A somewhat foamish response, but the transformers for the GG1s (the other large hurdle towards restoration) are strikingly similar to those of the AEM-7. I know of about a dozen of those to still exist; I’m sure Amtrak could part with one or two to be used for parts.

I think historically, a lot of the argument against a “GG2” is that it’s not a true restoration, and would utterly destroy the historic fabric of any locomotive that had this surgery performed. A question we must ask ourselves is: is sacrificing one of the 13 remaining units worth it to see Lowey’s streamlined styling roll on the high iron again?

Well, aren't they in fact building a "T2"?

Sure.

As long as you also find a patron to build you a stand-alone electrified railroad to run it upon.

And sorry, the Black Mesa & Lake Powell Railroad is no longer a viable option. How about the Deseret Power RR in Colorado/Utah?

How about a double header with the T2 and the GG2 on the FRA test track in Colorado?

The "T2" would be what was under the heading of "5551" on the T1 Trust's engineering discussions: the duplex with all the design compromises and operating issues worked out. It would not resemble a historic T1 in a great many respects, and therefore doesn't satisfy the Trust's original perceived mission of re-creating a historic locomotive with as few as possible changes (the principal one being the adoption of 'Franklin type D' drive-arm rotary-cam poppet valve gear). We could have quite a fun discussion about the details of such a thing, but it sure ain't preservation.

The only "real" change needed to make a GG1 operable is replacement of the Pyranol transformers with some reasonable substitute, leaving the 'rest' of the historic drivetrain fabric including the universal motors inherited from the New Haven prototype intact. I see no particular need to replicate the multiple-tap control system when doing this. Note that this is NOT the approach that puts two AC-motor armatures in a frame that will mount in place of a prototype twin motor, leaving the historic fabric of the underframe and drive essentially intact.

A "GG2" would have followed the design of the DD2, with the larger 428A motors and associated drive wheels -- this is the locomotive laid out in the 1943 electrification proposal, reading between the lines. I doubt there would be too many fans -- PRR ot otherwise -- who would much care for that aesthetic, let alone pay to ride behind one. No matter how you modernize this type of locomotive, you'll still have a 230+-ton boat anchor of a locomotive with restricted braking capability and, unless you arrange one-piece quill-drive-compatible wheels... issues with keeping tires properly seated.