SILVER SPRING, Md. — It was a bold construction move that took a year to plan.
Thursday, the final act of a slow-motion, heavyweight aerial ballet of steel took about 15 minutes to carry out as a 300-ton crane lifted a bridge off its footers and gingerly delivered it to a wood-plank roadway below.
"It's 143 feet long and 85,000 pounds," marveled Ken Price, a civil engineer who is the construction manager on the Purple Line transit project now under construction between Bethesda and New Carrollton.
Price was overseeing the removal of a steel bridge where the old Capital Crescent Trail built over an historic rail right of way towers over Rock Creek.
A new bridge will be built in its place to carry the future Purple Line light rail system.
Crews clad in climbing gear and helmets wrangled ropes to keep the flying behemoth from spinning out of control into the crane's massive boom.
It was a dangerous job, executed flawlessly.
The bridge removal job required the construction of a special roadway to carry the truss away and support the crane safely near the banks of the creek.
"I think its great," said Charles Lattuca, the Senior transportation executive charged with leading the $5.6 billion Purple Line Light Rail Project for the Maryland Transit Administration. "We're making some progress on this job and this is a big part of it."
The bridge removal was a reminder of the scale of the $5.6 billion Purple Line project which when complete will be the largest transportation project ever constructed by the State of Maryland.
The job is now 15% complete and on track to be moving passengers by late 2022 or early 2023, Lattuca said.
Legal challenges have delayed the job by at least a year and added up to $200 million in additional construction cost.
The construction of a tunnel under Plymouth Street on the east side of Silver Spring has proven to be the most disruptive part of the job so far.
Neighbors were outraged by a 24-hour schedule that included overnight underground blasting and rock-hammering that rattled homes and shook people from their sleep.
Eventually, state officials relented on the most disruptive overnight work, and the blasting and rock hammering part of the job is now complete.
"We're not going to be tunneling under somebody's house like we were before," Lattuca promised.
But new disruptive troubles are ahead.
Among the most challenging will be the construction of the surface rail system directly through the center of the University of Maryland campus. Preparatory work is underway and traffic tie ups on Campus Drive are already annoying many students.
When finished, the Purple Line will provide a 16.2 mile link between New Carrollton and Bethesda. The light rail system will tie together the Red, Green and Orange Metro lines and is projected to carry as many as 74 thousand daily riders by 2040.