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locomotive to not only replace the rest of its outdated GG1s but also retire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.
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.
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.