Click here to write a Letter to the Editor. The Environmental Protection Agency issued guidelines to engine manufacturers governing the use of new technology to meet 2010 emission standards. It also said it will approve pollution rules governing railroad emissions in 2007.EPA issued guidelines for urea-injection systems on diesel engines in October, a move truck-engine manufacturers said was an important first step in the industry’s development of engines to meet the agency’s 2010 emission requirements.Urea injection is a process also known as selective catalytic reduction. After initially opposing SCR, EPA officials said they would not close the door on the use of the technology in new truck engines, and some engine manufacturers said they will use SCR to meet EPA’s 2010 emission rule.For the full story, see the Jan. 1 print edition of Transport Topics. Subscribe today.