1870.] Engineering — Civil and Mechanical. 265 



6. ENGINEERING— CIVIL AND MECHANICAL. 



Light Railways. — The great question of the day amongst engi- 

 neers, at the present time, is the construction of light, or narrow- 

 gauge railways. The enormous expense which has attended the 

 laying-down of existing lines upon what is styled the "standard" 

 gauge, and then comparative unremunerativeness, have naturally 

 led to the consideration of how the existing want of increased 

 facilities of communication can best be supplied so as to recommend 

 new projects for railway extension to the confidence of capitalists 

 and the public generally. The subject has also obtained increased 

 prominence in consequence of the arrival of a Russian Commission 

 to investigate the means of communication in this country, and who, 

 together with many other foreigners of distinction, and leading 

 English engineers and others, paid a visit last February to the little 

 Festiniog Railway in North Wales. As this line has the narrowest 

 gauge of any existing railway worked by locomotive power, some 

 description of it here may not be inappropriate. 



Festiniog Railway. — This line, which is 13 J miles in length, 

 extends from Portmadoc to the slate quarries in the neighbourhood 

 of Festiniog. It is slightly under 2 feet in width of gauge, and 

 was originally constructed for horse traction, by which power it 

 was worked until 1863, when the increased traffic necessitated the 

 employment of steam power for that purpose. The fine was 

 strengthened and improved, diminutive locomotives were con- 

 structed expressly for it, and since 1865 passenger carriages have 

 been attached to each train. The difference in level between the 

 two termini is 700 feet, and the average gradient is 1 in 92. The 

 steepest gradient on the portion now used for passengers is 1 in 79 ■ 82, 

 and the steepest on which locomotive engines are employed, 1 in 60. 

 Some of the curves are exceedingly sharp, having radii varying from 

 2 chains to 4 chains. As the line is a continuous incline from 

 Portmadoc to Festiniog, the locomotive is employed only to draw 

 the trains in one direction ; it then returns by itself, and the 

 loaded trains run by gravitation down to Portmadoc — their speed 

 being regulated by breaks. The original capital of the company 

 was 36,000^. Since that outlay was incurred the line has been 

 almost reconstructed ; workshops have been erected and rolling 

 stock manufactured out of revenue, bringing up the total cost of 

 the line to about 86,0001. The net profits have amounted to 

 upwards of 30 per cent, on the original capital, and they exceed 

 1 2J per cent, on the total outlay of the undertaking. 



New Tunnel under the Thames. — The past quarter has wit- 

 nessed the completion of a tunnel under the river Thames between 

 Tower Hill and Vine Street, Tooley Street. The noticeable feature 



