GENERAL MOTORS - ELECTRO MOTIVE DIVISION -
MODEL E7A & E7B
Passenger Diesel
Electric Locomotives
Production of
passenger locomotives was not allowed during World War Two and the Electro
Motive Division
of General Motors was restricted to the construction of freight locomotives, as
it was felt that this type of power
was more important to the war effort. As the war ended, however, railroads
started planning for the future and
for most lines this included new streamlined trains and the locomotives to pull
them. Prior to the war, EMD had
built a number of passenger locomotive designs, all similar in appearance with
a distinctive slant nose, 1800-
2000HP and riding on trucks with an A1A-A1A wheel arrangement. Each
locomotive, either cab or booster,
contained two diesel engines driving a generator which was used to supply power
to the traction motors, and
steam generators to provide the train with steam for heating or cooling.
As wartime
restrictions eased, EMD started building passenger locomotives again, and in
February 1945 the
first new Model E7A and E7B locomotives were released from the firm's shops at
Lagrange, Illinois (near
Chicago). In most respects the E7 models resembled the pre-war E6 model,
although the A units were
constructed with a shorter nose like the ones used on freight units. A
total of 428 E7A units and 82 E7B units
were constructed by EMD from 1945 to 1949 when the model was discontinued in
favor of the E8.
The E7 was equipped
with two 12-cylinder 567A engines, which were the same as that used on the
contemporary NW2 1000HP switcher. Although very reliable, the use of dual
engines provided a safety factor
over contemporary rivals, such as the ALCO PA, which had only one engine.
Most railroads owned at least
a few E7's, although those with heavy grades and curves ordered high-geared
F-units instead. The Santa Fe,
Western Pacific and Rio Grande never owned one, while the Pennsylvania and New
York Central owned
fleets of them. The E7 was EMD's best selling passenger locomotive.
The model was changed slightly over the
production life of the locomotive with such additions as larger number boards and
changes in side panels.
As the need for
passenger locomotives declined, many roads traded in E7's on second generation
power.
However, many locomotives of this model remained in service until May 1, 1971
when most long distance
passenger service was taken over by Amtrak. A surplus of more modern
locomotives allowed Amtrak to
replace older passenger locomotives (including the E7's) shortly after that
company was formed. By the
mid-1970's most E7 units had been retired and scrapped.
The E7 was in many
ways a conventional locomotive based on tradition and engineering of an earlier
time.
Regardless, sales of this locomotive were very respectable and their use spanned
much of the most turbulent times of American railroads. Their retirement
was based more on the decline of traffic for which they were
built rather than age, and they remain to many people a symbol of the high point
in railroading.
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