2d. At least eight (8) points of support on the drum will be needed.

DETAILS OF DESIGN FOR PIN-CONNECTED
DRAW-SPANS.

The specifications for the corresponding item in the Specifications for Highway Bridges are to be followed, and in addition thereto those given under the heading "Details of Design for Trusses of Draw-Spans" in the Specifications for Railroad Draw-Spans are to be employed, except that the use of adjustable members for lateral diagonals will be permitted in the case of cheap highway draw-spans.

DETAILS OF DRUMS AND TURNTABLES.

In general the Specifications for the corresponding item in the Specifications for Railroad Draw-Spans shall be followed, except that, for light, highway draws, the limiting thicknesses, etc., may be reduced to the following:

Top flanges and webs of drums— three eighths (3/8) of an inch.

Bottom flanges of drums— five eighths (5/8) of an inch.

Upper track segments— one and three-quarter (1 3/4) inches.

Lower track segments— two (2) inches.

Bearing-plates over drum— three quarters (3/4) of an inch.

Centre casting on pivot-pier— one (1) inch.

Anchor-bolts for same— one and one-eighth (1 1/8) inches in diameter and two and a half (2 1/2) feet long.

Rollers— ten (10) inches in diameter and six (6) inches face.

MACHINERY FOR TURNING THE SPAN AND LIFTING
THE ENDS OF SAME.

See Specifications for Railroad Draw-Spans.

METHOD OF DETERMINING POWER REQUIRED FOR
OPERATING THE SPAN AND LIFTING THE ENDS.

See Specifications for Railroad Draw-Spans.