Pennsy Electric Locomotives

Class B	C (0-6-0)
B1		Electric switchers have always been rare, because the high cost of an electric locomotive seems wasted on such service, but the PRR built 28 for service primarily in the New York and Philadelphia terminal districts, where they primarily served to switch passenger equipment. Famously noisy, they survived longest in the PRR's Sunnyside Coach Yards in New York, where five lasted into Penn Central years.
Class O	2-B-2 (4-4-4)
O1		Intended as an 'electric E6', eight prototype O1 locomotives were built, with varying electrical equipment, motors, and gear ratios. Apart from early testing, the O1s always ran in pairs; each pair was a different subclass. Electrically and mechanically they were successful, but they were too small and light for their intended service. Paired up they were fine, but then why not build larger locomotives that didn't need pairing?
Class P	2-C-2 (4-6-4)
P5a		In keeping with the PRR's thinking of electric classes as direct replacements for steam classes, the P5a was thought of as an 'electric K4s', a dual-ended Pacific. Just like the K4s Pacifics it replaced, however, the P5a was soon too small for longer, heavier trains; the larger GG1 replaced it there. The L6 having been found lacking in freight work, the PRR put most P5a electrics into the freight pool, regearing them for this work. Mostly, they worked in pairs.
P5a (Modified)		Concerns for crew safety in the boxcab electrics grew after a P5a hit an truckload of apples at a grade crossing, killing the crew. Center 'steeple' cabs were much safer, and 28 new P5a 'modified' locomotives were built in this design, somewhat inspired by the GG1. Often, a streamlined locomotive would be paired with an unstreamlined locomotive, so that the crew would have protection in one direction at least.
P5b		The P5b was an experiment, involving placing traction motors on the guiding axles also, so that every axle was driven. This gave it 5,310 hp instead of a standard P5a's 3,750 hp. However, this proved better in theory than practice; cooling of the truck traction motors was not very effective, and the unit did not produce quite the improvement in hauling ability hoped for. No others were converted.
Class GG	2C+C2 (4-6-6-4)
GG1 (Green, 5 Stripe)		Arguably one of the most famous locomotives ever built, the GG1 had a service life of fifty years, from the 1930s to the 1980s. Enormously powerful and capable, the GG1 was the lasting legacy of excellence the PRR left behind. This shows a GG1 in the original livery; DGLE with five gold pinstripes, as designed for them by the industrial designer Raymond Loewy.
GG1 (Green, 1 Stripe)		The later PRR livery, simplified with a single stripe (no longer gold leaf, but Dulux Gold paint, a buff color), large 'PENNSYLVANIA' lettering and a large, drop-shadowed Keystone herald. Most locomotives bore this livery until the end of the PRR in 1968; some bore it until their retirement in the 1980s, with only the railroad names painted over.
GG1 (Tuscan, 5 Stripe)		Ten locomotives were painted in Tuscan Red for special trains (the Broadway Limited, among others). This scheme was later adopted for all passenger diesels, but no other GG1s received it.
GG1 (Tuscan, 1 Stripe)		Two units were painted in a single stripe version of Tuscan red with large lettering and Keystone herald.
GG1 (Silver, 1 Stripe)		Three GG1s were painted in this scheme of silver with a red band, for service with the Congressional Limited, whose cars also followed this color scheme.