H.K. Porter Locomotive Company was an innovative leader in the specialty small locomotive marketplace. Able to assemble engines quickly from off the shelf components to meet customer needs, they built engines that were used by construction contractors on large projects like road and railroad construction and industrial switching engines. An example of their saddle tank switching engines was featured in the Nov. 1 2017 post, E & M Number 5 Turns 100.
As versatile as their small locomotives were, there were situations where they just wouldn’t do. Coal mines, factories producing hazardous and flammable materials and confined spaces where the byproducts of combustion would be unacceptable needed motive power that didn’t spew smoke and sparks. In 1890 Porter made a bid to capture this market by introducing a two stage compressed air locomotive. By 1930 400 copies had been sold. The compressed air engines filled the need,but they had extremely limited range and endurance.
In 1915 Porter developed a steam storage locomotive that offered significant advantages over compressed air engines. This design consisted of a large capacity insulated tank that was filled with superheated water and steam supplied by any existing stationary industrial boiler. Steam from the tank was tapped from the steam domes and piped to a standard piston engine that turned the driving wheels. This siphoning off of steam reduced the pressure in the tank, allowing more steam to boil off from the water. Applying this well known principle of physics, greatly increased the amount of steam available for work above what could be obtained if the tank was filled with steam alone. Once the tank was filled, the engine could operate from 2 to 5 hours, depending on the load.
There were many appealing advantages to this system. Since most factories and other industrial sites already had a ready supply of steam available, eliminating the cost of the firebox and boiler on the locomotive represented a significant savings. Add to that the savings on fuel and the cost of labor of a fireman on the locomotive since the engineer could operate the locomotive by himself. It takes a considerable amount of time and fuel to bring a locomotive boiler up to operating temperature and this requires the attention of the engine’s crew. The steam storage engine on the other hand could be charged in a few minutes. When the locomotive was not moving freight it could be parked and the operator could perform other tasks. There were also savings in maintenance cost.
Shortline railroads operated by a variety of business ventures put these fireless locomotives to good use. I found a photo at www.over-land.com of a Porter fireless engine being used at the Apache Powder Co. plant near Benson Arizona. It doesn’t take a lot of imagination to see the advantage it would have, working in a dynamite factory. Power plants were another natural application since they already possessed an abundant supply of steam and that is where the locomotive shown here spent it’s working years.
H.K. Porter built this 0-4-0 switch engine in 1937. It was operated by Carolina Power and Light Co. at the Lumberton, North Carolina generating plant where it hauled car loads of coal, cinders and ash until it was retired in 1980. It was donated to the state of North Carolina in August of that year and later moved to the Transportation Museum where it is currently on display.
Sources:
www.nctrans.org
www.cstrains.com
www.over-land.com
Locomotive Cyclopedia of American Practice Vol. 6 at https://books.google.com
www.ageofsteamroundhouse.com
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