Metro may buy hybrid buses to run in tunnel Diesel-electric coaches would be less polluting than dual-powered rigs Tuesday, December 4, 2001

By George Foster

Seattle Post-Intelligencer Reporter Metro is expecting to replace its troubled fleet of 236 dual-powered buses with hybrid diesel-electric coaches in the Downtown Transit Tunnel by 2004, once again going to a new technology for operating underground. Using a smaller diesel internal combustion engine in concert with a powerful battery pack, the hybrid is capable of reducing fuel consumption by 40 percent, as well as cutting down on hydrocarbon particulates and nitrous oxide emissions. The current, dual-powered buses operate on electricity or diesel power, not both at the same time like the hybrid. The technology is similar to that in the hybrid cars on the market -- the Toyota Prius and the Honda Insight -- but on a larger scale. A 40-foot demonstration hybrid provided by Allison Transmission was taken on trial runs around the Seattle area by Metro and Sound Transit yesterday and over the weekend. Jim Boon, Metro's vehicle maintenance manager, said it outperformed its diesel counterparts with speeds of more than 50 mph on long hills. But fuel efficiency and performance come at a price -- about $600,000 for a 60-foot articulated hybrid, Metro general manager Rick Walsh said yesterday. So far, there have not been many in production in this country. New York City has the largest fleet of hybrids, about 125. Two are being used by an Orange County, Calif., transit agency. Walsh added that King County plans to put one of these buses in trial service starting this spring. It will be tested on the cities tougher routes, including the tunnel. Sound Transit is expected to buy a similar hybrid by this summer, then test it out on its No. 550 express route between Bellevue and downtown tunnel, according to Fred Chun, that agency's hybrid project manager. The hybrids are seen as good candidates for operating in the downtown tunnel in conjunction with light rail. One reason is that unlike the hybrid, the present dual-powered Breda buses transfer to overhead electric power once they approach the tunnel. Separate overhead wiring, called catenary, must be installed to operate the Link light-rail trains in the tunnel. A Sound Transit evaluation of joined bus-train operations in the tunnel concluded the hybrids "would eliminate the need to operate tunnel buses that use trolley poles and would increase the operating flexibility and reliability in the transit tunnel." While in the tunnel, the 230-horsepower diesel engine would idle at about 800 rpm while the bus would be propelled by battery. Asked if the idling engine would produce enough emissions to cause air-pollution problems, Boon said "that's the part we are working out." He added that the fuel to be burned is a low sulfur diesel that will meet the Environmental Protection Agency's standards due to go into effect in 2007. That is the same year Sound Transit expects to begin converting the downtown tunnel for use by light rail. The Bredas are approaching 12 years old and "are kind of problematic," Boon said. "They have seven computers and a lot of circuit boards," he added. Also, obtaining parts can present a problem. "There are 236 Bredas in the world, and they are all here," he said. "They are not like a Chevy Biscayne." The rarity of dual-powered buses, Boon explained, is that there are few bus tunnels of any length in the world. The Italian-made Bredas were plagued with problems not long after they arrived from Florence in 1990 and 1991. Costing $430,000 in 1988 dollars, the parts also proved to be expensive. Breda charged $258 for an oil filter that could be bought locally for $4. A Breda radiator costing Metro $6,292 could have been bought in Seattle for $742. -------------------------------------------------------------------------------- P-I reporter George Foster can be reached at 206-448-8341 or georgefoster@seattlepi.com