E.—6

1875. NEW ZEALAND.

REPORTS ON BRANCH RAILWAYS (CORRESPONDENCE RELATING THERETO).

1. TOKOMAIEIEO BEANCH EAILWAT. 2. G-EEEN ISLAND BEANCH EAILWAT. 3. TAIEEI PLAINS TO OLTEAM EAILWAT.

Presented to both Souses of the General Assembly by Command of His Excellency.

I.—REPORT ON THE TOKOMAIRIRO BRANCH RAILWAY. No. 1. Mr. W. N. Blaie, District Engineer, to the Engineeb-in-Chief. Sic,— Public Works Office, Dunedin, 27th November, 1874. In accordance with the instructions conveyed by telegram on the 25th August, I have the honor to submit the following report on a Branch Railway to connect the Tokomairiro Coal Meld with the Dunedin and Clutha line. On the 27th August, I submitted an interim report on the subject. Since that date I have made a reconnaisance survey of the route, the resulb of which is embodied in the accompanying plan and the following report. You will however find, by comparison, that the opinions expressed in the interim report are not much modified by the information subsequently obtained. The plan shows in distinctive colours the various mining properties now operated on, and the position of the mines that have already been opened out. The line which I have selected leaves the Clutha Railway at the Milton Station, and proceeding eastward skirts the northern bank of the Tokomairiro for four miles, then turns off at right angles for a mile further, passing through the " Mackay " property to the Bruce Company's mine—the total length of the branch being exactly five miles. My interim report only provided for the construction of the line to the nearest boundary of the Coal Reserve; but I now find that no part of the field would be accommodated by a terminus there, so I have shown it extended to the furthest away mine. It might, however, be found advantageous to terminate the branch at some central point, say near 4/40 in section 31, Block VI., Akatore District, leaving the proprietors of the various mines to connect their tramways with it. With the exception of 10 or 15 chains near 2/0 the whole of the route above described is remarkably favourable to railway construction. More than half the distance will be surface forming, and the earthwork on the remainder of the lightest possible description. There are no streams of any magnitude to cross, and the small watercourses are not numerous. The rough ground at 2/0 consists of a very steep clay terrace that runs out into the river bed. There is only about 4 chains where there is no room for the line between the terrace and the river, but the whole bight is subject to heavy floods, so it would be necessary to keep sufficiently high to clear them, and also to protect the bank in some way. If on taking a section it is found that the difficulties above referred to are of a serious nature, another line could be got in the direction dotted on the plan ; but, in addition to the disadvantage of two river crossings, I fear this will be found as much subject to floods as the other. With the view of shortening the branch, two other routes have been proposed between 3/0 and the terminus —one leaving about that point and the other about 3/40, and proceeding in direct courses across the intervening ridge to the Bruce Company's Mine. The first of these would save about a mile in distance, but it would have a tunnel 20 chains long. The second would save about 25 chains, with a tunnel of 4or 5 chains. In both cases the earthworks would be very heavy, and the gradients from lin3sto 1 in 50. Neither of those lines, whether considered in point of cost, superiority of gradients, or accommodation afforded, can bear comparison to the longer one, which is shown on the plan. Without a section I cannot give an accurate estimate of the cost of the Tokomairiro Branch Rail--I—E. 6.