Pennsylvania Railroad

The Pennsylvania Railroad {{reporting mark|PRR}} was an American railroad existing 1846–1968, after which it merged into Penn Central Transportation. Commonly referred to as the Pennsy, the company was headquartered in Philadelphia, Pennsylvania. The company's symbol was a keystone (Pennsylvania's symbol) with the letters PRR overlapping inside it. When colored, it was bright red with silver-grey edges and lettering (although it also appears in metal leaf outline on a wooden background on station benches).

Steam locomotives

For most of its existence, the PRR pursued a motive power policy of conservatism and standardisation. Almost uniquely among American railroads, the Pennsylvania designed most of its steam locomotive classes itself and built a fair proportion of them in its own Altoona Works - in fact, the PRR is believed to have been the 4th greatest builder of steam locomotives in the United States, after the three largest commercial builders.

Related Topics:
Steam locomotive - Altoona

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Outside builders were, of course, used - the sheer numbers of locomotives the PRR ordered were far greater than its own works could produce. Unlike most roads who left the majority of the decision-making and design to the locomotive builder, giving only a broad specification, the PRR generally used a commercial builder as a subcontractor, building exact replicas of an existing PRR design.

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When it needed to use a commercial locomotive builder, the Pennsy favored Philadelphia's Baldwin Locomotive Works over all others. Baldwin was a big PRR customer, for one thing -- its raw materials were delivered by the PRR, and its finished products were shipped over PRR metals also. That the two companies were headquartered in the same city certainly had a bearing - PRR and Baldwin management and engineers knew each other well. The second preference, when both the PRR and Baldwin shops were at capacity, was the Lima Locomotive Works in Lima, Ohio. Only at a last resort, it seems, would the PRR use Alco, the American Locomotive Company, based in Schenectady, New York - serviced by and favorite locomotive supplier to the Pennsy's arch rival, the New York Central Railroad.

Related Topics:
Philadelphia - Baldwin Locomotive Works - Lima Locomotive Works - Lima, Ohio - Alco - American Locomotive Company - Schenectady, New York - New York Central Railroad

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The PRR had a definite style that it favored in its locomotives. The square-shouldered Belpaire firebox was a PRR trademark that otherwise found little favor in the United States; almost every PRR locomotive had it. It traded more difficult construction for a greater heating surface and simpler firebox staying. The PRR used track pans extensively to pick up water on the move, so the tenders of their locomotives had a comparatively large proportion of coal (which could not be taken on board while running) compared to water capacity. The PRR was wary of gadgets and its locomotives were not generally festooned with devices; the PRR also favored a neat mounting of such devices when necessary, leaving the lines of the locomotive comparatively clean. Smokebox fronts bore a round locomotive numberboard (freight) or keystone numberboard (passenger) and were otherwise uncluttered except for a headlamp mounted at the top, with a steam-driven turbo-generator behind it. In later years the positions of the two were reversed, since the generator needs more maintenance than the lamp.

Related Topics:
Belpaire firebox - Track pan - Tender

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The PRR, until its final years, preferred a philosophy of smaller locomotives rather than buying the biggest.

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Each class of steam locomotive was assigned a class designation. Early on, this was simply an alphabetical letter, but when these began to run out, the scheme was changed so that each wheel arrangement had its own letter, and different types of the same arrangement were defined by a subsequent number. Subtypes were in turn indicated by a lower-case letter; superheating was designated by a "s" until the mid 1920s, by which time all new locomotives were superheated. Thus, for example, a 'K4sa' class was a 4-6-2 "Pacific" type (K) and of the fourth class of Pacifics ordered by the PRR. It was superheated (s) and was of the first variant type (a) after the original (unlettered). See PRR locomotive classification for details.

Related Topics:
Wheel arrangement - 4-6-2 - PRR locomotive classification

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