Tappan Zee Bridge Zipper’s days are numbered

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A big yellow bus ran into the wall on the Tappan Zee Bridge, the caller tells the 911 operator.

“It’s not a bus. It’s us,” says Richie Lynch of Valley Cottage, one of the drivers of the barrier-moving machine that is still a strange sight for the uninitiated, even 22 years after first arriving on the bridge. Callers regularly report the vehicle as an accident in progress, Lynch says.

“Some people drive by and take pictures,” says Lynch, who has worked on the bridge for 25 years. “We get a lot of thumbs-ups for giving them the extra lane. And we get a different salute when we’re running late.”

Some call it “The Zipper” — because it acts like a zipper does, sliding the barrier from one spot to another — but Lynch and the four other members of the barrier team just call it “the barrier mover.”

Whatever the name, the 52-foot-long, million-dollar vehicle is now part of the bridge, a welcome sight for bumper-to-bumper commuters on whom it bestows a somewhat speedier ride through the Tappan Zee bottleneck, creating four lanes where there were three. It makes about 600 crossings a year.

In January, a Zipper was added to San Francisco’s storied Golden Gate Bridge. But the Tappan Zee Zipper’s days are numbered.

In December 2016, northbound traffic is scheduled to transfer to the new northbound span of the New New York Bridge. The two barrier movers — there’s an extra on standby, swapped in during maintenance — will be sold and will enter the lore of the Tappan Zee, alongside those pre-EZPass commutation booklets.

VIDEO BELOW: Ride inside the Zipper  

ALSO: What do the new TZ Bridge and a NASCAR track have in common? 

The Zippers — the second-generation of vehicle by California-based Lindsay Transportation Systems, in use since 2007 — move the wall 12 feet to the right, the width of a travel lane, in one fluid motion with every trip across the bridge. It used to take two machines to make the move.

The wall itself is second-generation, too. The original had concrete sections; today’s sections — there are 6,000 of them, each 3 feet long — are T-shaped steel shells with a concrete center.

There is so much more going on than meets the eye when the Tappan Zee Zipper is in motion. The barrier is shaped and reformed through hydraulics and an ingenious machine that acts like a chiropractor on a 3-mile-long Tappan Zee spine, adjusting and releasing tension in the wall — and in rush-hour traffic.

Driving and laying: The Zipper doesn’t drag the wall. It lifts it, snakes it through a double row of wheels in its undercarriage, and places it back on the deck. In a sort of push-me-pull-you configuration, a second driver — facing the shore from which the Zipper departed — “lays” the barrier back in position by keeping a wheel on one of the blue lines on the pavement.

“When you drive on it, all you’re doing is engaging it on the wheels and lifting it up,” Lynch says. “When it gets to the middle of the machine, that’s where it starts to shift it to the other side, and then the conveyor takes it down and sets it back onto the deck.”

“Bogey wheels:” The 104 wheels that engage the T-top and lift the barrier are called “bogey wheels” and glide the barrier up a railing under the vehicle and help it snake into its new position.

A “wow” in the wall: Ernie Feeney, a patrol supervisor and another original Zipper driver, says the wall sometimes gets a kink in it, when a motorist hits it.

“We call it a ‘wow,'” Feeney says. “Maybe somebody spun out and hit the wall. The wall gives now because it’s a giant centipede so your car doesn’t get totally wrecked like it used to be if you had a solid cement wall. A lot of people now just drive off with minor damage.”

When the barrier machine comes across, if there’s just a little “wow” in the wall, they can just drive straight through it. A bigger accident requires a wrecker and a push bar to get it close to its natural line.

Stop the Zipper: There are things that will stop the barrier in its tracks, Lynch says. “If there’s a jumper in the middle of the move, we’ll stop. If there’s a bad accident or if there’s an accident in the left lane or the two left lanes, sometimes we’ll bring the wall up to it and stop to protect them.”

Migration lines: Like rush-hour commuters, the barrier is under tension. There are yellow lines on the wall that correspond to lines on the deck. If these migration lines don’t line up, the Zipper driver can adjust huge capstan wheels to add or release tension in the wall to pull or push it back in line.

Hydraulics, Benjamin: “It’s all done by hydraulics,” Lynch says. “Your steering, your brakes, the drive motors, it’s all hydraulics. And those lines and fittings need to be checked every day to make sure they’re not leaking.”

Every 20 feet or so on the flat sections (and farther away on the inclines) there are single open-topped T sections. These “VLB sections” actually control the tension in strands of the barrier. They have hydraulic controls in them and open and close to allow strands of the wall to go slack and be moved. Think of it as pulling a 3-mile-long rope 20 feet at a time. On curves, there are more VLB sections to hold the curve in place until the machine reaches it.

No connection: The barrier mover isn’t connected to the wall. It has to drive onto the wall. When he’s driving, Lynch keeps a control bar centered over the wall ahead of him.

3 miles, 30 minutes: The move takes about 35 to 40 minutes, if the wall is in good shape. “If there’s more tension or compression, it might take a little longer because you have to go through it slower to make the adjustments,” Lynch says.

U-turns possible: Eagle-eyed drivers will notice three 45-foot sections of bridge where the T-tops appear to be hollow. There are three spots on the bridge — near either end and in the middle — where the barrier can be opened to allow for a U-turn.

Hello, I must be going: “The men and all of us are going to miss it,” Lynch says. “And I think the public’s gonna miss it, too. It’s nice to have an extra lane when you need it.”

NYS Thruway employee Rich Lynch drives the barrier-moving machine across the Tappan Zee Bridge, adding a lane northbound. Tania Savayan/The Journal News

http://www.lohud.com/story/news/local/tappan-zee-bridge/2015/07/16/tappan-zee-bridge-zipper-days-numbered/30142559/

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