The remaining sections of the railway named after the tunnel abound in interesting features from the technical point of view, the most notable, possibly, being the remarkable spiral tunnels to which reference has been made, and the successful application of which in this instance has been reproduced upon other railways where similar conditions prevail. The best examples, possibly, are those by which the Biaschina gorge is negotiated, since here there are two of these tunnels side by side, the railway almost describing a figure 8 in corkscrewing from one level to the other. Exclusive of the Gotthard, there are no less than 76 tunnels and galleries, aggregating 29 miles, as well as 1,384 other structures, 324 being bridges and viaducts over 39 feet in length. In one stretch of 7 miles, in skirting the south-eastern arm of the Lake of Lucerne, the railway passes through 9 tunnels, ranging from a mere 85-feet burrow to others 6,512 feet in length. Among the Gotthard fastnesses the railway work becomes bolder, the bridges are lofty, while the line zigzags in a remarkable manner. It is a case of tunnel, cut and bridge all the way. Up to 1880, when the railway was finished practically, constructional work provided regular employment for 10,757 men. So rapidly did the volume of traffic upon the railway swell, however, that it became extremely difficult to handle it, as there was only a single line, except in the tunnel and at one or two other points. The provision of another track became imperative, and in 1886 it was commenced. This was not a simple matter, as the new work had to be carried out without interrupting traffic in any way--that is, so far as the main through service was concerned. With the exception of the Gotthard and four smaller tunnels, all the other structures had to be excavated out to carry the second pair of metals, while, similarly, all bridges had to be increased in width. In order to finish the work as rapidly as possible, the task was divided up into a number of small, separate contracts, each covering a few miles. Vehicles for the conveyance of constructional material were provided and supplies were hauled free of charge by the railway, while explosives for blasting were sold at cost price.