Light rail saga has unusual twists

ZIG, ZAG, ZIG GOES THE TROLLEY

March 30, 1992|By Peter Jensen | Peter Jensen,Staff Writer

They call it the "Rebel Yell."

The people who created Baltimore's new Central Light Rail Line borrowed the name from the roller coaster at King's Dominion -- or else from the brand of bourbon. Who knows for sure?

Like the amusement park ride near Richmond, Va., this Rebel Yell twists and veers, climbs and then falls abruptly.

Like the potent Southern whiskey, it has caused its designers some powerful headaches.

When the light rail system begins limited operations to and from Orioles home games, starting with Friday's exhibition against the New York Mets, riders will have a chance to meet the Rebel Yell firsthand.

Frankly, the original roller coaster is a better ride. But without the 1,200 feet of curving track that represents Baltimore's Rebel Yell, the light rail system might never have been made, or at least have cost millions of dollars more to build.

"It's a unique piece of track, no doubt about that," said John W. von Briesen, an engineer who oversaw construction of the $446.3 million rail project for the Mass Transit Administration. "It was one of the most difficult obstacles to figure out and calculate. If it hadn't worked, we would have been in trouble."

The Rebel Yell was born of necessity four years ago when Gov. William Donald Schaefer announced his intention to build a modern trolley system through Baltimore. Ultimately, he promised, the light rail line would link Hunt Valley with Glen Burnie by way of downtown Baltimore.

To accomplish this, the MTA would have to acquire two railroad lines, the former Northern Central Railway along the Jones Falls Expressway and the Baltimore & Annapolis through northern Anne Arundel County.

Howard Street was a natural choice to connect them through downtown. It aligned directly with the B&O warehouse and the future Oriole Park at Camden Yards and was already closed to through traffic.

But how to join the Northern Central with Howard Street in a way that would allow the system to branch out to Penn Station? That was the daunting challenge.

The area around Mount Royal and North avenues was an intricate lacework of overpasses, tunnels and roads even before light rail was contemplated. Nowhere in the city is transit more complex.

At the lowest level is the tunnel accommodating Amtrak, the primary East Coast passenger rail line. Above is the six-lane Jones Falls Expressway, the city's major highway to the northern suburbs.

In between, engineers had to clear the North Avenue and Howard Street overpasses and avoid interfering with another railroad right-of-way, CSX Corp.'s main freight route to Philadelphia, which runs across the same section of the Jones Falls corridor.

"It was hell," said Peter J. Schmidt, MTA's assistant general manager for development, who is credited with devising the Rebel Yell solution. "I thought it could be made to work. It turned out to be the only way we found that could work."

Here's how they did it: From north to south the tracks first go underneath North Avenue, turning right and over the Amtrak tunnel 25 feet below. Next, the line continues right and under the Jones Falls Expressway, after which it takes a hard left and begins to rise.

The rail runs parallel to the expressway for 200 feet and starts down again. At this point it crosses the CSX line, over which the MTA had to build a concrete bridge.

Next, it continues underneath the Howard Street Bridge, then turns right and goes back up, maintaining a flat grade at this point so that eventually the spur to Penn Station can be added.

From there it crosses Mount Royal along the University of Baltimore parking lot, with a sharp right turn and then a left down Howard Street. Simple, right?

For those not keeping track, that was a hard right, a hard left and a hard right with a simultaneous up and then down and then back up.

Not impressed? Well, where the light rail line goes under Howard Street and the Jones Falls overpasses, the clearance is 13 feet 7 inches. The minimum the light rail needed for its 750-volt overhead power lines was 13 feet 6 inches.

Cleared it by an inch.

The steepest grade the trolley system was made to handle is 6 percent, or a rise of six vertical feet for every 100 feet of horizontal track. The Rebel Yell would have a 7 1/2 percent grade as it dipped under Howard Street.

Missed it by 1 1/2 percentage points.

Not to worry. Engineers found the rail cars can handle the 150-foot-long section at the steeper grade after all.

"It was the biggest engineering feat of the whole job," said a thankful Ronald J. Hartman, MTA's administrator. "There was no clear way to go."

Passengers will recognize the Rebel Yell as the section of track between the North Avenue Mount Royal stations where the trains slow considerably. The cars can take the section at only about 15 mph, so the roller coaster effect is minimized.

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