The EMD AB6 were specifically built for the Chicago, Rock Island, and Pacific Railroad. Only 2 were built; numbers 750 and 751. They featured a single 1000hp EMD 12V567 diesel engine. Another engine was added later.
They lasted for 30 years, and both were scrapped.
Built specifically for the Rocky Mountain Rocket, this locomotive was an EMD E6 equipped with a cab and a working pilot. The trains they worked on travelled as a unified train from Chicago to Colorado, but would later divide into two. The CRI&P wanted a locomotive that could look like an integral part of the train when combined, as well as being able to move under its own power. Because it only had to haul 3 cars under its own power, the AB6 only had 1 EMD 567 engine when delivered. The space for the second engine was initially a baggage compartment.
The baggage compartment was replaced by a second engine when trainloads increased. Later on the units were modified for Head-End Power, and were re-assigned to comuter service in Chicago. Both were retired by 1974, none were preserved.
- The AB6 is of a boxcab design.