EMC AB6

The EMC AB6 was a diesel locomotive type built only for the Chicago, Rock Island and Pacific Railroad by General Motors' Electro-Motive Corporation and delivered in June 1940. Two were built, numbered 750 and 751, for the Rocky Mountain Rocket, a train that ran as one unit from Chicago to Limon, Colorado, then split for Colorado Springs and Denver. The railroad wanted a unit that blended into the streamlined train on the long leg but could run alone with three cars on the branch. EMC therefore built a flat-fronted locomotive based on an E6 booster but with a cab, headlight and pilot. Because the trains it hauled alone were light, each unit first had one 1,000 horsepower EMC 567 V12 engine and a baggage compartment where the second engine would go; the compartment later gave way to a second engine. In 1965 they were converted to head-end power for Chicago suburban push-pull service and were scrapped after the mid-1970s.