The sledge or retarder a is formed like a wedge, with its superior end turned up; upon the inner side, flanges are formed, so as to keep it upon the rails; the two sides are united together by the cross bar j, the plate k, and the cross pieces g g, and the sides are set to the same gauge as the rails, so that an engine may run upon it without difficulty; to the cross bar j, two buffers d d are fixed, which correspond with other buffers I, formed upon the front frame of the engine, so that when the engine comes in contact with the retarder, these buffers receive the concussion; the plate k is used in order to unite the sledge as near to the point as possible, and still to allow a free passage to the flanges of the wheels. To the cross pieces G G the spring pieces b b are fixed, forming shafts for the wheels c c, upon which the apparatus is carried when out of gear. e is a weight to counterpoise the weight of the sledge, so that a man can move it along the line like a truck with great facility. The coupling f is formed for the purpose of connecting the sledge with the train in the usual way, by means of a joint and pin.
The retarder when out of action, and connected with a train, is attached to the last carriage as shown at l; the sledge then rides above the rails, and is suspended by the spring pieces b b; but should an accident happen which would stop the train, one of the conductors immediately detaches the retarder, and runs back with it, and places it 500 or 600 yards behind the broken down train; then should the engineer of the following train not observe the train before him, and stop his engine, the engine would run into the retarder, and would become a sledge, and the driving wheels, if not stopped by the great resistance which would now be opposed to them, would skid round in the retarder and would have no power to move forwards. No violent concussion would take place, but the engine would slide along a certain distance in the retarder, when the train would be brought to a stand-still. A hanging frame k must be formed from the engine frame, and the buffers usually placed upon the head board must be transferred to the lower frames, or other buffers I be placed there.
In the case of a swift train overtaking another train in a fog, or at night, the swift engine would run into the retarder, and the same effect upon the engine and train would be produced as before stated; viz. that it would be brought to a stand; and the only effect produced to the slow train behind which the retarder was travelling, would be, that it would be torn away from its fastenings; for the purpose therefore of a.case of this nature it will be advisable to make the fastenings such that it may be torn away without the last carriage being subjected to any violent shock; with this view the pin at f may be of oak or hard wood, strong enough to drag the retarder. but sufficiently weak to give way in the case mentioned.
AN APPARATUS TO PREVENT COLLISION BETWEEN TRAINS ON RAILWAYS