Like all others, this GG1 was designed and geared for passenger service and possibly pulled the heavyweight CONGRESSIONAL on occasion. Once the Congressional was equipped with lightweight cars in 1952 I would speculate the 4800 never pulled that train. The 1952 train generally was pulled by Tuscan GG1's painted specifically for the Congressional and Senator trains.
At some point ca mid'50's - early '60's the 4800 had its steam boiler removed and was re-geared for freight service. A friend of mine who was an Amtrak / Conrail engineman said the 4800 was about the smoothest and quietest of all the GG1's. He only ran the 4800 in freight service since he didn't hire on until about 1970 when the loco was no longer equipped for passenger service.