An engine turn-table is a costly item in railway requirements, not only in the girder-work, but in the large amount of building in the side walls and centre pier, and an effort is always made to avoid the outlay unless the table can be placed where it may be of permanent use. In the construction of foreign railways, and in our colonies, where the lines are opened in sections as the work goes forward, the temporary arrangement shown in Fig. 443 is frequently used instead of an engine turn-table. The sketch will almost explain itself. On the main line, A, B, C, D, switches are placed at B and C, from which turn out curved lines, uniting at the switches E. An engine proceeding from A, and passing round the curve B, E, G, then round curve G, E, C, and back along main line, D, C, B, A, will be turned round as efficiently as on a turn-table. The writer has used this arrangement abroad with great advantage. It involves very little work or expense beyond laying down the permanent way, and so soon as the temporary terminus of the 292 line has been advanced further ahead, the rails and sleepers can be lifted and used again elsewhere. Figs. 444 and 445 give sketch plan and section of a waggon turn-table which has been largely adopted. The centre should be securely fixed on a solid foundation of masonry, brickwork, or concrete. The deep outer cast-iron ring is made in segments, properly fitted and bolted together, and fastened down to the foundation course. The stop-checks are cast on to this outer ring. Two roads, at right angles to each other, are laid on the turn-table, so that waggons to or from the goods-shed have only to make one quarter turn of the table. The top is generally covered with either chequered iron plates or timber to give good foothold for the men and horses which have to pass over in moving the waggons. If properly balanced, the table is easily turned by men pushing at the opposite corners of the waggon, or by a horse and tail-rope, or by hydraulic power through a capstan. In many cases of bad or soft foundations these small turn-tables are erected on a strong framework of creosoted timber. Carriage turn-tables are now very rarely used. With the old short four-wheeled carriages the moderate-size turn-table was convenient for transferring an extra carriage to or from a spare carriage-line alongside the making-up train at a platform, but modern carriages are now so much longer, some of them twice the length, or more, than formerly, that nothing less than an engine turn-table would be large enough for them. Sometimes a carriage traverser is used for this station work, but much more frequently these long carriages are shunted on or off the making-up train by simply running them in or out through the nearest switches and cross-over road. [Illustration: Fig. 446, 447]