}865.] Tyler on Circulation and Communication on Railways. 577 



But there are other reasons why it would be impossible, without 

 extensive alterations, to carry out such a system generally on British 

 railways. The ordinary width of the carriages is 7' 4", projecting 

 1' 2", and they are constructed on many lines up to widths of 8 or 

 even 9 feet, projecting 1' 6" or 2' on each side of the rail. The 

 distance between the two lines of rails is 4' 85" or 5 feet on some of 

 the older lines, and 6 feet on modern lines ; and the maximum 

 distance between the rails and the side-works varies on different lines. 

 To take an instance, the minimum distance between the outer rails 

 and the side-walls on the London and North- Western Bailway is in 

 the following tunnels : — 



Upside. Downside. 



Ft. In. Ft. In. 

 Beechwood Tunnel (near Coventry) ... 2 3 2 3 J 



Walford Tunnel 2 3 3 4J 



Primrose Hill Tunnel 28 25 



But allowing 2' 4" in the clear as the minimum space in which a 

 conductor should be allowed to pass between the outside of a carriage 

 and a standing work at the side of the line, there would then be 

 required, for a carriage 7' 4" wide, 3' 6" ; for one 8' wide, 3' 10" ; 

 and for one 9 feet wide, 4' 4", between the outer rail and such stand- 

 ing work. And the dimensions above given are, as will be seen, 

 quite insufficient to provide such spaces, there being only nine inches 

 between the up sides of the two former tunnels and those of a 

 carriage 8 feet wide, and only 1' 3" in the case of a carriage 7' 4" 

 wide, to allow of the passage of a guard. 



The Begulations of the Bailway Clearing House contain a very 

 good guide to the minimum dimensions of the works, in the table 

 showing the maximum dimensions of a carriage or wagon load which 

 will travel safely over the different lines in the country. It will be 

 useful here to extract the particulars for a few of the principal 

 Bailways : — 



Caledonian and Branches 



Except Portpatrick 



Great Northern and Branches 



Great Western : — 



Broad Gauge 



Narrow or Mixed Gauge 



Birkenhead 



Coleford, Monmouth, Usk and Pontypool . . 1 



Leominster and Kingston J 



Much Wenlock and Severn Junction . . . 

 Newport, Abergavenny and Hereford . . . 

 Oxford, Worcester and Wolverhampton . . .1 



Severn Valley J 



Shrewsbury and Birmingham 1 



Shrewsbury and Chester ., ) 



Shrewsbury and Hereford 



Width of 

 Load. 



Height in 

 Centre. 



Ft. In. 



10 

 9 

 9 3 



Ft. In. 

 14 



12 11 



13 9 



11 6 

 9 2 



8 9 



15 

 15 

 12 9 



8 6 



13 



9 

 9 



13 

 13 



9 



13 



7 8 



13 4 



9 



'13 



Height at 

 Side. 



Ft. In. 



10 9 



10 9 



10 3 



11 8 



11 8 



12 



11 



11 6 



11 



11 6 



11 8 



11 « 



