Link Pins

The Driving Spring Link Pins played a fascinating role in the history of the PRR T1. To some degree the T1’s “slippery” reputation may stem from the fact that in the two prototype T1 locomotives the front and rear engines were linked together by the spring rigging. During prototype testing it was determined that the front engine tended to lift off the rail in curves with this arrangement. As a result the PRR modified the two prototypes to separate the suspension for the front and rear engines. The front engine was equalized with the leading truck and the rear engine was equalized with the trailing truck. The original PRR drawing (E431144) bears the result of this modification in that the total number of Driving Spring Link Pins on the prototypes was reduced with two black lines of pencil from 10 to 8. This modification was carried forward on all 50 production units, and with that you might say the PRR solved the slipping problem.

Andy Pullen, one of the Trust’s finest machinists, is producing the eight Driving Spring Link Pins for 5550. Andy is working from original PRR mechanical drawings extracted by The T1 Trust from the Pennsylvania State Archives. Andy is no stranger to steam locomotives and his more than thirty years of experience as a machinist includes two years spent working for the Norfolk Southern Steam Program. Andy currently serves as a machinist for the US Naval Academy in the Division of Engineering and Weapons.