In the early 1980s, Amtrak was still running the then 40+ year old GG1s they had inherited as the main motive power on their electrified lines in the northeast U.S. The E60s intended to replace them could not safely achieve speeds much above 90 mph, and Amtrak wanted to be able to run faster. Their solution to this, what was to become the AEM-7, was based on a Swedish design. It was far lighter than the GG1s or E60s, and could operate safely at much higher speeds. The AEM-7s are still in use today as the primary workhorses along Amtrak's northeast corridor routes.
AEM-7s are a common sight in Philadelphia, where I live, and I even have to ride in trains pulled by them occasionally. Our metro transit system, SEPTA, also owns a few AEM-7s for fast commuter operations.
My main goal in building this model was to create a really fast PF locomotive using XL motors. My AEM-7 features 2 XL motors fixed to the body of the locomotive and geared up 3:1 to the trucks. The speed is further increased by a 5:3 up-gearing within the trucks. I think it would be difficult to coax too much more speed out of these motors, but I am pleased with the performance as-is.