The AEM-7 Motor
The AEM-7 electric locomotive resulted from a test the passenger carrier did on French and Swedish models.
After several tests Amtrak was pleased with the Swedish Rc4 and would
eventually settle on it as a basis for what would become its AEM-7. The
new electric locomotive model was built by General Motors' Electro-Motive Division (EMD) in the late 1970s through the 1980s and allowed Amtrak to retire
the rest of its GG1 fleet and unsuccessful E60s, which were originally
mean to place its aging fleet of electrics in the mid-1970s. Today,
most of these high-speed motors are still in operation on Amtrak’s
system up and down the Northeast Corridor, after nearly three decades of
continuous operation, a testament to their high quality construction
|Boxy but powerful and reliable, AEM-7 #910 and mate zip by the station at Perryville, Maryland on August 29, 2004.|
the late 1970s Amtrak was looking for a new high-speed electric
locomotive to not only replace the rest of its outdated GG1s but also retire
its E60s, a General Electric product, which turned out to be a big disappointment (a poor design of
its trucks and extremely heavy weight for a passenger locomotive
precluded it from operating at speeds over 90 mph). This setback was somewhat surprising considering that through the years GE had been known as a quite competent designer and builder of electric locomotives. So, after being
pleased with tests done on a Swedish Rc4, the most successful electric
locomotive design at the time, Amtrak contracted with EMD to build a
fleet of 54 passenger electrics dubbed AEM-7s.
These motors used the latest in electric locomotive technology featuring
thyristor motor control and traction motors that provided maximum power
without wheel slip. The Amtrak’s AEM-7 was noticeably more powerful and heavily built than the Swedish models,
partly due to design mandates by the Federal Railroad Administration.
The AEM-7 could easily cruise over 100 mph on the NEC and could deliver a
whopping 7,000 hp with over 53,000 pounds of tractive effort. Today,
the AEM-7 fleet continues to provide daily commuter service duties for
Amtrak, along with the South Eastern Pennsylvania Transportation
Authority (SEPTA) and Maryland Rail Commuter (MARC) which also both own a
small fleet of the motors.
|AEM-7 #952 speeds through Middle River, Maryland on February 10, 2004.|
In one of the few instances in recent memory in which an EMD product was
constructed far superior to a GE design (it should be noted that EMD
did not really design the model itself although the builder collaborated with other manufacturers), the AEM-7 was simply a much better design and more efficient
locomotive than the E60 and its variants. Where the E60 featured a C-C
truck setup (three axles per truck) the AEM-7 used a smaller B-B design
(two axles per truck). This not only allowed the EMD model to be much
smaller at just 51 feet in length (as opposed to the E60's 70 feet) but
also much lighter at just 101 tons. In contrast, the GE's model weighed
nearly twice that amount, 193.5 tons. The lighter weight allowed the
AEM-7 to be much more stable on the rails and operate at higher speeds
of 125 mph.
Amtrak began placing orders for the AEM-7 in 1978, before it
had even completed its order of E60CPs and E60PHs. All of the model's
internal components were designed and built by Allmänna Svenska
Elektriska Aktiebolaget (ASEA) of Sweden. However, the locomotive's
stainless-steel, ribbed carbody may look familiar to some as it was
designed by the legendary Budd Company, which by the late 1970s was
still serving a limited market for passenger equipment.
Amtrak's first batch of AEM-7s, 46 units, began service between
1980 and 1982 after it had received its first a year earlier in 1979.
By 1988 the carrier's order for the model was complete, at 54 units,
more than double the total number it had purchased of GE's E60 design.
Altogether, EMD would construct 65 AEM-7s as both the Southeastern
Pennsylvania Transportation Authority (SEPTA) and Maryland's MARC
commuter service purchased a few examples of the model. Today, Amtrak's
entire fleet of AEM-7s remain in regular service along the Northeast
Corridor, save for those few destroyed in wrecks. In 1999 the units
were rebuilt in conjunction with Alstom which upgraded a number of them
for AC power. As such they have been reclassified as AEM-7DCs and
Please Click Here To Return To The Main Electric Locomotives Section
|AEM-7 #946 speeds over the massive Susquehanna River Bridge near Havre de Grace, Maryland with regional train #126 on May 12, 2006.|
For more reading about Amtrak’s AEM-7 electrics and other electrics consider Electric Locomotives
from Brian Solomon. Not only does the book give a nice overview about
the Amtrak's electrified operations it also covers American electric
locomotive technology in general that includes nearly 100 pages of
excellent photography. Another book that covers modern electric locomotives like the AEM-7 is Locomotives: The Modern Diesel and Electric Reference by author Greg McDonnell. Mr. McDonnell's book is much larger in scope than Solomon's Electric Locomotives, covering newer electrics (and diesels) on nearly 250 pages which are packed full with excellent photography, illustrations,
and diagrams. The book has received superb reviews by readers and is
perhaps the best current work out there covering the topic.