DART’s new fleet of smoother-riding, cleaner-running 40-foot buses is taking to the streets. The new fleet began service on January 28 and will replace the agency’s mix of diesel and liquefied natural gas buses by 2015. The 459 buses, running exclusively on compressed natural gas (CNG), will cut the agency’s annual fuel costs by nearly two-thirds by the end of 2015 and significantly limit harmful emissions.
The new buses are 40-foot models with a new low floor design for easier entry, larger windows for increased visibility, a wider aisle that allows greater flexibility with wheelchairs and mobility devices, interior cameras for safety, and has LED interior monitors located in the front and rear for displaying visual images, including next stop, rider alerts, passenger information and stop requests. DART plans to put approximately five new buses into service every week to replace the existing fleet.
The 30- and 40-foot buses mark the latest phase of DART’s clean transit fuels program. The $210 million contract with North American Bus Industries Inc. (NABI) of Anniston, Alabama, one of the nation’s largest CNG bus orders, will allow the agency to introduce heavy-duty buses to replace the current fleet of liquefied natural gas and clean diesel buses, which began service in 1998. The agency also built four CNG fueling stations at its bus and mobility management operations facilities.
DART’s new CNG buses come equipped with roof mounted CNG tanks. These tanks are located within a rooftop enclosure which is designed to enhance the aesthetics of the bus while also being easily accessible for routine inspections and maintenance. The buses utilize a bolt-on fuel tank cradle-structure, which mounts to the roof structure.
The CNG tanks are neck-mounted to the cradle, and the entire fuel storage network (including valves and plumbing) is concealed from street-level view with roof fairings.
Total capacity of the tanks is 19,992 standard cubic feet, with each bus fitted with six CNG 16-inch diameter cylinders.
(This article compiled using information from a DART press release)