PRR GG1 An American Classic

PRR GG1

An American Classic

GG1 An American Classic

Amtrak electrics

The Pennsylvania Railroad’s GG1 class of electric locomotives was built between 1934 to 1943 at the PRR shops in Altoona, Pennsylvania, with a total of 139 units constructed. They remained in service with the PRR’s successors until the early 1980s. The GG1 became one of the most recognized and famous classes of locomotive worldwide.

Technical information

The GG1s were large locomotives, 79 feet 6 inches (24.2 m) long and weighing 477,000 pounds (216,000 kg). The double-ended main body was a single unit formed as a bridge-truss framework and clad in welded steel plate. The cabs were set up high about a third of the way along the locomotive from each end for greater crew safety in the event of a collision. A narrower section of nose in front of the cab windows was lowered to improve the view forward, although the central part of the nose remained full height to carry the current-collection pantographs. The bodywork as a whole was smoothly rounded, with an appearance that suggested immense power and speed.

This was mounted upon two great cast steel locomotive frames linked by a hinge at the locomotive’s middle which allowed side-to-side movement. Six driving wheels(three axles) were fitted towards the center of the locomotive on each truck (twelve in total) and a four-wheeled, unpowered guiding truck was mounted toward each end. In the Whyte notation for steam locomotives, each frame comprised a 4-6-0locomotive; in the PRR’s classification system, 4-6-0s were class “G”. The GG1 consisted of two such locomotive frames mounted back to back, so it was classified GG—4-6-0+0-6-4. This arrangement is called 2-C+C-2 in AAR wheel arrangement notation. Each driven axle was powered by two 385 hp (305 kW) GEA-627-A1 traction motors mounted above and to either side of the axle. Drive was through a reduction gear and a quill drive assembly.

While the famous industrial designer Raymond Loewy did not design the shape of the GG1 electric locomotives (borrowed from the earlier P5a), he did improve their looks by recommending the use of a smooth, welded construction instead of riveted assembly, along with a pinstriped paint scheme to highlight their smoothly rounded forms; the “streamline” style, evoking speedy travel, was popular at the time. The mechanical design behind the GG1 came from the New Haven Railroad EP3 electric. The New Haven allowed the PRR to borrow a pair of EP3s for testing, and the PRR was quite impressed with their performance and decided to base the design of its electric locomotive on the EP3′.

The GG1 was designed to run on the standard Pennsylvania Railroad catenary power of 11,000 V AC, 25 Hz. This high voltage was stepped down by a large transformer mounted in the center of the locomotive body for the traction motors, cooling blowers and all other onboard equipment. The locomotive’s power was controlled via a tap-switching arrangement; the number of secondary windingsin use could be varied, thus adjusting the output voltage. The units were rated at 4,620 hp (385 hp per motor) continuous rating and a maximum of 9,500 hp at 49 mph (intermittent duty). For passenger service, the GG1 was geared to run at 100 mph maximum, although it achieved 110 mph in testing. For freight service, the locomotive was geared to run at 90 mph maximum.