July 13, 1883. | 



SCIENCE. 



33 



switches on the cross- 

 ing roads, so that cross- 

 ing trains running 

 against signals will be 

 turned into a side-track, 

 and cannot, therefore, 

 cross or foul the main 

 line. There are, in all, 

 fifteen switches handled 

 and controlled, a n d 

 three other switches 

 not handled (owing to 

 the infrequent use, or 

 being required only for 

 hand-drilling), which 

 are also perfectly con- 

 trolled. Twelve facing 

 point locks and seven- 

 teen signals are em- 

 ployed, some of thera 

 2,150 feet from the sig- 

 nal-tov.er. To operate 

 the above, twenty-eight 

 interlocking levers are 

 used, with two spare 

 levers in the frame for 

 future improvements. 

 At ibis writing, the 

 apparatus at Union 

 Junction has been in 

 use over one year with 

 perfect success, and it 

 will probably repaj' an}- 

 railroad manager to 

 visit jt, and study its 

 workings. 



In arranging a yard 

 on the interlocking sys- 

 tem, it is important to 

 concentrate the switch- 

 es so that the}- can be 

 woiked by one man 

 from one machine, 

 where as many as fitly 

 levers operating 

 switches and signals 

 can be conveniently ar- 

 ranged. I'rovided that 

 the yard is well laid 

 out, it is possible not 

 only to gain greater 

 safety and security in 

 switching and drilling, 

 but a saving in time 

 and labor is etfected, 

 as one man who is 

 always on the same 

 spot can perfonn the 



5 \4 



5 ■ll 



work of several men scattered about a yard, 

 and having continually to move from one 

 spot to another. The levers should be placed 

 in a house constructed so as to shelter the 

 siiinalman fron\ the weather, and enable him 

 to have a good view of the whole yard ; and 

 the latter object is generally best attained by 

 placing him at some distance above the ground- 

 level, so that bis view is not obstructed by 

 l)assing engines and cars. 



The levers, which resemble the reverse 

 lever of a locomotive, are mounted close to- 

 gether in a line, and a name or number plate 

 on each lever shows its use and purpose ; and, 



% 



to further distinguish the levers, all those 

 operating switches may be painted one color, 

 locking levers another color, and so on. 

 Each hand-lever carries a spring-catch, which 

 secures the lever at either end of the stroke ; 

 and the detent, forced down by the spring, 

 and pulled up by the action of the signalman's 

 hand in grasping the handle-end of the lever 

 and its catch, instead of engaging n\ a notched 

 rack, as on a locomotive, slides in a curved 

 slot in a pivoted bar. This bar, or 'rocker,' 

 is therefore moved about its pivot by the verj' 

 action of the signalman grasping the lever. 

 Interlocking virtually consists of mechanism 

 attached to this pivoted bar, which renders 

 it immovable under certain circumstances. 

 These controlling circumstances are the posi- 



