The U.S. passenger rail industry posted a strong ridership increase in 2005, partially due to motorists parking their cars and boarding trains in the face of record high gasoline prices.
To take full advantage of this burgeoning interest in rail transportation, transit systems need to ensure they provide a service level that satisfies both existing and new customers. Key components of this customer service are on-time performance and frequency of service.
These components are being addressed by several transit properties, basically by modifying their signaling systems. Here are some examples of what transit systems are doing to ensure timely service, shorten headways and bolster passenger safety.
SkyTrain’s CBTC success
In Vancouver, British Columbia, the automated rail system called SkyTrain can squeeze down its headways from 108 seconds during peak periods to 90 seconds during special events, says Mike Richard, vice president of operations for the British Columbia Rapid Transit Co., which operates the system for the Greater Vancouver Transportation Authority.
What allows the SkyTrain to run such tight headways is its SelTrac S40 communication-based train control (CBTC) system, which was designed by Alcatel. “In our view, the SelTrac system has been phenomenal,” Richard says. “It’s been the safest mode of operation. We’re into our 21st year, and we’ve had zero operating incidents with automated train control. And we’re basically able to recover most, if not all, of our direct operating costs from the farebox because we have no need for train drivers. We staff our 34 stations and our 55 trains during the rush-hour with essentially 36 people.”
The SkyTrain system uses the 55 trains (210 cars) along 31 route miles with a daily ridership of 210,000. And this ridership, Richard adds, is increasing, especially during non-peak hours. During special events such as the international fireworks competition held every summer in Vancouver, SkyTrain is operating all 55 trains at 90-second headways for three to three-and-a-half hours. The only limit on the headways, he says, is the amount of time customers hold open the doors.
The automated train control system was upgraded during a $1 billion SkyTrain expansion that doubled the route length and added 12 stations. The extension, called the Millennium Line, opened in 2002. SkyTrain is now the longest driverless system in the world and maintains one of the lowest operating costs in the industry. Although Richard says he’s “quite happy” about the existing CBTC system, he says another upgrade could be in offing in the next five years or so. Specifically, the upgrade would create a graphical user interface that would consolidate the functions so that they could be monitored from a single terminal.
Richard says the transit agency considered installing a redundant wayside system during project planning in the early 1980s, when the CBTC technology still inspired some doubt, but decided against it. “Somebody had the guts to say, ‘No, we’re going to make this work,’ and we’ve never had to fall back,” he says. “We’ve learned it and mastered it, and the system has far outperformed the expectations.”
TriMet’s MAX light rail line in Portland, Ore., operates along 44 route miles with 105 cars. The system is limited to two-car trains due to 200-foot blocks in downtown Portland. Recent improvements to the signaling system have added flexibility to scheduling, reduced headways and increased safety.
John Griffiths, TriMet’s manager of rail operations planning, says before the Yellow line was opened in 2004, the agency added blocks and wayside signals east of the new junction with the Yellow line at Rose Quarter to Gateway (see map) to allow two-minute scheduled headways approaching and leaving the junction east and westbound.
The system uses automatic block signals (ABS) with automatic train stop. “Our design criteria for new lines require the ABS system to allow for three-minute scheduled headways,” Griffiths says.
“We also installed speed zones to enforce the slowing of trains approaching Gateway that have routes through a common interlocking,” Griffiths adds. “This allows these trains to approach each other safely, closer in time.”
Bob Banks, TriMet’s signal engineer, says a light rail system typically does not set up well for CBTC. “You’re moving in and out of different right-of-way systems, such as exclusive, semi-exclusive and mixed use,” he says. “An operator might forget to turn on the control system as the train is going in and out of different rights-of-way, creating the potential for an accident.”
Banks says it would cost approximately $100,000 per vehicle to convert from a wayside system to a communications-based system. “A wayside system with automatic train stops was the least expensive way to get us positive train control,” he says.
Union Switch and Signal (US&S) has been the prime contractor on TriMet’s rail signaling projects. Banks says he’s been “very pleased” with the support provided by US&S.
Helping the agency with the performance specifications has been LTK Engineering Services. “It’s not rocket science, but it’s a lot of work,” says Bob Abbott, senior engineer at LTK. “These tightened headways can help to carry more people without compromising safety.”
Reliability, plus cost savings
In Baltimore, the Maryland Transit Administration recently completed a double-tracking project that adds nearly 10 miles of track to the 29-mile light rail system. The project lasted about three and a half years and was capped by a grand reopening on March 27.
One of the changes made to the rail line during the construction of the additional tracks was a signaling modification that improves reliability, allows routine maintenance to be conducted without interrupting service and helps to reduce headways.
The engineering of the signaling system was handled by General Electric Transportation Services (GETS). Phil Beauchamp, project manager for GETS, says the signal modification performed during the double-tracking project involved the installation of an onboard computer subsystem and a wayside automatic train protection system, combined with the addition of software-based technology called train stop emulation that interfaces between the two. “With train stop emulation, if a train overruns a red wayside signal, the emulation system stops the train regardless of what the operator might try to do,” he says.
Beauchamp says the onboard computer system, called Ultracab II, monitors the actions of the operator. “When the operator is approaching an unsafe speed or an unsafe point in the railroad, it initiates propulsion or braking, whatever’s required to maintain the safest distance and the shortest distance while still being safe,” he explains.
Previously, the MTA was using a relay-based automatic block system, which requires more equipment than the current system. Beauchamp says GETS’ software-based approach, coupled with its wayside platform, allowed engineers to eliminate a substantial amount of trackside control equipment and wiring, which reduced maintenance and project costs and increased system reliability. “It was a win-win situation all the way around,” he says.