Although the drawing shows only the form of boxes used for the conveyance of coals, yet it will readily occur that the form can be varied to suit the carriage of any kind of articles; the framework or body of the carriage being raised above the wheels, the breadth can be extended to any width which the distance between the railways [i.e. between the up and down lines of road] will admit (p. 75).
Such was the state of matters when, in the year 1833, Mr. Brunel was appointed Engineer of the Great Western Railway. With the view of leaving the question of gauge open for future consideration, he procured the omission in the Great Western Act of a clause defining it. He came to the conclusion that it would be desirable to adopt a wider gauge, and he recommended this measure to the Directors in a report dated October 1835.[47]
In October 1836 a Royal Commission, consisting of Mr. Drummond, Under-Secretary for Ireland, Mr. R. Griffith, Colonel (now Field-Marshal) Sir John Burgoyne, R.E., and Professor Barlow, of Woolwich, was appointed to report on the establishment of railways in Ireland. They considered carefully the question of gauge, and their arguments in favour of an increase in the gauge were afterwards stated by Mr. Brunel to be identical with his own.
They drew attention to the advantage of large wheels, the use of which would be facilitated by a wider gauge; and they thought it a matter of importance to be able to place the bodies of the carriages between the wheels, instead of over them.
It was the width of the carriages, and not the distance between the rails, that determined the general dimensions, and therefore the cost, of the works of a railway. Mr. Brunel saw many advantages to be gained by an increase in the gauge, even while retaining the existing dimensions of carriages; and he thought it unwise at the commencement of a work of such magnitude as the Great Western Railway to retain a limit the inconvenience of which had already become apparent.
He says, in his evidence before the Gauge Commission:
Looking to the speed which I contemplated would be adopted on railways, and the masses to be moved, it seemed to me that the whole machine was too small for the work to be done, and that it required that the parts should be on a scale more commensurate with the mass and the velocity to be attained. (Q. 3924.)
The width between the rails being the fundamental dimension of ‘the whole machine,’ on which its entire development must depend, Mr. Brunel proposed to begin by the enlargement of this dimension, and recommended that on the Great Western Railway the gauge should be seven feet. He considered that the whole of the parts of the railway and of its rolling stock would be susceptible of continual, though gradual improvement, and that it was highly advisable to remove, in the outset, a great obstacle in the way of this progress.
He did not in the first instance propose any important change in the details as consequent on the wider gauge; and in regard to one of the principal points, the diameter of the wheels, he said:—
I am not by any means prepared at present to recommend any particular size of wheel, or even any great increase of the present dimensions. I believe they will be materially increased; but my great object would be in every possible way to render each part capable of improvement, and to remove what appears an obstacle to any great progress in such a very important point as the diameter of the wheels, upon which the resistance, which governs the cost of transport and the speed that may be obtained, so materially depends. (Report in Appendix I. p. 532.)