Pittsburgh’s H. K. Porter established a reputation as a builder of rugged, specialized locomotives for small industries and short line railroads. It could custom-build a steam locomotive quickly and efficiently through a system of interchangeable parts—pistons, wheels and boilers in various sizes—that could be combined to suit a customer’s specific requirements. Among Porter’s product offerings were compressed-air locomotives, having cylindrical tanks that stored pressurized air from an external source which was used instead of steam to move the engine. This allowed locomotive use inside enclosed areas without the fumes, heat and sparks associated with burning coal. Porter built more than 400 compressed air locomotives for use in mines, factories, textile mills, refineries, munitions plants, food handlers, sugar cane plantations and even the street railways of New Orleans.

A typical Porter compressed air engine had one storage tank containing 800 – 1200 pounds-per-square-inch air which would pass through reducing valve to depressurize the air down to about 150 psi at the cylinders. Larger air locomotives were “compound” with the high pressure air used to move one cylinder and then exhausted to the other side of the locomotive to move a lower pressure one. Such two-stage engines employed an air reheater between the two piston stages to warm the now cooled compressed air. The reheater was warmed by ambient air drawn through it by using the low pressure exhaust air in an ejector. 800 psi is significantly more pressure than used in typical steam boilers, which rarely exceeded 300 psi. For this reason, air locomotives were constructed with inch-thick steel tanks held together with large rivets, giving them a unique look. A compound loco operating on a sugar plantation could haul 13 carloads of cane seven miles on one charge of compressed air, and saved paying the wages of a fireman and $10 worth of coal during each day of operation.

In 1915, Porter built a large, three-tank, air locomotive for use on a sugar plantation in Camaguey Province in Cuba. It was designated as a class “B-PPP”—the “B” means that it has an 0-4-0 wheel arrangement, “P” stands for “pneumatic” and the three-P symbol “PPP” indicated that the locomotive had three tanks or cylinders containing the compressed air. This particular loco was ordered by Dibert, Bancroft & Ross, a large Louisiana iron foundry that manufactured, among other things, machinery for the processing of sugar from cane. With its first attempt at standardization, during 1915 the company designed, constructed and completely equipped four ingenios azucareros (sugar mills) in Cuba for the Palma Sugar Company, whose principal owner at that time was none other than General Mario G. Menocal, el presidente of Cuba. He nixed the use of old-fashioned, steam-powered machinery of any kind on the ingenio, and ordered that electric motors be used throughout the new sugar processing installation.

On November 6, 1915, No.1 was placed onto a flatcar at the H.K. Porter shops in Pittsburgh, and went directly to New Orleans where it was loaded aboard a ferry for the sea voyage to Cuba. Delivered to the ingenio on December 16, this was the first compressed air locomotive of its type used anywhere in Cuba. A three-inch pipeline was laid along the seven miles of track out in the cane fields so that this lokie could be recharged whenever it needed a fresh supply of compressed air. For the first time fears of fires consuming contiguous fields of cane were unfounded, as the new compressed air locomotive performed flawlessly with no flying sparks because there was no fire.

This odd-looking machine was repatriated back to the United States sometime after 1921, and during 1935 was working for the New Orleans Sewage & Water Board where it switched freight cars. After being retired, No.1 was placed on display in Mel Ott Park in Gretna, Louisiana. This compressed air locomotive was acquired by the Louisiana Steam Train Association before being sold to the Age of Steam Roundhouse. It arrived by highway truck at the roundhouse on November 10, 2015, and was plucked from its trailer by our 30-ton capacity shop crane (the heaviest object it has ever lifted) to be set back on the rails. Number 1 won’t be running anytime soon, as our air compressors do not generate enough pressure to make this critter crawl.

Several smaller compressed air locos survive from the mining industry, but No.1 is believed to be the only standard-gauge compressed air locomotive surviving in the U.S. It is certainly the sole remaining Porter three-tank compressed air locomotive in the United States, if not the world, and is one of the most unique engines in the AoSR collection.