Denver’s “Train to the Plane” has an image problem.

The much-ballyhooed A Line, designed as a fast way to move passengers to and from downtown’s Union Station to Denver International Airport, has been plagued by glitches almost from the moment it opened on April 22, 2016.

Electrical outages. Crossing-gate malfunctions. Weather-related delays that contributed to an on-time performance that dipped as low as 40% during summer 2016.

It has not been the debut that the area’s Regional Transportation District hoped for – or expected – when the $1.2-billion project took to the rails after years of construction and months of testing.

(Click to enlarge) Denver's A Line connects downtown to the international airport. Naming rights were sold to the University of Colorado.The line, which serves eight stations and covers 23 miles between DIA and Union Station, with a usual travel time of about 37 minutes, has also endured problems with software – related to the system’s positive train control – that have now delayed the opening of a G Line that would connect downtown with areas on the northwest side of the Denver metro area.

Growing Pains

RTD officials warned there would be growing pains during at least the first year of the A Line’s operation, due to its new technology and the system’s complexity. The warnings proved prescient and have continued into the winter, and involved more than technology. Cold weather snapped rails in December during the first onset of freezing temperatures. The cold also contributed to broken lines on other parts of RTD’s commuter rail system.

Several components are involved in the operation of RTD’s rail lines, including the A Line. They include the overhead catenary system (OCS), or the overhead electrical lines that transmit electricity to the trains; traction power substations (TPSS), which convert the electricity to the proper voltage, current type and frequency for the trains; train signaling systems with relay houses; and communication houses.

Having so many systems involved with its operation underscores the challenges for transit engineers who worked to get the line up and running, and magnifies the challenges to keep the system operating as intended. It also has brought heightened scrutiny of the system as government officials and the public at large continue to express their frustration about its operation.

The A Line from downtown Denver to DIA, along with the system’s B Line to Denver’s northern suburbs and the not-yet-operating G Line are known collectively as the Eagle P3 project. Eagle P3 has been touted as the first system in the U.S. to have positive train control (PTC) aspects built in, as opposed to having those controls retrofitted into existing operations, according to RTD. The PTC systems kick in automatically to slow and stop trains when software senses a problem, such as a train traveling too fast or some other incident on the route.

(Click to enlarge.) Denver's ambitious commuter rail construction projects will last until mid-century.Federal transportation officials want rail operators to implement PTC technology ahead of a congressionally mandated Dec. 31, 2018 deadline. PTC uses digital radio communications, GPS, and fixed wayside signal systems to send and receive real-time data about the location, direction, and speed of trains.

Software Problems

An RTD spokesman said part of the problem with the A Line (and also with the B Line) is that the PTC software controlling crossing gates at intersections along the routes was designed using estimates to account for human behavior around trains. Real-world operations did not match those projections.

That means the software must be re-engineered to account for differences in how operators drive their train, and to account for the fact passengers sometimes need more time to get on and off the train. It also will take into account the differences in time it takes motorists to clear intersections before crossing gates can fully drop.

RTD has said it continues to calibrate the software as it receives more information about those factors. The agency said in a December 2016 presentation to federal railroad officials that after a software update it expects the on-time percentage of the A and B lines’ crossing gates should improve from 39% to 65%. The on-time percentage means the crossing gates will rise and fall within 10% of the intended time frame as a train approaches and then moves away.

The Federal Railroad Administration (FRA) has issued waivers allowing RTD to continue to operate the A and B lines as RTD works to resolve the crossing-gate problem. At present, RTD must station human flaggers at each crossing around the clock to ensure the safety of drivers and pedestrians near the crossings. FRA has said it will not allow the G Line to open until the problem is solved on the A and B lines.

The current 90-day waiver for continued operation expires Feb. 4. RTD has said it will apply for another waiver, and the FRA said it expects that to happen, but that the waivers were “never meant to be a long-term solution” for the situation.

RTD, along with contractor Denver Transit Partners (DTP), has said it expects software updates should be complete prior to the Feb. 4 waiver expiration, but that improvements to control systems and tracks could take another three months.

(According to its web site, DTP is comprised of a partnership between Fluor Enterprises, Inc. [a unit of Fluor Corp.]; Denver Rail [Eagle] Holdings, Inc., a unit of John Laing plc; and Aberdeen Infrastructure Investments [No 4] USA LLC, a unit of Aberdeen Global Infrastructure Partners LP. Other team members include Balfour Beatty Rail Inc., ACI, Ames Construction and HDR.)

Part of the software fix includes reducing the number of crossing gates the software communicates with along the route. The system was designed to “talk” to as many as six gates along a segment of the route; as a result a delay early in a segment becomes compounded at the sixth gate. The software now will be engineered to talk to just two or three gates, according to RTD.

RTD said it also will fix hardware that needs to be installed on a redundant safety control system, also designed to work with shorter segments of the train route. However, that fix will take longer to implement.

Lightning Strikes

Software and hardware problems can plague any new system, but weather-related outages likely were not expected when the A Line opened. A presumed lightning strike last May 24 caused a seven-hour shutdown of the line. RTD said the strike apparently severed an electrical wire, triggering the shutdown. Video from the day shows passengers being evacuated and walking along a bridge.

An email the following day from an RTD director said the agency had urged Denver Transit Partners to run a static wire above the OCS to shield the electrical wire from lightning. The RTD email said DTP “essentially refused our pleas with them” and “did not follow good industry practice with their particular design approach.”

A Line passengers evacuate a stalled train after a lightning strike damaged a power line. Credit: 9News.comRTD later referenced a consultant’s white paper that had said “historic lightning flash density is extremely high along the A Line.” Jeff Whiteman, a project engineer with the Eagle P3 project, wrote a summary of the white paper in which he said “A properly placed static wire could reduce direct lightning strikes by nearly 90 percent” along the line.

RTD has used a static wire on other parts of its light-rail system but general manager Dave Genova last fall said there is no industry requirement for its use. John Thompson, executive project director for Denver Transit Partners, said the system his group installed on the A Line is used internationally for commuter rail. Thompson told The Denver Post newspaper that “There is no technology currently that exists that can respond quickly enough to a direct hit by lightning.” He called the May 2016 outage “the consequence of rare and extraordinary circumstance.”

Disappointment

Denver-area government officials continue to say they have faith that RTD and its project partners have the engineering know-how to fix the problems and make the current situation a distant memory.

“I think the A Line, five years from now, we’re not even going to remember how frustrating it is,” Colorado Gov. John Hickenlooper told reporters in a recent meeting. But he noted he is “disappointed” in the performance of the line so far.

“I think everybody is disappointed,” he said. “The A Line was that great triumph that connected downtown Denver to the airport but also connects all parts of Denver to the airport. The public-private partnership and the ability of the partnership to respond to problems, it hasn’t been perfect.”