RAILROAD LOCATION AXD CONSTRUCTION — MACKENZIE. 121 



30 



35 



40 

 45 

 50 

 55 

 60 

 65 

 70 

 75 

 80 



85 



90 



95 



100 



Cost, etc., of Steel Bridges (metal only), designed for Typical 

 Consolidation Locomotives. Compiled from formulas hy 

 G. H. Pegram, G. E. (Trans. A. S. C. Engrs., Feb. 1SS6.) 



o 

 (9) 



S510 00 



644 00 

 840 00 

 990 00 

 1160 00 

 1364 00 

 1560 00 

 1743 00 

 2002 00 

 2250 00 

 2790 00 



3060 00 

 3361 50 

 3676 -50 

 4050 00 



For double track add 90 %. — Cols. 7, 8 and 9 will vary with 

 the market price of steel. 



Bridge- Erection on Raikuays in operation. — Plate-girders up 

 to 75 feet span are usually riveted up complete, run into place 

 on cars, and lowered on to the masonry by four screws working 

 through overhead caps, supported on two posts at each end of 

 bridge. 



Deck bridges from 75 feet to 100 feet are riveted up complete, 

 run into place on cars, jacked up, and the weight taken on 

 blocks hung from overhead gallows-frames. The cars are then 

 run out and the old bridge removed, when the new bridge is- 

 lowered to its place on the masonry by means of the blocks. 



Through bridges may be placed the same as Decks, by spread- 

 ing the old trusses far enough to let the new bridge in between 



