To prevent locomotives running off their lines of rails, Mr. G. A. Kollman proposed (by his patent of 183(5) to attach a vertical arm or bracket underneath the carriage, furnished with anti-friction rollers, that bear laterally against a central rail, to be placed midway between the ordinary rails. He proposed two modes of effecting this, which differ but slightly from a variety of suggestions of the same kind, and for the same object, but as there were strenuous efforts made a short time since to get Mr. Kollman's plans adopted on certain lines, we feel it incumbent upon us to give a brief description of them. The first mode was to form a trench with a metallic case to it below the surface of the road, and to cause the anti-friction rollers to act against the sides of the case; the second was to fix a middle guide rail above the .ground and cause friction rollers to operate on each side of it.
In the annexed cut Fig. 1, is represented at a the vertical arm, extending from the under part of a rail-road carriage; to which arm, as an axle, an antifriction roller b is attached; c is the metallic case to the,trench; against the sides of which the roller is intended to act, as the carriage travels along, the wheels of which are restrained from running off the rails, by the flanges d d not permitting the carriage to rise.
Figs. 2 and 3 are explanatory of the other mode mentioned. At a is the vertical arm; b, b the antifriction rollers acting against the sides of the middle rail c as the carriage proceeds, the broad top d of the said rail keeping the rollers in their places and preventing the carriage from rising. For the better guidance of the carriage in its true course, there are to be two pair of rollers b, b, placed at a short distance one before the other, and mounted in a frame of the kind delineated in the annexed Fig. 3.
The patentee appears to be aware of the paucity of originality in his scheme, and confines his claim to invention in the application of the "top flanges, to prevent the carriage rising." - London Journal, for July, 1841.