131. This Contractor shall submit an alternate
proposal for furnishing and installing a trolley beam for the Movietone
Horns. It shall be a six (6") inch
I-beam suspended from the gridiron by three-quarter (3/4") rods. These rods shall have turnbuckles for
leveling. All joints in the I-beam shall be milled faces and splice plates both
top and bottom to keep the beam perfectly straight. The I-beam shall be anchored to the side
walls of the building to prevent swaying.
On the I-beam there shall be two (2) steel cages for the horns. These cages shall have noiseless ball bearing
trolley wheels and cages shall travel right and left and shall be operated by an
endless line running over eight (8") inch ball bearing blocks. The operating line shall be one-half
(1/2") inch cotton sash cord. The
cages shall be so constructed that draperies and soundproof material may be
attached on back and sides.