Late last year—working nights under very tight time constraints—a Wirtgen W 2200-12 cold mill with 12-ft 6-in.-wide drum worked with smaller Wirtgen mills to remove asphalt from a main runway at Ronald Reagan Washington National Airport (DCA).
There the W 2200-12, Wirtgen’s then-largest mill, expedited milling of Runway 1-19 plus tie-backs into all adjoining taxiways, a total of nearly 300,000 sq yd. When visited, milling contractor Mark-Lang Inc. was removing the intersection of runways 1-19 and 15/33.
“The intersection work requires a hard closure,” said Charles Boswell, secretary/treasurer of Mark-Lang Inc., Millersville, Md. “We typically will have from 1 a.m. to 6 a.m. to do the work. It’s got to be open to air traffic by 6 a.m. so we really only have until 4:30 a.m. to do any construction. After that we have to be cleaning up the area and getting off the airfield.”
Every night is different, Boswell said. “This job is not as straight a cut as a ‘shave-and-pave’ project,” he said. “We’re basically profile-milling, or fine-grading, the runways. Survey teams check elevations and determine what needs to be cut to place 3 in. of asphalt back on top. As a result we will remove anywhere from 1 in. to as much as 7 in. in some areas, but the majority is 3 to 4.5 in.”'
For this work, Mark-Lang was using a W 2200 with a 12-ft 6-in. fine-texture drum and a W 210 with a fine-texture drum. Cutting tools were spaced at 5?16 in. Wirtgen’s exclusive Level Pro system was making the critical adjustments in runway milling easier for Mark-Lang.
“[The system] allows us to control both sides of the machine at the same time from one controller,” said Boswell. “The controllers talk to each other, too. If you change entries on one monitor it will show up on the other.
“Not only that: When we’re cutting shoulder edges we tend to run slope for that, and you can see your slope in the center screen, or your depth,” Boswell said. “You are able to monitor your depth while still seeing the slope, and it allows a lot of functionality for the guys running ground controls.”
In 2011 the W 2200 was replaced with the new Wirtgen W 250, which features many improvements over the W 2200. R&B