(Portland, OR)  --  TriMet says it plans to use federal grant money to buy four new battery-electric buses to add to its fleet.  The Federal Transit Administration is providing TriMet a three-point-four-million-dollar grant that will enable the transit agency to purchase the 40-foot-long, Flyer XE40 Xcelsior buses, which are designed to reduce emissions and greenhouse gases.  The buses are expected to go into service in 2018.