LIGHN RAILWAYS FOR NEW ZEALAND.

Wairarapa Age, Volume XXXI, Issue 9025, 11 January 1908, Page 5

LIGHN RAILWAYS FOR NEW ZEALAND.

By Predk. Black, A*M. Inst. E.E. (Published By Special Arrangement). ll. —(Concluded). A leading railway engineer has made the statement that in no country ought there to be any other classes of lines than the 4ft Bsin> gauge of medium to heavy type, and the 2ft 6in gauge of .Jight type. At the present stage of the .world's de- { velopment this is a counsel of perfeci tion, but it contains endorsement of the sound principal that a country's railway expenditure should not be all on the standard type—and it may be added not even when that standard is the 3ft 6in gauge, as in New Zealand. The narrow gauge, light line is as necessary an auxiliary to our railways as it is to those of other countries. In the great majority of instances the gauge of a light railway is less than that of the standard lines of the country, in which the undertaking is situated, but the fact of it being on the larger gauge does not make it any the less a light line. In level country the choice of standard instead of a narrow gauge, does not very seriously increase the cost of a line, as it is the amount of earthworks and road bed formation] necessary in a hilly oi* mountainous district that is the principal factor in determining expenditure. Not many light lines, however, of 4ft BJin gauge have been or will be constructed, as that gauge is too wide to permit of the lightest track designs. For New Zealand service 3ft 6in light railways while quite feasible as ei gineering propositions, will be built probably only in those cases where re-constuction into standard lines in a few years' time is intended. Unless such lines are laid out with easier curves than are usual for li<?ht railways, main line rolling stock cannot run over them, and to get the easier curves is often a very expensive matter in hilly country. Low capital cost being the main consideration in this work its influence may be expected to extend to the question of gauge in all cases but those just mentioned. For many reasons it is desirable that the same gauge should be adopted throughout the country for all light lines (other than 3ft Gin ones) carrying on public business. A common gauge for these systems means cheaper rolling stock, because makers can standardise patterns and cheaper repairs, because standard spare parts can be stocked; it fur!her means the possibility of sale or hire of plant from line to line and it will enable neighbouring systems to some day link up as the districts develop. Electric traction will be largely used and its interest particularly require a common gauge, as motor equipments become very costly when built in small numbers for gauges seldom used. Taking all points into consideration, the 2ft 6in gauge is, in my opinion, the one that should be chosen for general acceptance; it gives a satisfactory freight-carrying capacity—on the Leek light railway (England) which is of this gauge, cars 40ft long and 6ft 9in internal width are used, and run up to thirty miles an hour —and permits of convenient roomy passenger cars that will operate without continual oscillation. The most important advantage of nil, perhaps, is that it does not cramp the design of electric traction motors to that degree at which either power'or reliability and efficieny have to be sacrificed. It is as much the correct gauge for those lines, where owing to sparse traffic steam locos should be employed, as for electrical undertakings; sooner or later with the development of the district concerned, electricity will claim consideration, and then the question of space available for motors will be of great importance. It is probable that in most parts of New Zealand where light railways will be built, a better location than on the existing main roadr cannot be obtaired. Certainly on the chain wide roads there is abundant room, and to spare, for a track with passing places and a pole line for over-head work, without restricting the general highway use. The Belgian light railways are to a very large extent built on the sides of roads, and the two lines now projected in this country will, if built, be road lines. Possibly it is for this reason that the latter have so far been called tramways —a term which is rather apt to,convey the impression of a track with gro ived rails sunk in the roadway and a paved or macadamised surface uniform with the rest of the road. Actually, the only construction that is possible in these cases is v an exposed rail of ordinary Vignoles section, with ballasting on the read, instead of under it, the road surface being first brought to formation level. Owing to the grades on such roads as are common in this country, it is a foregone conclusion that apart from any other consideration, electric traction will have to be employed in the majority of road-located light lines. Few people will deny that great benefit will be derived from the establishment of these cheap yet efficient transport systems, or that many a district now longing and hoping for a standard branch railway, would gain more in the long run by building for itself a light Mine than by continuing to maintain,expensive roads and pay heavy cartage rates for an unknown number of years. Private enterprise in matters of public utility is allowed few opportunities in New Zealand, but it is surely desirable that it should not only be permitted, but welcomed, under proper conditions, for fostering light railway development in every case where the local bodies are unable or unwilling to assume the responsibility. The Government, with several years of standard railway construction before it, cannot be expscted to do much, if anything, towards building the lines, but it can easily render abortive other psople's efforts, by imposing such restrictions and "safeguards" that neither Councils nor investors will be able to embark upon the work. It would be a thousand pities if the tie-up of the water powers were to be paralleled by a tie-up of light railway enterprise.