Driving a T1 separated the men from the boys. A perfectly tuned T1 in the hands of a skillful engineer was a racing thoroughbred, capable of cruising at 100 mph with a 16-car limited. But a less well-maintained T1 driven by an average engineer could be a slippery, unforgiving beast - and that was more often the case in the waning days of steam on the Standard Railroad of the World.
Although it looked at first glance like an articulated, the T1 was in fact a duplex. It was an attempt to improve on the 4-8-4, the reigning queen of fast steam passenger power, by splitting the drive mechanism in two but retaining the 4-8-4's rigid frame. The concept originated in the early 1940s with Baldwin Locomotive Works' Chief Engineer Ralph Johnson.
The duplex addressed one of the key drawbacks of steam: the massive weight of reciprocating rods and other machinery that produced a pounding on the rails and limited engine speeds. By doubling the number of cylinders, a duplex design could have shorter, lighter rods, smaller pistons, lower piston speeds, and produce less wear and tear on both the engine and the track. On paper, Baldwin's T1 design looked like the long-awaited replacement for the Pennsylvania Railroad's aging fleet of K4s Pacifics. And a striking Raymond Loewy-designed exterior promised a great public relations image. The Pennsy's one change to Baldwin's original design was its insistence on the novel Franklin poppet valve gear, based on previous successful tests with a K4s.
In initial trials, the pair of prototype T1s built in 1942 looked like winners. Nos. 6110 and 6111, the prototypes for our Premier models, delivered over 6000 horsepower, exceeding the PRR's design requirements. A T1 could out-pull a four-unit Electro-Motive FT diesel at all speeds above 26 mph. Based on the test results, the Pennsy ordered 50 more T1s, built by Baldwin and the road's own Altoona shops in 1945-46.
Outside of the test arena, however, the production T1s proved problematic. With all but the best engineers, a T1 was prone to violent slipping by one pair of drivers, as weight shifted between the two driver sets. While this was disconcerting when starting a train, it was absolutely frightening when it occurred at speed. Furthermore, the drive mechanisms for the poppet valve gear were located in nearly inaccessible spots, resulting in poor maintenance that hurt engine performance.
But perhaps most important, the T1 simply arrived on the scene too late. By the late 1940s, the diesel revolution was on, and there was not time to address the T1s problems. After serving several years on crack passenger runs between Harrisburg and Chicago, the T1s were demoted to lesser trains and eventually retired and scrapped in the early 1950s. Alvin Stauffer, late poet laureate of Pennsy commentators, put it best: "The T1 was everything: beautiful, unusual, fast, slippery, success and failure. Pennsy's chunk of 'too much experimentation' was born too late and died too soon."