA VALLEY MAIL and PROSPECTOR. For the ZEPHYR, the PAs were painted solid silver with orange noses. The FTs, F3s and PAs were originally delivered and run in a black body/gold stripe scheme till the early 50s then all were repainted "Grande Gold". The PROSPECTOR and ROYAL GORGE were well-known for their combo consists till their demise in the mid-60s. The Rio Grande also purchased streamlined coaches, diners, dome-observation cars and RPOs from the Chesapeake and Ohio in the early 50s.