Note 78 — Chapter VII · RAILWAY BRIDGES AND VIADUCTS.

In the early days of the Great Western Railway special designs were made for every one of the ordinary bridges over and under the railway; but when, in consequence of the rapid extension of the Great Western system, the number of bridges to be designed became very large, Mr. Brunel had a set of ‘standard drawings’ prepared and engraved, which embodied the experience gained, and contained designs suitable for various situations. The contract drawings were made by adapting to the particular circumstances of each case the standard drawing which was most applicable to it. This system, besides securing uniformity of construction, introduced a considerable amount of economy; since, the standard drawings being based upon the results arrived at in an extensive practice, the proper structural arrangements and dimensions were indicated with far greater accuracy than could be attained in a reasonable time by an independent calculation in each individual case.