Heavy rigging and transportation specialist Omega Morgan has handled the delivery of a 209-tonne transformer for the Bonneville Power Administration (BPA) Rock Creek substation.
Loaded on to a 48-axle trailer, measuring 360 ft (109.7 m) in length, the combination weighed nearly 454 tonnes - one of the heaviest combinations in Washington state history.
Omega Morgan used three heavy haul Kenworth trucks to accomplish the 47 mile (75.6 km) move from Sundale, Washington to the substation. A Kenworth C500 acted as lead truck with two Kenworth T800s as the pushers.
“For this transport, there were quite a few obstacles we had to plan for, not to mention two-lane roads that had to be closed,” said Troy Tallent, vice president of operations at Omega Morgan.
“For instance, we had to widen the gravel road from 16 ft (4.87 m) to 20 ft (6.1 m), and reduce the grade by the rail head (where the transformer was lifted off the railcar and placed in the trailer-cradle) from 16 percent to 15 percent.”
A fourth truck, loaded with concrete blocks, was tethered to the C500 to ensure sufficient traction to haul the combined weight up the slope.
The route also included steep downhill sections that demanded careful control of the vehicles, bridges requiring hydraulic dollies to spread the load, tight turns (greater than 90 degrees) and a 14 mile (22.53 km) stretch of road with only a 12 inches (30.1 cm) to spare on either side of the trailer.