This 1928 cover shows two railway erection cars that build the new main bridge on the main line of the Pennsylvania railway on the Wabash River in Terre Haute, Ind.
Various techniques were used in this work that advanced the method to place the plate beams at a new level.
The 125 feet of 70 tonne length that rises to the position is heavier than any beam placed by erection cars before.
Standard erection cars were 50 feet long and equipped with a 50 -foot boom and included standard assembly and counterweight engines.
The platforms that appear here, however, have 70 -foot tail booms and tail beams, which take the horizontal component of the boom voltage.
Each queue beam, which extends beyond their erected car, was located to rest on a bogie and 28 tons of additional pork iron counterweight.
Erigent cars were equipped with auxiliary booms linked to the sides of cars to anchor cars against the ball when heavy loads were changed.
A steel equilibrium beam was used to divide the weight of the beam in equal parts between the two erected cars. Seaboard Construction Co., from Philadelphia, is doing the work seen here.
The eight double -track extensions on the bridge included 32 beams, which were erected in 35 working days.
