It frequently happens, in cases where a traveller road has to be supported on one side on a row of columns and on the other side by a wall, that on the wall side special arrangements of girders to carry the rails have to be provided, while their details are determined by the special conditions existing of openings in the walls for light or access, dimensions and spacing of piers, buttresses, or the like.

Examples of some such structure are shown in the accompanying illustrations.

Fig 72 shows in elevation the connection between the ends of two traveller girders, meeting together upon a masonry pier. Fig. 73 shows a cross-section of the girder near the pier, while Fig. 74 shows the section at the centre of the span. It will be observed that the section of the bottom flange consists of two plates in addition to the main angles, while the top flange at the centre is similar. At the ends, however, while one plate of the bottom flange is stopped off, the two plates in the top flange are run on continuously in order to provide a uniform bed for the rail, the plate continued being in fact a packing, which, had it not been that the clips should be all off one pattern, might for economy sake have been no wider than the rail foot.

Fig. 71. Scale ¾ inch = 1 foot.

Fig. 72. Scale ¾ inch = 1 foot.

Fig. 73. Scale ¾ inch = 1 foot.

Fig. 74. Scale ½ inch = 1 foot.

Fig. 75. Scale 3 inches = 1 foot.

Fig. 76. Scale 3 inches = 1 foot.

Fig. 77. Scale ¾ inch = 1 foot.

Fig. 78. Scale ¾ inch = 1 foot.

The important dimension above referred to, viz. the distance between centre line of traveller rail and the adjacent wall is in this case 11 inches. This leaves a net distance of 5 inches between the girder and the wall, and, to avoid any trouble in getting at the work, the lewis bolts securing the girder to the cap stone of the pier are shown on the outer side only; these bolts consisting of ⅞-inch diameter lewis or rag bolts. Similar bolts of ¾ inch and 1⅛-inch diameter are shown on a larger scale in Figs. 75 and 76.

Fig. 79. Scale ¾ inch = 1 foot.

Fig. 80. Scale ¾ inch = 1 foot.

The seating of the girder on a pier at an end wall is shown in Figs. 77, 78. Figs. 79, 80 show a method of affording lateral stiffness to a rolled joist traveller girder alongside a wall.

The important subject of the design and details of lofty columns supporting systems of traveller roads, etc., will be found dealt with in Chapter IV (On The Practical Design Of Columns And Struts)., on the Practical Design of Columns and Struts, where examples of such columns will be found.