Handbook of Railroad Construction; For the use of American engineers. / Containing the necessary rules, tables, and formulæ for the location, construction, equipment, and management of railroads, as built in the United States.

by George L. Vose

b = 15000 × 1440
5000 × 256 = 21600000
1280000 = 16 inches.

CAST-IRON.

163. The formula, expressive of the strength of a cast-iron beam, is

850bd² = WL,

from which we have

b = LW
850d² = the breadth,

and d = √(L × W
850b) = the depth.

WROUGHT IRON.

164.

952bd² = WL,