The Triplex


Daniel Franchetti, 8th Grade Contributor

The triplex locomotive was an experimental steam locomotive that had the power to move mountains. It could amass a force of 710000 Newtons. The locomotive was gigantic but could not surpass the speeds of a running man. That being said, the 2-8-8-8-4 (2 leading, 3 sets of 8 large driving, and 4 trailing wheels) could only reach 5mph and the 2-8-8-8-2 could rarely make it to 10mph. Their purpose was to push trains over tall hills. This was called a banker engine. I discovered this locomotive only recently, and its traction power and size attracted me to it at once.

Triplex means there were three sets of driving wheels. The locomotive’s fire box took up a solid third of the actual locomotive, and even than it couldn’t supply enough steam to get it moving fast. It consumed steam like a starving beast which resulted in traction power but low speeds. Only four of these where made and they were all scraped. Plans had been made for a 2-8-8-8-8-2, 2-8-8-8-8-8-8-2, and a 2-10-10-10-10-10-2 (52 wheels!). However, due to the poor performance of the 2-8-8-8-2s and the one 2-8-8-8-4 those plans for larger locomotives were not executed. The 2-8-8-8-2 could theoretically pull 650 trucks with its power. The cost of coal and water were too heavy so they only lasted from 1914-1933. An interesting idea for train fans to rest on is that these locomotives are the longest tank engine. Meaning they have no separate tender to hold coal and water. The last set of driving wheels came into what would be called a tender making it part of the locomotive and thus, no longer a tender. It just looks as if it were a separate tender.

The idea of larger models of the 2-8-8-8-2 would have been a sight to see. Just imagine, a 2-10-10-10-10-10-2 might have rivaled the power of a modern diesel electric locomotive in terms of traction. While the design was scraped, the

capability that the locomotives showed were beyond belief. It is really unfortunate that the none were preserved. The triplexes were an excellent example of American engineering and experimentation making them one of my favorite American locomotives.