SPECIFICATIONS. 297 



22. Girts. Girts shall be properly framed and securely fastened to caps, sub-nib, posts or 



piles, .is the plans may require. 



23. Stringers. -Striii^-rs shall be sized to a uniform height at supports. The edges with 

 most sap shall bo placed downward. 



24. Jack Stringers. Jack stringers, if required on the plans, shall be neatly framed on 

 caps, .iin 1 their tops shall be in the same plane as the track stringers. 



25. Ties. Ties shall be framed to a uniform thickness over bearings, and shall be placed 

 with tlu- rough side upward. They shall be spaced regularly, cut to even length and line, a* 

 calk-cl for on the plans. 



26. Guard Rails. Timber guard rails shall be framed as called for on the plans, laid to line 

 and to a uniform top surface. They shall be firmly fastened to the ties as require* I. 



27. Bulkheads. Bulkheads shall be of sufficient dimensions to keep the embankment clear 

 of the caps, stringers and ties, at the end bents of the trestle. There shall be a space not less 

 than two (2) in. between the back of end bent and the face of the bulkhead. The projecting 

 ends of the bulkhead shall be sawed off to conform to the slope of the embankment, unless other- 

 wise specified. 



28. Time of Completion. The work shall be completed in all its parts on or before . . 

 A. D. 19.... 



29. Payments. Payments will be made under the usual regulations of the railroad company. 



SPECIFICATIONS FOR METAL DETAILS USED IN WOODEN BRIDGES AND TRESTLES. 



30. Wrought-iron. Wrought-iron shall be double-rolled, tough, fibrous and uniform in 

 character. It shall be thoroughly welded in rolling and be free from surface defects. \Vlu-n 

 tested in specimens of standard form shall give an ultimate strength of at least 50,000 Ib. per sq. 

 in., ah elongation of 18 per cent in 8 in., with fracture wholly fibrous. Specimens shall bend cola, 

 with the fiber, through 135 degrees, without sign of fracture, around a pin the diameter of which 

 is not over twice the thickness of the piece tested. When nicked and bent, the fracture shall show 

 at least 90 per cent fibrous. 



31. Steel. Steel shall be made by the open-hearth process and shall be of uniform quality. 

 It shall contain not more than 0.05 per cent sulphur; if made by the acid process it shall contain 

 not more than 0.06 per cent phosphorus, and if made by the basic process not more than 0.04 

 per cent phosphorus. When tested in specimens of standard form, or full sized pieces of the 

 same length, it shall have a desired ultimate tensile strength of 60,000 Ib. per sq. in. If the 

 ultimate strength varies more than 4,000 Ib. from that desired, a retest shall be made on the 

 same gage, which to be acceptable, shall be within 5,000 Ib. of the desired ultimate. It shall 



have a minimum percentage of elongation in 8 in. of - -r and shall bend cold with- 



^ ult. tens, strength 



out fracture 180 degrees flat. The fracture for tensile tests shall be silky. 



32. Castings. Except where chilled iron is specified, castings shall be made of tough gray 

 iron, with sulphur not over o.io per cent. They shall be true to pattern, out of wind and free 

 from flaws and excessive shrinkage. If tests are demanded, they shall be made on the "Arbi- 

 tration Bar" of the American Society for Testing Materials, which is a round bar 1} in. in diameter 

 and 15 in. long. The transverse test shall be made on a supported length of 12 in., with load at 

 middle. The minimum breaking load so applied shall be 2,900 Ib., with a deflection of at least 

 xV in. before rupture. 



33. Bolts. Bolts shall be of wrpught-iron or steel, made with square heads, standard size, the 

 length of thread to be 2 J times the diameter of bolt. The nuts shall be made square, standard size, 

 with thread fitting closely the thread of bolt. Threads shall be cut according to U. S. standards. 



34. Drift Bolts. Drift bolts shall be of wrought-iron or steel, with or without square head, 

 pointed or without point, as may be called for on the plans. 



35. Spikes. Spikes shall be of wrought-iron or steel, square or round, as called for on the 

 plans; steel wire spikes, when used for spiking planking, shall not be used in lengths more than 

 6 in.; if greater lengths are required, wrought or steel spikes shall be used. 



36. Packing Spools or Separators. Packing spools or separators shall be of cast-iron, made 

 to size and shape called for on plans; the diameter of the hole shall be J in. larger than diameter 

 of packing bolts. 



37. Cast Washers. Cast washers shall be of cast-iron. The diameter shall be not less than 

 3i times the diameter of bolt for which it is used, and its thickness equal to the diameter of bolt; 

 the diameter of hole shall be i in. larger than the diameter of the bolt. 



38. Wrought Washers. Wrought washers shall be of wrpught-iron or steel, the diameter 

 shall be not less than 3 \ times the diameter of bolt for which it is used, and not less than J in 

 thick. The hole shall be \ in. larger than the diameter of the bolt. 



39. Special Castings. Special castings shall be made true to pattern, without wind, free from 

 flaws and excessive shrinkage, size and shape to be as called for by the plans. 



