Wally No. 2, a robotic camera and toy tank look-alike, crawls through a 24-inch stormwater pipe beneath Signal Mountain's W Road, trying to show why one lane seems to be inching off the mountain.
"That's a big break in the pipe right there," said Michael McNair, watching a computer screen inside his truck Thursday as he guided the robot deeper into the pipe beneath a 50-foot section of the heavily traveled, winding road.
Looking on, Hamilton County Highway Department Director Harold Austin and Roads Supervisor Gary Bean tried to figure out a way to permanently fix the sinking road before the entire uphill lane slips away.
"We'll probably try to see if we can put a slip-liner in the pipe," Austin said. "Or we may just put in a whole new pipe.
"But we won't do it today. ... The road's as safe as it's ever been," he said.
The W Road was shut down for most of Thursday - at a cost of about $3,000 for asphalt and the labor of about 20 county workers - so Austin and others could analyze the sinking problem that travelers and road workers have been watching for almost a year.
The crescent-shaped area, near the top of the W and just below the road's lowest switchback, was patched with adhesive tar in the spring after the pavement cracked and one side dropped about five inches.
"We've got some movement up there," Austin said at the time. "We think it's all right. We are continuing to keep an eye on it."
It was just one event in a cascade of highway problems that began late last year. A sinkhole that opened in December sent a big section of Signal Mountain Road slumping into the valley below. There were two major rock slides in the Ocoee Gorge, at least two rock falls on Cummings and Scenic highways on Lookout Mountain and two mudslides on the W Road over the winter and spring.
On Thursday, Roads Supervisor David Pierce said the section sank another five inches over the past six months, bringing workers back to investigate.
Wally No. 2 - so named because "it often crawls through lots of No. 2," said wastewater technician McNair - belongs to the Hamilton County Wastewater Treatment Authority, as does the video truck and its operator.
As McNair worked, a county backhoe operator peeled up about a foot of pavement and rock from the sinking section of roadway.
"We're going to open it up and see what's going on," said Ben Wilson, another county roads superintendent.
The road reopened shortly after 4 p.m. Thursday, in time to handle the evening rush-hour.
A more permanent fix might take a little longer, perhaps two days, Austin said.
"If we have to put a new pipe in, we'll have to cut the road. If we hit rock, it could take us two days," he said.
"But whatever we do, we'll do it before the [seasonal] rain sets in. Hopefully it will be sometime next week," he said.
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