The Raub Central Power Locomotive

Gallery opened: 18 Nov 2014

Updated: 7 Mar 2015
Patent drawing added
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This strange locomotive was designed by Doctor Christian Raub, of New York city, who was supposed to be "a prominent and able railroad engineer", though the second adjective at least is disputable. The advantages of having a double-ended boiler and vertical cylinders are not immediately obvious, and I can only quote from the Scientific American article (Oct 15, 1881) that announced it:

"The object of this invention is to construct a perfectly balanced locomotive, in which the center of gravity is coincident with the vertical median line of the engine, and in which the motive power is located at the middle of the engine in a plane extending through the center of gravity. These two objects being attained, it is hardly possible to overestimate the value of the invention, since the locomotive will then be constructed upon correct principles and according to natural laws. It works from its center, and has its motive power situated in a plane extending through its center of gravity, and has therefore no dead weight."

This is less than informative, and there seems no point in trying to guess what line of reasoning the inventor followed to end up here.
What is certain is that vertical cylinders were recognised to be A Bad Thing very early in the history of locomotive design, because the up-and-down reaction forces meddled directly with the gravitational force (ie weight) holding the wheels against the rail and giving adhesion.

Left: The Raub Central Power Locomotive: 1881

The Raub was designed to be symmetrical about its center of gravity, though what benefits this might offer is unclear. There were two separate firetube boilers, each with its own firebox. The hot gases came back to the middle of the locomotive via return flues, and were combined in a single chimney. Note the step-ladder required to get from one side of the boiler to the other.

It is not clear from this image how the vertical cylinders connected with the wheels, but the patent shows a common crankshaft driven by the two vertical cylinders, and coupled to the wheels. The inner pair of axles can be seen here joined by a coupling rod. I suppose this counts as a form of jackshaft drive, which has its own gallery.

Water was carried in tanks under the frames, with cutouts to allow the axles to pass through.

The critics were merciless.

Angus Sinclair, in Curiosities of Locomotive Design. (From Development of the Locomotive Engine, Railway and Locomotive Engineering, September-December 1907, had this to say:

"When locomotives of this character (this seems to have been a reference to geared or jackshaft drive) have been built by men seeking for the best form of engine to perform the work of train hauling, their efforts were commendable, but at various times amateur locomotive designers, saturated with egotism and personal conceit, have produced ridiculous engines and sometimes their friends have tried to force them into use through stock-selling operations. (Probably a reference to the Holman scam) A notable case of this character was the Raub Central Power locomotive, Fig. 9, built at Paterson, N. J., in 1892. The people interested in this invention tried to push it through the influence of sensational articles in the daily newspapers, their claims for speed and efficiency being senseless exaggerations, but their efforts were in vain. As usual, they blamed its unpopularity upon the prejudice of railroad men and the engineering press. The engine had two small boilers, each with a fire door on each side and a smoke flue going back to the stack in the centre."

"Vertical cylinders were employed, transmitting the power through a central shaft. This engine was not only an oddity, it was a fake of the worst kind. Instead of an advance in design, it was returning to pioneer practices, being a product of combined ignorance, egotism and perversity."

Note that Sinclair says it was built in 1892; 1881 seems to be just the date of the patent. It appears to have been built by the Grant Locomotive Works of New Jersey. What happened to it after that, if it was tested, and if it really was a deliberate stock-market swindle rather than just a pointless and inept invention, so far remains obscure.

Left: The Raub Central Power Locomotive: 1881

A section through the boiler. The hot gases moved from the firebox to the far end of the boiler through the small tubes at the bottom, then returned via the four upper tubes to the central chimney. Note that the upper tubes are only just covered by water, which looks dangerous to me.

Left: The Raub Central Power Locomotive: 1881

Internal view of the boiler, with firebox accessed via the oval firedoor in the side, and a large return flue at the top taking the gases back to the chimney. A large domed steam space surrounds the central chimney.

Left: The Raub Central Power Locomotive: 1881

This drawing shows a rather different wheel arrangement, in which all four axles are driven from the jackshaft.

Above: The locomotive design was covered by US patent 247,108 issued to Christian Raub in 1881.

However the patent drawing appears to show two separate chimneys D',D' for each boiler instead of one central chimney. The jackshaft is barely visible at B, once again only driving two axles.

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