Inside Duke Medicine

30 years on the PRT

DUH’s PRT seems to run with pilot-less ease—but it takes a human touch.

Duke University Hospital’s PRT between South and North may seem to hum along with pilot-less, effortless ease.

But the story of the 30-year-old tram system is much more complicated than that, and starts with the fine behind-the-scenes work of Jimmy Mathews and Gary Burke. Read more in the following Inside Duke Medicine story by Mark Schreiner:

They were there before the beginning, and now they’ll be there after the end.

But let’s not get ahead of ourselves.

This story is about Jimmy Mathews and Gary Burke.

They work in a tidy shop in a lower level of Duke University Hospital. There, as they have for three decades, they and their colleagues keep the hospital’s unique PRT tram system going.

After 30 years, they say they are still impressed by the technology of the system, parts of which are similar to the machine that put Neil Armstrong and Buzz Aldrin on the moon in 1969, and whose full name is Personal Rapid Transit.

Mathews and Burke know that PRT’s departure is needed to make way for significant expansion projects, but they are a little sad to see it go.

“When Duke bought the PRT, they bought the best - we’re still using the original equipment,” Mathews said. “I suppose you could consider us original equipment, too.”

On Oct. 15, the service—at least the part between the North and South hospitals—will end. Expansion projects, including a major hospital addition, are being built where the PRT guideway is located.

When the projects are complete, North, South and the new addition will be connected by something that part of the medical center has never had, climate-controlled indoor walkways.

Keeping it going

Decades ago, the PRT’s maker, Otis Elevator Co., left the PRT business.

When parts wore out, when electronics needed repair, there was no catalog to order from, no help line to call.
Burke, an Appalachian State-trained electrician, has made himself an expert at electronics. In his spare time, he’s repaired the broken toys in the discount bin at Radio Shack and given them away as presents. He also credits a Duke colleague, the late John Tewksbury, with giving him critical training in electronics.
For the PRT, he’s fabricated whole computer chip panels, patiently re-soldering hundreds of tiny electronic connections.

“We’ve repaired, fixed and fabricated to keep it going,” said Mathews. “We have a higher performance rate - near 99 percent - than what was estimated when it was first built. The goal was 97 percent performance.”

The story of that long run of professionalism and craftsmanship began more than 30 years ago.
In the mid-1970s, Mathews and Burke were relatively new employees - electricians working for Medical Center Engineering & Operations.

One day, a supervisor came in and showed Burke a recent issue of Popular Mechanics. The cover story was about a new people-moving concept that wasn’t an elevator and wasn’t a train, but had elements of both.

“Then he looked at me and said, ‘Gary, you’re going to build it,’ ” he said.

The future, then

Burke and Mathews were sent with their families to Denver, where manufacturer Otis had its laboratories and factory.

Between skiing and seeing Pike’s Peak, they worked with engineers on the system they were designing to serve Duke Hospital’s planned North Division.

The PRT was required because not all hospital functions could be moved from the building that today is known as South into what became known as North. Patients and staff would have to be moved back and forth between the buildings.

Early medical center studies eliminated a moving sidewalk as a solution.

So, in a time before widespread use of the Internet or electronic medical records that could flash across the medical center in an instant, the PRT was cutting-edge technology.

Also, in 1979, there was the issue of a quarter-mile distance between buildings to consider.

But, the landscape will be very different when the expansion of Duke University Hospital and, potentially, a proposed cancer center are complete. Current plans foresee just a 90-foot gap between buildings that, unlike the present walkway, will be enclosed and climate-controlled.

When Otis announced it had made a $5.9 million deal with Duke for a futuristic “horizontal elevator” in the mid-1970s, the news was reported in newspapers big and small around the world.

By 1979, the PRT was being installed at the medical center. The first ride was taken in December 1979. The Associated Press told the world that Duke treated the first ride “as a major event: officials dispensed punch and had an employee chorus sing railroad songs.”

State transportation Secretary Tom Bradshaw was there and Duke Eye Center receptionist Jane Bindewald cut the ribbon.

How it works

Here’s how the PRT works: Specially-designed vehicles ride in concrete guideways. Rails on the guideways feed electricity into the vehicle. With that power, a blower pushes air through rubber skirts on the vehicle’s bottom. It rides on a cushion of air, like a hovercraft.

An additional system uses magnetic induction, pushing against an iron-and-aluminum bar in the guideway, to propel the vehicle forward.

Inside the vehicle, a pair of computers - this is the Space Age part - monitor operations and use data from sophisticated sensors to match speed and position against guide markers and its own programming. When the two computers agree, the machine moves forward.

The pilot-less vehicle hums as it carries staff, faculty, visitors and patients over the quarter-mile run from North to South. A trip takes about a minute. The system is monitored by a round-the-clock staff.

It’s not a perfect system. It doesn’t operate as well in rainy weather, and snow shuts it down completely, since the vehicles hover so close to the surface.

Even so, the well-made, redundant equipment has been so robust, Mathews said, there’s never been need to overhaul or renovate the system. It has run 24 hours a day since that first day in 1979.

Next steps

After 30 years with Duke, Mathews and Burke are staying. And they will continue to work on the PRT - particularly, the line that runs under Erwin Road between Duke North and Parking Garage II.

The talents of the PRT teams other members are still needed - they will continue to be employed with Duke in other positions.

The last three decades have been good, Burke said.

“I have a job where everyday I am continually challenged,” he said. “I have to learn new things, I have to solve problems - that’s what makes a good job.”

Mathews’ recently saw his youngest graduate from the University of North Carolina at Wilmington. “But we’re still here and we will keep it going,” Mathews said. “For as long as we’re needed.”

Read the previous story about the PRT closing here.