Engineers and Mechanics Encyclopedia 1839: Railways: George Millichap

In the course of this article, we have described a variety of ingenious contrivances for enabling locomotive carriages to pass over obstacles lying in the road, without injury resulting. The invention we have next to notice is of that description, and is the subject of a patent granted to George Millichap, of Birmingham, and sealed on the 31st of March, 1834.

The carriage is mounted upon three pair of wheels, whereof the foremost and the middle pair are situated in their usual places in four-wheeled carriages; but the additional third pair, herein alluded to, are quite at the back, and much nearer together than the others. The fore wheels are made to lock much in the usual manner, and above them in a framework, carrying toothed gear, by which the carriage is steered, when acted upon by the guide, through the medium of suitable levers.

The axis which carries the middle pair of wheels, passes through projecting arms at the fore extremity of the principal platform or floor of the carriage, which platform rests upon the axletree of the hind wheels, about two-fifths of its length from its hind extremity. Should an obstacle therefore present itself against the middle pair of wheels, (and a very formidable one is shown on the drawings of the specification,) it does not become necessary to lift up the whole weight of the carriage and load, but only rather more than the weight of the wheels, as the axletree of these acts like a hinge joint, and the platform of the carriage yields to the resistance, by collapsing, or turning upon its joints. For the sake of illustration, a train of gear, of different speeds, are shown as worked by hand; but the patentee observes, that steam power may be obviously communicated to it, in lieu of manual labour.

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