Sinnemahoning Valley Other Articulated Locomotives in the USA

Class Edward T Johnson (Locobase 5310)

For data see AB Eddowes, "Some Unusual Locomotives", Proceedings of the Engineers' Club of Philadelphia, Vol XVIII, (Philadelphia, Pa: , 1901), pp.305-307. [] (visited 6 Jan 2003) for details. See also DeGolyer, Volume 17, p. 162. Works number was 12526 in March 1892.

This is one of the most unusual locomotives in Locobase, a Meyer engine with Vauclain-compound cylinders. It was a relatively small engine.

Locomotives of the Meyer design carried two engine sets under a single boiler with the cylinders facing to the rear in each set. Many Meyers used simple expansion, but powering each set of drivers (two per side) on this locomotive was a unit of one HP and one LP cylinder, both fed by a single valve. (The only other eight-cylinder locomotive in Locobase is a Garratt operated by a Tasmanian railway; see Locobase 796.)

Eddowes described the specification that led to this design:

"The conditions which led to the construction of this locomotive were a railroad with a grade of 575 feet per mile, or 10.89 per cent., with curvatures of 40 degrees, or about 143 feet radius. The track was laid on stringers, which in turn rested between crosstics about 20 feet apart, the stringers being made of rough logs. There was allowed a maximum weight per pair of stringers of 35 to 40 tons, and in order to get a heavier locomotive than 40 tons a wheel base of over 20 feet was necessary in order to avoid overloading the stringers."

In other words, instead of a ballasted bed with hundreds of ties per mile, the track on this grade had longitudinal support under each rail for its entire length with stretchers every 20 feet to cut down on the wandering gauge.

Designed specifically for logging operations, it quickly became redundant when the Sinnemahoning was almalgamated with 3 other logging roads to form the Buffalo and Susquehanna. Although it was given the #103, the B & S very soon returned the engine to Baldwin, which scrapped it.