Page:Steamlocomotivec00ahrorich.djvu/94

 CHAPTER VIII ERECTING SHOP Frames. In the erecting shop all the parts which make up the complete locomotive are assembled and put together. The frame plates, which form the foundation of the engine, are first taken in hand, and are placed in position on opposite sides of a long pit. This pit is made in the floor of the shop between the rails on which the engine will stand later after the wheels have been placed in position. The frames are placed vertically in their natural position, and rest in grooves made in the heads of screw jacks. By means of these jacks the frames can be levelled, and set in the exact positions required. The frame plates are held temporarily at their proper distance apart by long bolts and distance pieces, until the permanent stays are fastened to them. They are then levelled both longitudinally and transversely by means of long straight edges upon which spirit levels are placed. Their vertical adjustment is made by plumb lines. Both frames must be placed exactly opposite to each other in their proper relative positions. This adjustment is made by placing straight edges across the faces of the hornblocks, and using “trammels.” A trammel is a long steel rectangular bar with sliding compass points, the latter being set to a Rh