EMD AB6
Encyclopedia
The EMC AB6 was a type of diesel locomotive
built exclusively for the Chicago, Rock Island and Pacific Railroad
(the "Rock Island Line") by General Motors' Electro-Motive Corporation and delivered in June 1940. Two examples were built, numbered #750 and #751. They were built for the Rocky Mountain Rocket
passenger train, which travelled as a unified train from Chicago, Illinois, to Limon, Colorado
, but then divided; with one segment going to Colorado Springs, Colorado
, and the other to Denver, Colorado
. The Rock Island desired a locomotive that could look like an integrated part of the train during the Chicago-Limon portion of the route, but could then be operated independently to take three cars to Colorado Springs. A regular, cab-equipped A-unit could have been purchased, but that would have ruined the streamlined look of the train, so the RI had EMC build a flat-fronted locomotive based on an E-series
E6B (B unit
) but with an operating cab, headlight, pilot
, and other features to enable it to operate as an independent locomotive.
Since the small three- and four-car trains the units would have to haul independently were very light, the AB6 pair were built with only one 1,000 hp EMC 567 V12 engine
, and a baggage compartment where the second engine would have been. Later, with increasing trainloads, the baggage compartment was replaced with a second engine.
In 1965, the units had their steam generator
s replaced with head-end power and were reassigned to push-pull
suburban service in the Chicago area. In this form, they lasted until the mid 1970s.
Diesel locomotive
A diesel locomotive is a type of railroad locomotive in which the prime mover is a diesel engine, a reciprocating engine operating on the Diesel cycle as invented by Dr. Rudolf Diesel...
built exclusively for the Chicago, Rock Island and Pacific Railroad
Chicago, Rock Island and Pacific Railroad
The Chicago, Rock Island and Pacific Railroad was a Class I railroad in the United States. It was also known as the Rock Island Line, or, in its final years, The Rock.-Incorporation:...
(the "Rock Island Line") by General Motors' Electro-Motive Corporation and delivered in June 1940. Two examples were built, numbered #750 and #751. They were built for the Rocky Mountain Rocket
Rocky Mountain Rocket
The Rocky Mountain Rocket was a streamlined passenger train of the Chicago, Rock Island and Pacific Railroad. Rock Island's train numbers 7 and 8 ran from Chicago's LaSalle Street Station to Denver's Union Station and Colorado Springs, Colorado...
passenger train, which travelled as a unified train from Chicago, Illinois, to Limon, Colorado
Limon, Colorado
Limon is a Statutory Town that is the most populous town in Lincoln County, Colorado, United States immediately east of Elbert County. The population was 2,071 at the 2000 census. Limon has been called the "Hub City" of Eastern Colorado because Interstate 70, U.S. Highways 24, 40, and 287, and...
, but then divided; with one segment going to Colorado Springs, Colorado
Colorado Springs, Colorado
Colorado Springs is a Home Rule Municipality that is the county seat and most populous city of El Paso County, Colorado, United States. Colorado Springs is located in South-Central Colorado, in the southern portion of the state. It is situated on Fountain Creek and is located south of the Colorado...
, and the other to Denver, Colorado
Denver, Colorado
The City and County of Denver is the capital and the most populous city of the U.S. state of Colorado. Denver is a consolidated city-county, located in the South Platte River Valley on the western edge of the High Plains just east of the Front Range of the Rocky Mountains...
. The Rock Island desired a locomotive that could look like an integrated part of the train during the Chicago-Limon portion of the route, but could then be operated independently to take three cars to Colorado Springs. A regular, cab-equipped A-unit could have been purchased, but that would have ruined the streamlined look of the train, so the RI had EMC build a flat-fronted locomotive based on an E-series
EMD E-unit
EMD E-units were a line of passenger train diesel locomotives built by the General Motors Electro-Motive Division and its predecessor the Electro-Motive Corporation . Final assembly for all E-units was in La Grange, Illinois. Production ran from May, 1937, to December, 1963. The name E-units...
E6B (B unit
B unit
A "B" unit, in railroad terminology, is a locomotive unit which does not have a driving cab, or crew compartment, and must therefore be controlled from another, coupled locomotive with a driving cab . The term booster unit is also used. The concept was largely confined to North America...
) but with an operating cab, headlight, pilot
Pilot (locomotive)
In railroading, the pilot is the device mounted at the front of a locomotive to deflect obstacles from the track that might otherwise derail the train. In some countries it is also called cowcatcher or cattle catcher....
, and other features to enable it to operate as an independent locomotive.
Since the small three- and four-car trains the units would have to haul independently were very light, the AB6 pair were built with only one 1,000 hp EMC 567 V12 engine
V12 engine
A V12 engine is a V engine with 12 cylinders mounted on the crankcase in two banks of six cylinders, usually but not always at a 60° angle to each other, with all 12 pistons driving a common crankshaft....
, and a baggage compartment where the second engine would have been. Later, with increasing trainloads, the baggage compartment was replaced with a second engine.
In 1965, the units had their steam generator
Steam generator (railroad)
Steam generator is the term used to describe a type of boiler used to produce steam for climate control and potable water heating in railroad passenger cars...
s replaced with head-end power and were reassigned to push-pull
Push-pull train
Push–pull is a mode of operation for locomotive-hauled trains allowing them to be driven from either end.A push–pull train has a locomotive at one end of the train, connected via some form of remote control, such as multiple-unit train control, to a vehicle equipped with a control cab at the other...
suburban service in the Chicago area. In this form, they lasted until the mid 1970s.