The Triplex

Mallet locomotives were articulated; that is, they had at least two sets of drivers, one of which could swing free of the boiler, allowing a very long and powerful locomotive to make its way around fairly tight curves with the boiler overhanging the curve.  They also reused steam from one set of cylinders to another.  The version of the Mallet in this video, the Triplex had THREE separate steam chests and drivers, on the theory that if two were good, three would be better.  The Erie had three of these 2-8-8-8-2 locomotives.  The theory did not long survive the reality, as the boiler was unable to produce enough steam to power all six cylinders and after going only a relatively short way, the locomotive slowed down and came to as stop as it ran out of steam and then had to sit and wait until it built up a head of pressure again.  In 2002, MTH brought out a Premier model of the Erie Mallet.  As you'll see in the video, the detail is exquisite, the sound is great, and it operates beautifully.  It's one of the gems of my collection.