ModelTrainStuff is celebrating the 120th anniversary of the Pacific-type locomotive, wheel arrangement 4-6-2!
The Pacific dominated high speed passenger service and express freight service in the United States from 1902 through 1950 until steam locomotives surrendered to Diesel-Electric locomotives. The Missouri Pacific was the first US buyer in 1902 and accordingly the 4-6-2 was christened the “Pacific” type. Immediately after, the MP locomotives the Chesapeake & Ohio purchased a small group of identical locomotives.
Design of the Pacific Type Locomotive
In 1887 the Lehigh Valley added a small trailing truck to a Ten-Wheel locomotive as an experiment to support a larger patented Strong Firebox. In 1889, the Milwaukee Road assembled a similar experiment in an effort to reduce axle load. But both designs were considered to be “modifications to an existing locomotive” rather than a completely new design. So railway mechanical officers and locomotive historians do not consider either locomotive to be the first real pacific-type.
The first true Pacific was ordered in 1901 by the New Zealand Railways Department from the Baldwin Locomotive Works. A larger firebox was added to burn coal more efficiently and provide more steam. Baldwin Locomotive salesmen quickly marketed the advantages of the Pacific-class to customers world-wide.
The timing for the new design was perfect in every way. After a modest start with the MP and C&O locomotives, other US railroads quickly embraced the 4-6-2 to keep up with the increasing train lengths and speed demands. New York Central Lines affiliate Lake Shore & Michigan Southern quickly abandon their fast Prairie-type locomotives (2-6-2) and embraced the 4-6-2 for powering the 20th Century Limited.
The Pennsylvania Railroad tepidly experimented with the 4-6-2 wheel arrangement and did not fully embrace the design until after four years of testing. By the 1920s, PRR added superheaters to the class K locomotives, and the letter “s” was added to the classification. By 1928, PRR rostered 425 class K4s locomotives and owned more 4-6-2 locomotives than the Missouri Pacific had in their total locomotive fleet.
Soon most name-passenger trains in the US were powered by 4-6-2 locomotives that were designed by American Locomotive Company, Baldwin Locomotive Works, Rogers Locomotive Works, and Lima Locomotive Company. However many Pacific locomotives were deigned by the Mechanical Officers of the larger railroads.
Railroads including B&O, N&W, Lehigh Valley, PRR, Reading and Southern Pacific also maintained extensive shops that could build locomotives from the ground up. This specialized uniqueness lead to a bunker mentality that ignored “standardization” and hampered railroad efficiency.
A New Era for Pacific Locomotives
The 1920s and 1930s were the glory years for Pacific locomotives. It was the most colorful era of traditional railroading to increase the visual impact of their best passenger trains. The Overland Limited, Empire Builder, Sunset Limited, Crescent Limited, Florida Special, The Blue Comet, North Coast Limited and the Pioneer Limited are just a sampling of the great US passenger trains that were powered by 4-6-2 locomotives. Several railroads, including the Erie and PRR, regularly used 4-6-2 locomotives to power refrigerator-express trains as well.
When the streamlined passenger trains became vogue, some railroads commissioned leading industrial designers to develop streamlined exteriors for older 4-6-2 locomotives. This powered the modernized and lightweight streamlined passenger trains. B&O locomotive #5301 is known for having two different streamlined shells installed first for the 1937 Royal Blue. And in 1956, the B&O #5301 was the last streamlined 4-6-2 in daily service. Several railroads, including the C&O, extended the life of serviceable Pacific locomotives by rebuilding them into more powerful 4-6-4 locomotives. The C&O #490 on display at the B&O Railroad Museum in Baltimore is a perfect example of this!
The Demise of the 4-6-2 Locomotive
Two major factors signaled the demise of the 4-6-2 locomotives.
It was initially air-conditioning followed by modernized heavyweight Pullmans (both introduced in the early 1930s). The 4-6-4 (Hudson), 4-8-2 (Mountain) and 4-8-4 (Northern) wheel arrangements were better suited to power the newer, longer and heavier trains. PRR maintained the 4-6-2 locomotives longer before being forced to double-head most of its name-trains until the late 1940s.
The second was the evolution of the Diesel-Electric locomotive in the late 1930s. Passengers welcomed the smooth starting qualities of the Diesels and the cleanliness throughout. Railroads rapidly saw the efficiency of that pace-setting motive power.
By the early 1950s, most railroads had retired the 4-6-2 locomotives, and by 1956 the PRR was among the last operators of the Pacific locomotive. Fortunately, several Pacific locomotives have been preserved as a tribute to that class.
Shop our selection of 4-6-2 locomotives and bring the 120 year old legacy into your layout!