The transportation from one point to another within the tunnel and its shafts of any material, whether it is excavated spoil or construction material, is defined as hauling. In all engineering construction, the transportation of excavated materials, and materials for construction, constitutes a very important part of the expense of the work; but hauling in tunnels where the room is very limited, and where work is constantly in progress over and at the sides of the track, is a particularly expensive process. Hauling in tunnels may be done either by way of the entrances, or by way of the shafts, or by way of both the entrances and shafts.
Fig. 33.—Platform Car for Tunnel Work.
Hauling by Way of Entrances.
—When the hauling is done by the way of the entrances, the materials to be hauled are taken directly from the point of construction to the entrances, or in the opposite direction, by means of special cars of different patterns. For general purposes, these different patterns of cars may be grouped into three classes,—platform-cars, dump-cars, and box-cars. Representative examples of these several classes of cars are shown in [Figs. 33] to [36][6] inclusive, but it will be readily understood that there are many other forms.
[6] Reproduced from catalogue of Arthur Koppel, New York.
Briefly described, platform-cars ([Fig. 33]) consist of a wooden platform mounted on tracks, and they are usually employed for the transportation of timber, ties, etc. Dump-cars are used in greater numbers in tunnel work than any other form. [Fig. 34] shows a dump-car of metal construction, and [Fig. 35] one constructed with a metal under-frame and wooden box. These cars are made to run on narrow-gauge tracks, and usually have a capacity of about one to one and one-half cubic yards. Box-cars are more extensively employed in Europe for tunnel work than in America. [Fig. 36] shows a typical European box-car for tunnel work. It is made either to run on narrow-gauge or standard-gauge tracks.
Fig. 34.—Iron Dump-Car for Tunnel Work.