The Birth Of An Automatic People Mover


One of the 29 vehicles in the Dulles fleet


From 2003 until late 2010 I worked on the construction management team that helped Washington Dulles International Airport (IAD) implement a new Automatic People Mover (APM) system. APMs are driverless vehicle systems and can be compared to horizontal elevators. APMs are in operation in about 25 US airports including Atlanta, Dallas, Denver, Las Vegas, Orlando, Tampa, San Francisco, and others. There are quite a few operating internationally such as in Mardrid’s Barrajas Airport.

So APMs are nothing new, but the trick at Dulles was to construct not only the APM system, but three new passenger terminals, and massively add on to the existing Main Terminal, without impacting daily airport operations. Good trick if you can pull it off, and we did.

The photo shows one of the 29 APM vehicles in the fleet.



One car per flatbed


IAD received the APMs in four different shipments from the manufacturer, Mitsubishi Heavy Industries (MHI) in Mihara, Japan, beginning in 2007. Since we were a couple of years away from Testing and Commissioning at that point, we really couldn’t play with the cars.

This photo shows a car arriving at the IAD Vehicle Maintenance Facility (VMF) on a flatbed trailer. The cars made their journey from Japan, through the Panama Canal, around Florida, and up to the Port of Baltimore where they were offloaded from ships onto trailers, and then trucked down I-95 to Dulles.



A good shot of the 40-ton crane


Mitsubushi Heavy had built a set of lifting devices and spreader bars that made removing the vehicles from the trailers a rather simple procedure. It took only a couple of hours to offload the six or so vehicles and tuck them away into the VMF.



Spin to win


One thing that I learned on this job was that there was no replacement for competent riggers, the guys with the mobile cranes. They make transfers such as this very unexciting and routine, just as it should be.

This shot shows the basic vehicle-two axles, four rubber tires, and two 100 hp electric traction motors. Similar MHI vehicles were also being installed in the Miami and Atlanta airports during this time. The major differences from the Miami and Atlanta vehicles was that the Dulles cars were designed to run as single cars if need be, whereas the Miami and Atlanta vehicles were designed to be run as “married pairs”, that is, the minimum consist on those systems was two cars. The IAD system currently runs three car trains, with the possibility to expand to four cars. Four cars is the max since station platforms and station doors won’t accommodate longer trains.



Ready to hit the ground


The paint scheme for the Dulles cars was suggested by one of the the architectural firms responsible for one of the three new passenger stations at the airport. I called it the “harlequin scheme”. Thankfully passengers don’t have much opportunity to see the cars as they come into the stations. My job was to manage the process of developing the paint scheme, not to design it. That’s not to say I didn’t attempt to slip my own ideas in, one of which was to paint each vehicle a different color. The extremely conservative engineers at IAD accepted this concept as they would a turd in a punch bowl. As you can see, my concept didn’t find wide acceptance.



The Dulles cars have steering


Once on the ground, the cars were aligned with guide rails to bring them into the VMF.

The tires are Michelins found on semis these days replacing dual drive wheels. Inflation pressure was 110 psi. Mandatory replacement life was 75,000 miles. At this mileage the tires still looked great, but having one crap out in service was not an acceptable eventuality.



Interior of the Vehicle Maintenance Facility


Each car was then dragged into the VMF to await testing and commissioning.


08 Chainage Map

Chainage map of the Dulles APM system


This is what the Dulles APM system map looks like. It’s about 2.5 miles long. The VMF is on the south end at the end of the spur tunnel.

Tier 3 is a placeholder station. It’s empty with no station platform doors, air conditioning, or other operational equipment.

Tier 2 is the eastern end of the United concourse. The concourse is about a mile long so if you if your flight is from the western end of the concourse, you will want to take a Mobile Lounge from the Main Terminal. United cheaped out during the construction phase and canceled the new Tier 2 concourse. Tier 2 remains a third world airport facility.

Tier 1 West is essentially Delta with a number of international carriers such as Emirates, ANA, Air France, and British Airways. Tier 1 East are a lot of commuter gates.

Main Terminal is the domain of the TSA and is the entry point to the APM system. No one gets to ride the APM without having gone through TSA security. In airport lingo, the APM system is “airside”.



Car interior


This is what the interior of an APM looks like, specifically that of one in service at Dulles. Mainly standee room with four seats at both ends of the car. Trip times between stations is minimal. The top speed of the Dulles APM is 43 mph which can be reached quickly. Hang on, the g-forces on acceleration or braking (yeah, at the risk of being pleonastic, acceleration is the change of the rate of speed) can be unsettling.

One of my main jobs on the project was to chair the Safety Committee. I was not a safety professional, but I found that this  job was one of educating the fire and police departments in what they might encounter dealing with the APM system under extreme conditions. More difficult was the Maintenance Department that wanted access to the APM tunnel during operating hours to change light bulbs. I never was able to convince them that they didn’t want to be in the tunnel with live 750V DC power. Nasty stuff. Plus driverless vehicles have no eyes and are insensitive anything in the guideway that shouldn’t be there.


Flaming Tire of Death [Converted]

Apocalypse Now

One of the Safety Committee members continually stymied discussion and problem resolution by citing a study done by one of the APM System consultants that hypothesized that if one of the tires on the APM were to catch fire, all hell would break loose. Her phobia was a buzzkill on a number of safety studies. It led me to design this graphic, which a number of committee members found to be  apropos.

I finally assigned one of our Safety Committee members to do a risk assessment study for the probability (this crap was way beyond my expertise, or interest, but I learned, maybe too late, that my fellow committee members could be relied upon) that a tire would catch fire as per MIL 882. His study indicated that we could expect a tire fire every 11 billion years. Case closed.

I thought that the logo was pretty cool. It was made into a T-shirt which I never got. Bummer.