The online magazine on the history and operation of vintage scale model trains in American OO gauge

Saturday, January 3, 2009

75 years of the Nason P5A

The Nason P5A, the first commercially successful OO gauge locomotive, was released in 1934. Below is the one in my collection.

Besides this year being the 75th anniversary of this important model, OO enthusiast Edward Havens forwarded a note he wrote for the Philly Traction Yahoo group, as today is also an important date in prototype P5A history, a locomotive somewhat overshadowed in modern railfan and model railroad circles by the GG-1. Ed provided this link is to a photo of the prototype in operation. With that I will turn the rest of the post over to Ed--thank you for putting together this background information.


They were the workhorses of Pennsy electrification and it's appropriate to recall them because of an historical date: Jan. 3, 1934. On that date 75 years ago, P5A boxcab motor No. 4772 was barreling across New Jersey, hauling PRR varnish, the "Spirit of Saint Louis." There were a dozen all-steel baggage, combination, passenger and sleeping cars on Train No. 31. The afternoon train was 40 miles southwest of Penn Station, approaching a crossroad with destiny. Just as PRR electrical engineers intended, the motor whined with power as it hurdled toward Deans, N.J., and a grade crossing guarded by a watchman. His waving red flag was ignored by a 1929 truck loaded with 220 baskets of apples. The crossing guard watched in horror as the driver attempted to run the crossing at 40 mph. The truck and its cargo weighed 10-1/2 tons. 100 feet away loomed Train No. 31 – with motor and passenger cars weighing 1,096 tons.

The outcome was inevitable. The highway truck was virtually vaporized. The collision with the boxcab motor killed the engineman at the head end controls. The fireman survived but only because he was at the rear of the motor, attending its train-heating boiler. Truck driver Joseph Wallad was hurled into a field and died before an ambulance dispatched from New Brunswick could arrive. The "Spirit of Saint Louis" went into emergency braking because the motor's air line broke. The P5A and the first four cars continued rolling, stopping more than ½-mile southwest of the grade crossing. The other eight cars, detached from the rest of the train, came to a halt 900 feet behind.

But that wasn't the end of mishap on the four-track line, today's Northeast Corridor [NEC]. The collision impact, which crunched the front cab of the P5A, separated one of the highway truck's tires from its rim. It came to rest on Track 1, just as a steam-powered Atlantic City to New York train approached from the south. K4s 4-6-2 Pacific No. 1984 hit the tire, which wedged itself below the steam locomotive's pilot truck, derailing it. The K4s with its six passenger cars left the rails and ground to a stop. No one aboard express train No. 1072 was injured.

The accident – and deficiencies discovered with the operation of the original design of boxcab motors -- led to redesign of the P5A class by PRR's mechanical and electrical engineers. By March 1932, PRR had 62 boxcab P5A motors in service. Another 28 had been ordered but had not yet been delivered. In December 1934, PRR's Altoona shops unveiled its modified P5A, somewhat resembling a "vest pocket" GG1:

PRR for some reason did not give the modified P5A its own sub-class on the company's locomotive roster. Railfans called them "Modified P5A" but PRR corporate records show only two official designations:
-- Streamline P5A
-- P5A built after May 1, 1934.
In comparison with the GG1 class, some PRR employees referred to the modified P5A as "puddle jumpers."

By the time the modifieds went into service, PRR main line electrification extended from New York to Paoli, via Philadelphia, and to Wilmington, Del. Catenary would not be extended from Wilmington to Washington, D.C., until February 1935, and from Paoli to Harrisburg until January 1938. In passenger service, the modified P5A had even faster acceleration from a dead stop than the first group of GG1 motors, anecdotal evidence suggests. The modified P5A design had better weight distribution than the boxcab predecessors resulting in improved high speed operation. But the GG1 proved to be a superior locomotive and so the P5A class was relegated to freight service. By 1959, 91 P5A motors -- both boxcab and streamlined -- remained on the PRR roster and the projected life of the modifieds only had been 20 years. To replace them, PRR in 1959 ordered 66 E44 motors, rated at 4,400 horsepower, from General Electric:

With the arrival of the E44 motors, PRR began to retire the aging P5A class. The modifieds were scrapped first; all were off the roster by 1963. The reason: their streamlined shells made them more costly to maintain. The final group of boxcab P5A motors were sent to the scrappers by April 1965.

But what about that boxcab displayed at National Museum of Transportation at St. Louis, Mo., you ask? Answer: it isn't a P5A. There were two other sub-classes of boxcab P5 motors. The two prototype locomotives were Nos. 7898 and 7899, later re-numbered into the 4700 series. The demonstrators built for evaluation were class P5. Altoona shops built the pair, which debuted in August 1931. Their original roster numbers lasted only one month. In September 1931, the duo became Nos. 4700 and 4791, respectively. No. 4700 was donated by PRR to the National Museum of Transportation:

The other representative of the P5 classes was No. 4702, which became a P5B. It was a unique, one-of-a-kind experiment to increase tractive effort. The other P5 classes were 2-C-2 motors, the electric locomotive version of a 4-6-4 steam locomotive wheel arrangement. The P5B had powered pilot trucks with a 375 horsepower motor mounted on each truck, creating a B-C-B wheel arrangement. Ballast also was added to improve weight distribution of No. 4702. The conversion of the P5A boxcab into class P5B only resulted in a marginal increase in locomotive performance. The cost was deemed unjustified for the resulting hauling ability so no additional P5A class motors were converted into P5B configuration:

The P5A was featured in the 1934 PRR corporate calendar in a painting by artist Grif Teller. No. 4702 was featured. The calendar art was titled, "The New Day." It was the only time a P5A was included in a PRR promotional calendar:

Material for this post was adapted from two Pennsylvania Railroad Technical & Historical Society publications: the soft cover book "The Pennsy's P5 Electrics," by Frederick Westing, Mike Bezilla and Roger L. Keyser, published in 2002; and from "The Keystone" magazine, Vol. 33, No. 3, Autumn 2000, from an article titled, "A Brief History of the Pennsylvania Railroad MP54 Multiple-Unit Cars," by Charles Hulick. See this PRRT&HS page for ordering:

1 comment:

Bruce Smith said...

I came across this blog post via the link to what you appear to think is a P5a modified (or perhaps a GG1?). However, the loco in that photo is neither. Rather, it is the one of a kind R1, the only 4-8-4 ever rostered by the PRR and the loco that was built at the same time as the GG1 in the "great locomotive competition", which the GG1 won.