TRANSACTIONS OP SECTION J. 495 



the previously-calculated value of 2a + 3b in order to get the 

 required 2a + 4b -\- 3c : this is then multiplied by c. Similarly 

 in the next we add on c + 3d to the previously -calculated 

 2a + 46 + 3c, and multiply the result by d. The whole thing 

 can be done in a very short time, and is a great saving on any 

 methods of calculation. 



The following are the results of the wall worked out : — 



Distance 

 from Top of Wall. 



Ofeet. 



5 „ 



10 „ 



15 „ 



20 „ 



25 „ 



30 „ 



35 „ 



40 „ 



45 „ 



50 „ 



Plate XVI. shows the necessary construction to obtain the 

 last seven widths. 



6. 071 Railway Gauge as a Factor in the Profitable Working 

 of Locomotive Bailways. 



By E. DoBSON, M.Inst.C.E. 



The subject of this paper is an inquiry into the extent to which 

 the gauge of a railway affects its constructive cost, its workiu<»- 

 expenses, and its capacity for traffic. 



For obvious reasons, no notice will be taken of lines worked 

 by electricity or by rope traction ; nor is it thought necessary 

 to allude to gauges narrower than 3ft. 6in., or wider than 

 5ft. 6in., such extreme gauges being recognised as only suitable 

 for special conditions of traffic. Practically, however, the in- 

 quiry will be confined to the consideration of three gau.^es 

 only — viz., 3ft. 6in., 4ft. 8-|in., and 5ft. 3in. — which, for the 

 purpose of this paper, will be called respectively narrow, 

 standard, and broad gauges. The 5ft. Gin. gauge may be dis- 

 missed from the inquiry simply with the remark that it em- 

 braces the advantages of the oft. 3in. gauge, but with additional 

 weight of axles, extra length of sleepers, and greater distance 

 from switch-i-ail to crossing-point, without sufficient couipcn- 



