When, in 1874, I started on the construction of my experimental railway, the more notable narrow-gauge lines in our own country were those of 18 in. at Crewe, Woolwich, Chatham, and Aldershot—the latter a sad failure and the admirable 23½ in. from Portmadoc to the Festiniog Slate Quarries. The Festiniog Railway, which owed its success as a locomotive-worked line to the persistent energy and ability of the late Mr. Charles Spooner, opened the eyes of the transport-interested world to the extraordinary capacity of a very narrow gauge. But here the marvel lies in the manner in which the work was adapted to the gauge, not in the suitability of the gauge to the work. No one but an enthusiast would dare to contend that a two-foot gauge was the ideal width for a line employing twenty-ton locomotives and hauling about 100,000 passengers and some 150,000 tons of minerals and goods per annum. If this development could have been foreseen, the selected gauge would doubtless have been wider. Such a traffic, however, is quite outside the scope of this pamphlet, the logic of which is directed to shewing how a much smaller annual tonnage than has been hitherto deemed worthy of a railway may be profitably thus conveyed.

An 18 in. line, such as one of those above referred to, would, if of not more than three or four miles in length and tolerably level, be capable of transporting, with one locomotive, 60,000 tons of minerals annually, reckoning the traffic as in one direction only. There are, however, up and down the country, a number of cases where a traffic of from 5,000 to 10,000 tons is annually hauled between two fixed points over the public highways by a single employer. Such cases may be classified as large mansions, public institutions, mines, quarries, &c. Now it is clear that, unless there is a prospect of large increase in the traffic, it would be absurd to employ for a maximum of 10,000 tons a railway equal to 60,000 tons, and so the question arises:—What is the smallest and therefore the cheapest railway capable of being practically and advantageously worked? This is the question to which I venture to think I can give a reliable answer.

In the year 1874, after various preliminary trials, I determined to construct a line of 15 in. gauge, as the smallest width possessing the necessary stability for practical use, although I once laid down one of 9 in. gauge for my younger brothers, which proved by no means deficient in carrying power.

The stability of this 9 in. line was perfect enough so long as persons did not attempt to ride on the ends and edges of the carriages and wagons, but man being an article of approximately standard size, it is clear there must be a minimum gauge which will be stable enough to be independent of such liberties.

Rolling stock properly proportioned to a 15 in. gauge seems the smallest that will thoroughly insure safety in this respect, and indeed in France the late M. DÉcauville, who did so much to develop lines of this class, arrived at nearly similar conclusions in adopting a minimum width of 16 in.

It must not, of course, be understood that gauges of such small proportions are to be advocated except where the traffic is unlikely to increase beyond their capacity, and where the material to be moved can conveniently be loaded in moderate sized wagons.Feeling, however, convinced of the eventual recognition of the utility of lines of minimum gauge, I took some pains to become acquainted with what had been already achieved in this direction, with the result that, excepting only the Festiniog railway, where every detail was most ably worked out by the late Mr. Spooner, I found generally both road and rolling-stock constructed as mere imitations of those of the standard gauge, and showing a want of apprehension of the totally different conditions to be satisfied. To endeavour to solve the various problems involved in the successful design of engines, carriages, wagons, and roadway for a minimum gauge is, therefore, the main object of my little railway. The chief ends in view are the application of such lines to agricultural or commercial purposes on large estates, or where quarries, brick yards, and other industrial establishments need better connection with the pier or railway station from which their productions are forwarded. An excellent example of such a line is now to be found in the one I have constructed at Eaton Hall, particulars of which are given in Section IV. There were also problems relating to adhesion and friction, particularly from the narrow-gauge point of view, which I was desirous of solving, some remarks on which will be found in Section VIII.