TEANSACTIONS OF SECTION J. 471 



of fuel in the locomotives per indicated horse-power is given at 

 5-2531b. 



The author is able to speak w^ith some authority on the use 

 of steep grades on mountain railways, as he was associated with 

 Mr. Carruthers when the application of the principle to the 

 Puerto Cabello and Valencia railway was under discussion, 

 and then made several visits of inspection and research to 

 Blankenburg, and saw the practical working of the Abt system 

 under favourable and unfavourable conditions, and he made 

 further investigations before recommending the change of 

 location on the New Zealand Midland railway at Arthur's 

 Pass, and also with the view of drawing up a report on the 

 same question in 1888, as Joint Consulting Engineer in London 

 to the New Zealand Government. The changes made by the 

 author in the location of the New Zealand Midland Eailway 

 Company's line at Arthur's Pass have been criticized by many 

 in the colony ; and, as the question is of some local interest, 

 a few leading particulars and reasons which have induced the 

 author to advise the change of location from the summit tunnel 

 of three miles and a quarter in length to an mcline with grades 

 of 1 in 15 may be of some interest. Most of the following 

 particulars were included in the report to the New Zealand 

 Government. 



To form a comparison between the Abt incline and the 

 tunnel line as originally surveyed, it is necessary not only to 

 take into consideration the tunnel and the incline, but also the 

 section of railway affected by the substitution of the incline 

 for the tunnel. The length of line on the original survey con- 

 stituting the affected section is about 21 miles 16 chains, made 

 up of the tunnel, 3 miles 16-5 chains, 14 miles 18 chains of 1-in- 

 50 grade, 6 miles 16-3 chains of lighter grades, including the 

 level bridge over the Teremakau Eiver, to the West Coast 

 termination of the survey made for the Government by 

 Mr. Napier-Bell, now an esteemed member of the author's 

 personal staff. Going westward the line has a down-grade 

 through ^the tunnel of 1 in 44 ; on leaving the tunnel it is 

 located, with a grade of 1 in 50, on the hillside overlooking 

 the valley of the Eolleston Creek, the Otira and Teremakau 

 Rivers ; there are two short tunnels, as well as the longer one 

 through the summit, and several very high and costly viaducts, 

 crossing deep gullies formed by the tributary streams of these 

 rivers. The line for about fourteen miles is on the sidling 

 ground of the hills, and in many places shows a heavy section 

 for construction, and, moreover, crosses many shingle-slides, 

 some of them of great magnitude, which would require special 

 works to render the line stable, and in some cases the solution 

 of the; difficulty would be tunnelling behind these ever-shifting 

 masses of loose rock. If the line had been constructed as sur- 



