The hook - headed spikes t, commonly used for confining rails to the cross-tiea, vary within the limits of the following table; the lightest ones for light rails on short local branches; and the heaviest ones for heavy rails on first-class roads. The table is from the Phoenix Iron Company of Philadelphia. The spikes are sold in kegs usually of 150 pounds. For the weight of spikes of larger dimensions, we may near enough take that of a square bar of the same length. What is saved at the point, suffices for the addition at the head.

Fig.43.

 Size in ins. No. per keg of 150 lbs. No. per lb. Length. Side. 4½X7/16 626 3.5 4½X ½ 400 2.66 5 X 3/8 705 4.7 5 x 7/16 488 3.25 5 X ½ 390 2.6 5 X 9/16 295 1.97 5 X 5/8 257 1.71
 Size in ins. No. per keg of 150 lbs. No.per lb. Length. Side. 5 ½X ½ 350 2.33 5½ X 9/16 289 1.93 5½ X 5/8 218 1.46 6 X ½ 310 207 6 X 9/16 262 1.75 6 X 5/8 196 1.30

A size in very common use is 5½ X 9/16 which weighs about ½ pound per spike. A mile of single-track road, with 2,112 cross-ties, 2½ feet apart from centre to centre, and with rails of the ordinary length of 24 feet, or 10 ties to a rail, thus having 440 rail-joints per mile, with 4 spikes to each tie, except at the rail-joints, at each of which there will be 4 spikes, † will require, at a neat calculation, 9,328 spikes.

But an allowance must be made for rail guards at road-crossings, which we may assume to be 24 feet wide, or the length of a rail. A guard will usually consist of 4 extra rails for protecting the track rails, and spiked to the 11 ties by which said track rails are sustained. Consequently, such a crossing requires 11 X 8 = 88 spikes. For turnouts, sidings, loss, etc., we may roughly average 584 ‡ spikes more per mile; thus making in all (if we assume one road-crossing per mile) 9328 + 88 + 584 = 10,000 spikes per mile, or 5000 pounds, or 33 1/3 kegs of 150 pounds.