The Pennsylvania Railroad GG1: The New Haven EP3a

The New York, New Haven & Hartford Railroad needed electric passenger locomotives for its 11,000 Volt, 25 cycle (HZ) electrified railroad and ordered ten new locomotives from the General Electric Company in 1930.

GE had designed and built a very successful electric locomotive in 1929 with a 2-C+C-2 wheel arrangement for the Cleveland Union Terminal Co. They used this same wheel arrangement and combined it with twin geared quill drives which was favored by the NYNH&H.

In the GE design, each of the six driving axles was surrounded by a rotating quill (a hollow tube) that was connected to two large gears that wear almost the same size as the drivers. Each of the traction motors were double-ended having a shaft and pinion on each end. For each axle two motors were bolted together and attached to a bearing assembly which allowed the motors to ride on the quill and the pinions to mesh with gears. Mounting the motors on the quill allowed the driving wheels and axle to move in reaction to track conditions without affecting the meshing of the pinions and gears. The traction motors turned the gears that reached into and turned the driving wheels through a spider and spring cup connection.

The ten box cab locomotives were built in GE's Erie, PA plant and were delivered in 1931. They were designated as Class EP3a and assigned road numbers 0350 through 0359. At the time of delivery, the NYNH&H had an established tradition of numbering its electric locomotives with an "0" prefix, which meant it was "other than steam". These locomotives weighed 404,000 pounds had twelve traction motors with a combined HP rating of 3440 HP, exerted 68,500 pounds of tractive effort and were capable of speeds reaching 80 mph.

It was one of these handsome locomotives, number 0354, that was loaned to the PRR for testing at a special test track that was built in Claymont, DE. The New Haven EP3a was tested against the P5a and it showed far better acceleration and tracking characteristics. The excellent test results of the 2-C+C-2 locomotive led to the development of the GG1.

All of the EP3a were taken out of service in 1955.

Specifications for Class EP3a
Wheel Arrangement:2-C+C-2 (4-6-6-4)
Length:77' - 0"
Drivers:62" dia.
Weight on Drivers:272,000 lbs
Total Locomotive Weight:404,000 lbs
Line Voltage:11,000 Volts, 25 cycle (HZ) AC
Traction Motors:12 @ 286.6 HP, single phase
Tractive Effort:68,500



Much thanks to Richard Duley who has helped to provide a great deal of the information found on this page.