General LeRoy Stone's Centennial Monorail.

Updated: 27 Nov 2007
Back to Home PageBack to The Loco Index
Left: General LeRoy Stone's Centennial Monorail of 1876.

This stereo photograph is the only known image of the Centennial Monorail, a double-decker design driven by a rotary steam engine. It was operated as a novelty at the Centennial Exposition

Picture kindly provided by Robert M Vogel.

General LeRoy Stone's steam monorail first appeared at the Centennial Exposition marking the USA's 100th anniversary in 1876. An elevated track extending about 170 yards was built in Fairmont Park in Pennsylvania. It connected the Horticultural Hall with the Agricultural Hall, and appears to have been called "The Saddleback Railroad".

The elaborately decorated double-decker vehicle had two main wheels; the rear wheel was driven by a rotary steam engine of the La France type. By this date it must have been clear that rotary steam engines were inefficient, but this monorail was more of a fairground attraction than a demonstration of exemplary thermodynamics.

This design clearly solves The Monorail Problem (ie how to avoid falling off the rail) by means of the guide rails visible at the level of the front steps. The square structure at the rear is the driver's cab, with a short funnel protruding, and smoke and steam visible.

Some drawings of this monorail locomotive have now been discovered, in Edward Knight's Mechanical Dictionary. (Supplementary Volume 1884) For some unknown reason Knight makes no reference to General Stone or the Centennial Exposition, but simply describes it as a "single rail railway", without naming the inventor. However, there can't have been that many rococo-style monorails running around America at the time, so I am pretty sure it is the same machine.

Left: Knight's Monorail drawing.

This drawing combines a front view, on the left, with a section of the passenger compartments on the right; seating was on two levels.

The double-flanged vertical wheel on the bearing rail A takes the weight while the two double-flanged horizontal wheels D run on the side rails B to give stability. The side rails were 4ft 5in below the bearing rail.

From Knight's American Mechanical Dictionary, Supplementary Volume 1884.

Left: Knight's Monorail drawing.

This shows the rear of the vehicle, with the boiler, rotary engine, and square driver's cabin. The La France type rotary engine is at the left, driving the vertical wheel C directly. The driving wheels were of 28in diameter.

The boiler was of the locomotive type, 12ft long and 34in in diameter. Water tanks can be seen at E, with coal heaped in front of them.

From Knight's American Mechanical Dictionary, Supplementary Volume 1884.

A modified version of LeRoy Stone’s design was used on a four-mile line between Bradford and Gilmore, Pennsylvania.
See The Bradford Monorail.

Back to Home PageBack to The Museum EntranceBack to The Loco IndexTop of this page