RAILWAY CONSTRUCTION. 351 



arrangement which promises greater facilities for dealing with 

 the ever-increasing demands made on their carrying powers. 



Passenger and goods traffic are so dissimilar in their require- 

 ments that when both of them are steadily increasing it becomes 

 difficult, if not impossible, to work the two classes over an 

 ordinary double line. In some cases much assistance has been 

 obtained by shortening the lengths of the working sections and 

 introducing intermediate electric telegraph block stations between 

 the ordinary stations. Long refuge-sidings have also been intro- 

 duced at many of the signal-cabins or stations, into which goods 

 trains can be shunted out of the way to allow fast passenger 

 trains to pass through without stopping. Up to a certain extent 

 this arrangement works fairly well, but where there is a very 

 frequent service of fast and slow passenger trains, combined with 

 a heavy and constant service of goods and mineral trains, the 

 two lines of way are practically incapable of accommodating 

 such a number of mixed trains without causing serious detentions. 

 The goods trains must shunt out of the way some time before a 

 passenger train , is due, and this frequent shunting into sidings 

 results in hours of delay in the transit of the goods and cattle 

 traffic ; and when one of such trains is allowed to proceed again 

 on its way up to another station, dove-tailed as it may be between 

 two fast passenger trains, there is always the tendency to run at 

 a much higher rate of speed than is prudent for the class of 

 rolling-stock of which the goods train is composed. To over- 

 come this difficulty some railways have introduced additional UP 

 and DOWN lines on the busiest part of their system, making four 

 lines of way in all, two of these being reserved for the fast 

 passenger and through trains, and the other two for slow trains, 

 goods, and mineral trains. This arrangement of the four lines 

 has afforded great relief to the traffic of all kinds, and has enabled 

 the service to be worked with much greater facility and punctu- 

 ality. The goods trains being restricted to their own separate 

 lines, can proceed regularly in their order, at their uniform 

 working speed, without having to resort to the spasmodic fast 

 running too often expected from them when passing over some 

 parts of an ordinary double line. Doubtless this four-line system, 

 or rather the principle of laying down two additional lines of 

 way, will go on extending, and will be accelerated in its accom- 

 plishment by the growing demand for still higher speed of our 

 fast passenger trains, and still longer distances to be traversed 



