17

D.—2a

The year 1928 mentioned above was adopted because this is probably the earliest date by which the work could be completed if there is not much time lost in starting, and it is also the date when conditions on the existing line will be becoming so difficult as to be almost unworkable. On the basis of the probable traffic in 1928, it is estimated there will be a saving as the result of the grade-easement projected of £33,840 pe;r annum. This figure is based on records of the costs per engine-mile of the locomotives now working the heavy grades out of Wellington. I should mention that an adequate discussion of the matter assumes that within a reasonable time after the completion of the deviation now under discussion another deviation on an equal standard will be made cutting out the heavy grades over the Paekakariki Hill; and in fact it may be advisable to have both of these deviations completed about the same time. In addition to the saving in haulage as a result of grade-easement, there will be a further saving on account of the shortening which will ensue. There will be further the saving due to the elimination of the curvature, which on the present line, though not extremely sharp, is very extensive. Quite a number of lines of deviations have been considered, and these are narrowed down to Nos. 1 and 4—No. 1 being a line from a point about three miles beyond Ngahauranga to the vicinity of Tawa Flat, and on which there would be a tunnel 2 miles 47 chains long. If it were possible to carry the traffic of both the east and west coast lines over the double track already existing between Wellington and Lower Hutt as far as the point of divergence, then this line would undoubtedly bo the cheaper ; but the Railway Department are of the opinion that this would not be possible, and that, in addition to the deviation proper, it would be necessary to allow for a quadruplication of the line as far as the point of turn-off. This is estimated to cost £154,000. The other line which has to be considered is one which leaves the present line some distance beyond Kaiwarra and joins up with the first-described line some two miles and a half south of Tawa Flat Station. This line contains more tunnelling than the previous one, but there are two and possibly three tunnels, and therefore there would be somewhat less trouble with smoke, and for the purposes of construction there would be more points of attack. This would be an advantage in the time necessary to complete, and probably will result in the tunnelling per unit of length being less costly, though no allowance in this direction has been made in. the estimates of the summit tunnels. Both of the lines described are estimated at £940,000 to £950,000, and for all practical purposes may be taken as costing the same. Coming now to the question of the duplication of the present line;, this is estimated at £550,000 ; and, as foregoing considerations show that such duplication is an absolute necessity, it can be taken that the grade-easements due to the; deviations referred, to will involve, an added expenditure; of £400,000. The interest on £400,000 at 5 per cent, is £20,000 per annum, and, as the saving on one item alone, as indicated above, is over £30,000, there appears to be no doubt that the deviation should be made, and further that it should be started almost immediately. I should be glad if you woulel give this matter consieleration and direct whether reference to the same should be made in the forthcoming Public Works Statement. With regard to the line now existing, and on which a certain amount of traffic to serve the suburbs of Ngaio, Khandallah, and Johnsonville will be necessary, it has occurred to me that it might be possible to transfer this line, at a price to be agreed upon, to the Wellington City Council, and that the;y could utilize the formation for an extension of their electric-tram system as far as Johnson ville. This may be considered as giving away part of the traffic now dealt with by the Railway Department, and would no doubt require to be carefully considered. There is another point in connection with the deviation which should not be lost sight of, and that is, with a level double line two miles shorter than the present one, all the flat country between Tawa Flat and Plimmerton would be brought within close range of Wellington, and in fact suburban passenger-trains could be run from Plimmerton to Wellington in less time than trams now take from Mi ramar to the same place.

Approximate Co>t oi Paper. — Preparation, not given ; printing (1,275 coplnn, including plans and graphs), £215

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3-D. 2a.