137-2015 GG1 Conrail Bicentennial 4800The GG1, one of the PRRs most famous and recognizable locomotives, is also one of the most curiously designed. Technically two locomotives under one shell (a G class locomotive is a 4 6 0 by PRR specification, therefore the GG1 was two G locomotives in a 4 6 0: 0 6 4 arrangement). This added up to a 4. 6k horsepower locomotive that was staggeringly powerful, even by todays standards. Designed in the 20s, built in 30s, and not retired until the 80s,