>Again, not looking at the checkbook, could it be even better to get the innards of a Vectron, and replace the traction motors?

Between the trolley wire and the motor leads, all the electrical equipment has to do is take the available trolley voltage and convert it to something the motors can use, which would be anything between 0 hz and 25 hz and vary between 100 and 380 volts for the original traction motors (if your are going to use only one motor of each pair, it would degrade the locomotive's hp by 50%).

>I am aware of one historic vehicle (an EMU) where the complete traction equipment from a (at the time) current EMU was used.

ORM's Red Bird was motorized with electrical equipment from a North Shore car, no drilling necessary to mount the electrical gear to the car's underbody.

>In another case, they were apparently in talks with Bombardier for a 4-system TRAXX equipment to put into another historic train. However, they eventually decided to do a "soft" renovation, and stayed with the original concepts.

After speaking with someone familiar with MMTB practices, it won't surprise me at all to learn that the cause of the recent trolley fires in Memphis was the result of the rebuilder straying from the "original concepts" (like removing the LB protection from the controllers).

>Back to the GG1, the question is, of course, how high the power rating actually should be; it may not be necessary to recreate the original rating, but somewhat lower could do as well. This could mean that only 4 axles would be driven (which would, in the case of salvaging the equipment of an AEM-7 make things way easier).

There is no reason to go to all the expense and trouble of modifying the quill drives for a different type of motor. Besides, changing the number of powered axles would adversely affect tracking characteristics. I was once told by a knowledgeable person that the PRR experimented with adding traction motors to the pilot trucks but found it ruined the GG1's excellent tracking qualities at track speeds.

All the AEM-7 power supply (or equivalent) would have to do is put out current at anywhere from 0 hz to 25 hz and voltage between about 100 and 380 (motor speed control via frequency changing wouldn't work, BTW). Aside from power for auxiliary circuits (TM blowers, air compressors, control power) the only addition consideration would be to arrange the overload protection(s) of the AEM-7 stuff to protect the weakest link: the [original] traction motors or the AEM-7 power supply.