40 RAILWAY CONSTRUCTION. 



to the depth of an inch or an inch and a half, are always distinct, 

 and there is no difficulty in defining the corresponding track. 



The result of a large number of measurements gave an 

 average width of about 4 feet 11 inches from centre to centre of 

 the wheel-tracks, a curious coincidence with the gauge of our own 

 road vehicles at the beginning of the railway era. Whether our 

 selection of the railway gauge of 4 feet 8 inches has been the 

 result of study, imitation, or caprice, we certainly have the silent 

 testimony of these old deep-worn stones to prove that two 

 thousand years ago the chariots of Pompeii were of very similar 

 gauge to our own of modern times. 



Narrow-gauge railways, of gauges varying from 1 foot 

 10 inches on the Festiniog Railway, to 3 feet, 3 feet 3 inches 

 (metre), and 3 feet 6 inches, have been made in several places 

 both at home and abroad. Generally speaking, they have been 

 constructed as subsidiary or auxiliary lines in thinly populated 

 districts, with a view to afford some railway accommodation 

 where it was considered that lines of the standard gauge would 

 not pay. In some instances abroad long lines of narrow gauge 

 3 feet and 3 feet 6 inches have been constructed as main trunk 

 lines in newly opened out districts. Some of these have since 

 been altered to a wider gauge as the traffic developed, and 

 experience proved that the narrow wiclth of the vehicles was 

 unsuitable for quick transit, or convenience in the accommoda- 

 tion of passengers and goods. 



The object in making a line to a narrow gauge is doubtless 

 to save cost in the original construction ; but when a scheme for 

 an altered gauge is put forward, it will be well to consider what 

 amount of advantage or saving would be effected by deviating 

 from the standard gauge. 



If there be almost a certainty that such proposed line will 

 always remain isolated from all other existing railways of the 

 standard gauge, then perhaps the selection of gauge may be one 

 of minor importance, and there remains but the question whether 

 the description of traffic, and the weights to be carried, can be 

 worked to any greater advantage, or more economically, by 

 deviating from the standard gauge. 



If, however, there be a fair probability that such proposed 

 line may at some future time become part of an already 

 established railway system, it would appear to be more prudent 

 to make the line to the standard gauge, and effect economies 



