Regulations covering the emissions from diesel engines in locomotives have not kept pace with the emission limits placed on heavy-duty trucks, buses and non-road equipment. However, EPA has recently issued New Source Performance Standards (NSPS) for Tier 4 line haul and switcher locomotives.
A variety of technologies including zeolite SCR, active-regen DPF, ASC (ammonia slip catalyst) and engine modifications are being used to meet these stringent Tier 4 NOx and PM limits.
Johnson Matthey's CRT and SCRT systems are particularly suitable for these applications and have been gaining extensive field experience in HDD trucks. Johnson Matthey is one of the first companies to introduce Selective Catalytic Reduction (SCR) catalyst for HDD trucks in Europe and our ongoing R&D program will advance the technology for locomotive application.
The first CRT systems were fitted to DMUs (railcars) in the mid-1990s and the longest serving of these have now demonstrated 1.5m km of effective and trouble-free service. Experience shows that these systems are as effective in retrofit applications on rail as they are on road vehicles.
Johnson Matthey also has first hand experience of the application of exhaust after treatment systems to locomotives and track maintenance vehicles, including research into PM emission control from locomotives, including a major project at the Southwest Research Institute, San Antonio, Texas.
The US EPA's NSPS provides a model regulation for locomotives. Emissions standards for new engines have already been agreed upon by the European Union.