I recently bought a copy of Classic Trains Special Edition titled, Fantastic 4-8-4 Locomotives- Fast, powerful, versatile, giants from the zenith of steam. This is a first for Classic Trains, the entire length of the magazine is dedicated to this wheel arrangement. The writers go in-depth explaining what made the 4-8-4 the great locomotive many railroads, railroaders, and rail historians believe they were. Myself being a fan of the Pennsylvania Railroad, have never considered myself to be a fan of the 4-8-4 type. In fact the Pennsy was one of only nine big roads that didn't use the 4-8-4 type. After reading the articles in this issue I have still hold true to my position that the 4-8-4 type was an over-hyped locomotive and far too many of them remain in excursion service.
The "Super Power Era" was started in the 20's by the Lima Locomotive Works. The idea of super power locomotives was to increase the size of the firebox and combustion chamber so that more heat could be generated allowing for more power. The increased firebox size forced designers to place a two axle trailing truck underneath to support the size and weight of the enlarged firebox. Complete new wheel arrangements were developed using this concept. The 2-8-4 Berkshire, the 4-6-4 Hudson, the 2-10-4 Texas, the 2-6-6-6 Allegheny, and the 4-6-6-4 Challenger. These locomotives were known for providing high horsepower for speed AND being able to pull heavy trains. Most people think the 4-8-4 was a product of this "super power concept" if you follow the table below it makes perfect sense:
Drag Freight: Super Power:
2-8-2 Mikado........................2-8-4 Berkshire
4-6-2 Pacific.........................4-6-4 Hudson
2-10-2 Santa Fe....................2-10-4 Texas
Naturally Lima should have added another axle to the trailing truck of the 4-8-2 Mountain type making it a 4-8-4 Northern. But this is not the case. In 1926 the Northern Pacific railroad designed a new locomotive. Requirements for this locomotive was that it was to burn the low grade "Rosebud" coal that was available to the Northern Pacific (NP). Like Anthracite coal Rosebud coal would require a greater grate area than high quality Bituminous coal. Designers developed a firebox of 115 sq ft. The size of the firebox was too large for a single axle trailing truck to support. So designers rolled a two axle truck underneath to support the firebox. Along with four driving axles and four pilot wheels the 4-8-4 was born. The American Locomotive Company was contracted to construct the first 4-8-4 which the Northern Pacific dubbed, Northern Pacific type. This was later shortened to Northern.
By the end of the steam era total production of the 4-8-4 type had reached 1,125 locomotives, for 36 different railroads. The 4-8-4 types arrived on railroads late in the steam era. The 4-8-4 type was the last new wheel arrangement developed by some railroads. For many they were the last steam locomotives to arrive before being replaced by the diesel electric locomotives.
The 4-8-4 is considered by many railroad historians to be among the most modern steam locomotives ever built. The 4-8-4's had a host of modern appliances that allowed them to get every ounce of usefulness out of the steam they produced. 250 psi boiler pressure became the norm, type E superheaters increased superheating surface by 30 percent over the type A superheaters. Large combustion chambers allowed for complete combustion of fuel providing more heat. Thermic syphons enhanced heat transfer. Feed water heaters increased boiler capacity by 8-10 percent. The entire locomotive rod on a cast steel engine bed, which solved problems with parts being vibrated loose thanks to the pounding of heavier rods. In some cases roller bearings were added to 4-8-4's designed for passenger use.
There is no denying that the 4-8-4 was at the top of its game when railroads realized that the diesel electric locomotive was the way of the future. The true potential of the 4-8-4 will most likely never be known for testing of steam locomotives virtually stop once railroads focused their research teams on diesel electric power. But why is the 4-8-4 given so much credit?
One may say that the 4-8-4 combined everything that has been learned over the years about steam locomotive design and building. Different components that made the 4-8-4 so modern and advanced have been developed and tested on earlier locomotives before they were all "mashed" together on a boiler riding on a 4-8-4 wheel arrangement. No one ever clearly states this, the magazine makes it seem like all these advanced appliances attached to the 4-8-4's were developed just for the type.
Would a 4-10-4 been as successful? We will probably never know. What I do know is reading an entire magazine dedicated to a locomotive type that made up only 3% of the total locomotives constructed in America doesn't seem right. The small lonely 4-4-0 reached 25,000 locomotives. Those locomotives were the real pioneers of the industry. Lessons and methods learned while designing, constructing, operating, and maintaining those locomotives undoubtedly help lay the ground work for locomotives to follow, including the beloved 4-8-4.
I'm not going to sit here and say that the 4-8-4 type were bad locomotives. They got the job done and combined the best of steam locomotive technology onto one boiler. There are other locomotives that were built towards the end of the steam era that tried to do just that, but were overall failures. A number of 4-8-4 types are currently operating in excursion service in the United States. They provide riders with a high speed smooth ride and the only way to experience mainline steam railroading in the "diesel" world of today.
-Donnell E. Allen
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| Southern Pacific's Lima built 4-8-4, GS4 |
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| Reading's home built 4-8-4, T1 |
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| Norfolk & Western's Home built 4-8-4, J |
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