RUNNING TRAINS ON SINGLETRACK RAILROADS.

Globe, Volume XX, Issue 1382, 20 July 1878, Page 3

RUNNING TRAINS ON SINGLETRACK RAILROADS.

[From the “ Chicago Railway Review.] An improvement of considerable practical value has been made by Mr C. Hodgson, the manager of Messrs Saxby and Farmer’s Railway Signal Works at Kilburn, England. It consists of a mechanical combination of the block and interlocking systems, eliminating the last atom of the element of human fallibility which remained for human ingenuity to dislodge. The apparatus by which this is accomplished consists of a frame, containing in its lower portion the usual levers for working the points and outdoor signals, and in its upper a series of train telegraph instruments for signalling and recording. The main signals, which are made visible on the telegraph instruments to each operator, are “line clear,” and “line blocked.” Now, before one signalman can telegraph back to another, who has telegraphed to him that a train is coming, that the line is clear for it, the points and outdoor sign ds must be in the proper position for that train to pass. Until they are so the telegraph instrument is locked, and the signal “ line clear,” cannot be made. Similarly, when “ lino clear ” has been telegraphed, the points cannot be moved or the signals altered for shunting to go on upon the clear road until “ Line blocked ” has been telegraphed to the station on either or both sides of the signalman. The operation of sending the “Line blocked ” message—and this alone —frees the levers by which the points and signals required for shunting can be operated. Again, assuming a train to be standing in a statino, and ready to proceed on its way, the signalman cannot give the driver the out-door signal for the train to start until he has signalled “ Train on line” to the station in advance. The sending of this telegraphic signal alone releases the lever, and enables it to be worked to give the starting signal so that a train cannot go on its way unannounced unless the driver proceeds in utter disregard of the signal against him. But this is not all; the signalman cannot give the out door starting signal until the man at the station in advance has telegraphed back “ Line clear ” in reply to the signal “ Train on line.” In sending the “ Line clear ” message, the man at the station in advance electrically unlocks the telegraph instrument, and through this the starting signal at the station from which the train is about to start, and so the train cannot proceed—except in defiance of signals—without the permission of the man at the station in advance of it. Thus provision for a train to enter a block section cannot be given without the consent and concurrent action of the signalmen at bo! h ends of that section. Nor is the train less protected at the rear than in the front, inasmuch as until the signalman who has just started a train puis his starting lover, anci, consequently, the starting signal, back to “ Danger,” he cannot telegraph the “ Line clear ” for the next train to the station below him, for his telegraph instrument remains mechanically locked. Further, when the starting signal has been put back to “ Danger,” it cannot be given again without the consent ot the man at the station in advance. It is a very important feature in Mr Hodgson’s invention that its adoption does not mean a heavy outlay to railway companies. Neither new locking apparatus, nor telegraph instruments, are necessarily involved ; t,hose at present in use will answer all purposes when the two are mechanically connected under Mr Hodgson’s patt n,t. The apparatus has been officially inspected by Colonel Yolland, and he has reported to the Board of Trade his unqualified approval of the system.