main lines will have to be reduced to the smallest possible number.

It would be difficult to form an opinion as to how far passenger traffic will go on expanding, but if it continues to increase at the same rate as at present, some railways may find it expedient, and even absolutely necessary, to construct new lines altogether separate and apart from the existing routes, and for the sole use of their fast through traffic. As roadside or intermediate traffic would not form any part of the scheme, such lines could be laid out so as to keep away from the populous districts, where property would be costly, and pass instead through those parts of the open country where the most direct course and easiest gradients could be obtained. Stations would only be required at the very large and important places, and at long distances from each other. Lines of this description, reserved for through traffic only, taken alone, might not pay, but taken in conjunction with the existing lines, of which they would form a part, they might prove to be the best solution of the problem of dealing with a crowded train service, the remunerative earnings of which, placed together, might yield a rich return over the entire system. A project for a separate through line might at first appear a little startling, but we have well-known precedents in the vast expenditure already incurred in the constructing of enormous viaducts and connecting lines to avoid long detours on certain through routes. The widening out of an ordinary double line into a four-line road was at first considered as a rather venturesome departure; and it must always be costly because, in addition to the earthworks and permanent way, there is the doubling of all the over and under bridges and waterways, besides the great and expensive alterations at stations. Practically it is almost like making a second railway, and yet the constant extension of the principle is an admission that the working results have proved satisfactory, in spite of the large outlay. A little later the question will force itself more prominently into notice, whether the four-line track or the separate fast through traffic lines, will best answer the purpose. The former possesses certain advantages, but the latter would give more freedom for high-speed running.

Engineers have brought railways to their present stage of perfection, and the public will expect them to devise and carry out still further improvements as the march of development

moves onward. It is a simple matter to arrange the traffic on a railway when all the works and appliances are appropriate for the service to be performed; but the advances which are made follow one another so rapidly as to necessitate constant study and organization to effect the structural alterations and additions requisite to maintain an up-to-date standard of efficiency. The traffic manager on a railway receives his instructions from the directors or controllers of the company as to the working out of the train service, rates, charges, and other items of his department, but the engineer has to stand alone, and his technical knowledge and professional skill must enable him not only to design and construct works suitable in character, extent, and strength to the duty for which they are intended, but also to decide when structures are no longer capable of properly sustaining the increasing loads brought upon them, and must be taken down and replaced with others of a stronger description. For this reason the engineer must carefully consider every circumstance and local feature which may influence the design to be prepared; he must thoroughly investigate the nature of the ground for foundations, as the description when ascertained will frequently determine the class of work to be erected, whether in viaducts, bridges, or buildings; and in his selection of materials and calculations for strength, he must allow ample margin to meet further increased weights, as well as for natural deterioration.

He should, indeed, go a little further, and as his perceptive ability and training will always enable him the more readily to foreshadow the direction in which improvements or changes are tending, he should study out and be prepared with his schemes to meet the new departures as the requirements gradually arise.

Strength and efficiency are the leading points which must be always kept in view, and the engineer must never forget that he is solely responsible for the safety of the line and works, and of the public passing over the same.

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INDEX