Part 14 (2/2)
1. It gave the power of constructing more powerful engines, by which greater speed for pa.s.senger trains and greater tractive power for heavy goods trains were obtained.[60]
2. It gave more s.p.a.ce for the convenient arrangement and beneficial proportions of the machinery, as well as for convenient access to it. In all these points difficulties had been found on the narrow gauge; and the compulsory restriction of so important a dimension as the width between the rails has been a bar to any improvements of great magnitude or comprehensive nature.
3. It gave, even with the overhanging carriage, the facility for obtaining large wheels, and consequently diminis.h.i.+ng the axle friction without sacrifice of stability.
4. The greater width of base for the carriages to rest on gave increased steadiness and smoothness of motion, particularly at high speeds. It was the impulse given by the increase of speed and comfort obtained without difficulty on the broad gauge, which had led to the chief improvements introduced in railway travelling.
5. Greater safety was secured, particularly at high speed, from the greater stability of position due to the wider base, producing increased steadiness and diminis.h.i.+ng the chance under exceptional circ.u.mstances of the derangement of any part of the train.
6. While the broad gauge was but little more costly than the narrow, the width of the works being determined not by the width of the rails, but by the width of the carriages, and the extra cost of rolling stock being very small,[61] the broad gauge could be worked more economically under parallel circ.u.mstances than the narrow.
7. It gave the facility of using broader vehicles with equal steadiness, in cases where the extra breadth would be useful, though the extra breadth was by no means an essential part of the scheme.
The truth of these a.s.sertions, as establis.h.i.+ng the superiority of the broad gauge, was of course vehemently denied by the advocates of the narrow gauge.
One objection urged by them, the inconveniences of the break of gauge, has undoubtedly been proved by experience to be a very powerful one, so powerful indeed as to compel the abandonment of the broad gauge on the lines where any considerable quant.i.ty of goods traffic has to be carried in compet.i.tion with other companies.
Had Mr. Brunel's original plan been carried out, and had the broad-gauge companies taken possession of all the western portions of England, and avoided extensions into the north, the points of contact would no doubt have been so unimportant that no great inconvenience would have arisen, or a few miles of double gauge would have removed any difficulty; but, under the actual circ.u.mstances of the case, the Great Western Company were forced to yield.
The advantages of the broad gauge were so much appreciated by the districts it served, that its abandonment was viewed with considerable displeasure, particularly in the neighbourhood of Birmingham; but the inconvenience of double traffic arrangements far outweighed the advantages derivable from the use of the broad gauge, to the limited extent it could be applied on those outlying portions of the Great Western system. For these reasons the Company came to the determination to work their northern lines on the narrow gauge only.
The broad gauge is therefore now confined to the district for which it was originally intended. Even in this district there are many points of contact with the narrow gauge; but the inconveniences of break of gauge are by no means so important as they were in the north, and do not, at present at least, menace the continued existence of Mr. Brunel's design.
CHAPTER VI.
_THE ATMOSPHERIC SYSTEM._
A.D. 1840--1848. aeTATIS 35--43.
PRELIMINARY OBSERVATIONS--THE SOUTH DEVON RAILWAY--DESCRIPTION OF THE ATMOSPHERIC SYSTEM--HISTORY OF ITS INTRODUCTION PRIOR TO 1844--REPORT BY MR. BRUNEL, RECOMMENDING ITS ADOPTION ON THE SOUTH DEVON RAILWAY (AUGUST 19, 1844)--EXAMINATION OF THIS REPORT--MR.
BRUNEL'S EVIDENCE BEFORE THE SELECT COMMITTEE ON ATMOSPHERIC RAILWAYS, 1845--HISTORY OF THE APPLICATION OF THE SYSTEM ON THE SOUTH DEVON RAILWAY, 1844-1848--REPORT ON STATE OF WORKS (AUGUST 28, 1847)--REPORT ON CAUSES OF FAILURE (AUGUST 19, 1848)--ABANDONMENT OF THE SYSTEM, SEPTEMBER 1848--_NOTE_--COMPARISON OF STATIONARY AND LOCOMOTIVE POWER.
In the year 1844 Mr. Brunel recommended the adoption of the Atmospheric System of propulsion on the South Devon Railway, a line of 52 miles in length, which he was then constructing between Exeter and Plymouth. This system had, under the management of Messrs. Clegg and Samuda, been in operation with success on the Dalkey line for some time before Mr.
Brunel adopted their apparatus on the South Devon Railway. After it had been in use on the South Devon for about twelve months, it was abandoned, and the railway worked throughout by locomotives.
It is therefore as important as it is interesting to examine the causes of the failure of the Atmospheric System, and to consider the reasons which induced Mr. Brunel in the first instance to adopt it, and afterwards to recommend its abandonment.
Up to about the year 1843, the cost of railways, which was in a great measure due to the conditions imposed by the limited capabilities of the locomotive, had prevented their construction, except in cases where they would secure a large traffic, and at the same time traverse what was then considered a practicable country.
<script>