USES OF THE TELEGRAPH TO RAILWAYS. 



cause, give immediate notice to the preceding and succeeding sta- 

 tions, so as to prevent a collision by a following train overtaking 

 that which is accidentally stopped, or if necessary he can call for an 

 engine to carry on the train, or any other aid that may be required. 



247. Notices of the passing, starting, and arrival of trains are 

 however transmitted from station to station, quite independent of 

 any accidents that may arise, so that all the station-masters, so 

 far as relates to the movement upon the line, are endowed with a 

 sort of omnipresence ; so conscious are they of the possession of 

 this power and its value, that their language is that of persons 

 who actually see what is going on at vast distances from them. 

 Thus, as Mr. Walker observes, they are in the common habit of 

 saying " I just saw the train pass such or such a station," fifty 

 miles distant perhaps, when in reality all he saw was the deflec- 

 tion of the needle of their telegraph. 



" If trains are late, the cause is known ; if they are in distress, 

 help is soon at hand : if they are heavy, and progress but slowly, 

 they ask and have more locomotive power either sent to them 

 or prepared against their arrival ; if there is anything unusual on 

 the line they are forewarned of it, and so forearmed ; if overdue, 

 the old plan of sending an engine to look after them has become 

 obsolete a few deflections of the needle obtain all the information 

 that is required." * 



The utility of special trains is well known. News of the utmost 

 importance, or a government courier bearing . dispatches of the 

 greatest urgency arrives at one of our ports and demands a train 

 instantly to convey him to London. Now in such cases it does 

 not often happen that a disposable engine is found at the station 

 where the demand is presented ; but the telegraph sends a dis- 

 patch along the line, calling one from the nearest station at 

 which one can be found, and when the engine has been 

 obtained the special cannot start with safety unless the line is 

 cleared for it. 



The telegraph again interposes its aid, and sends a notice along 

 the line of the moment of starting, from which, combined with 

 the known speed of the train, the exact moment when it will pass 

 every station upon the line is known, and of course the line is 

 cleared for it, and all danger of collision removed. How frequent 

 are the occasions for appealing to the telegraph for this aid 

 without which special trains would not only be less rapid, but 

 infinitely less safe, as well for themselves as others, may be seen 

 by^reference to the analysis of dispatches we have given above, 

 from which it appears that in three months, upon the South- 



* Walker, p. 84. 



79 



