United States
   Environmental Protector
Office of Transportation
and Air quality
May 2004
                  Clean Diesel Program for
                  Locomotives and  Marine Engines
                  The U.S. Environmental Protection Agency (EPA) is inviting comment
                  from all interested parties on a plan to propose more stringent emission
                  standards and other provisions for new and existing locomotives, and
                  new marine diesel engines. EPA is issuing an advance notice of
                  proposed rulemaking (ANPRM) to gather information and determine
                  how to proceed.
                  Engines Addressed in the ANPRM
      Locomotives  EPA is considering more protective standards for new and existing
                  locomotives. This approach would address the long service life of loco-
                  motive engines.

      Marine      EPA is considering standards for new marine diesel engines with per
      Diesel       cylinder displacement below 30 liters. The standards would apply to
      Enginies     marine diesel engines used in all applications: commercial (excluding
                  ocean vessels), recreational, and auxiliary. They would also apply to
                  engines at or below 37 kW, which were previously included in the non-
                  road standards.

Exhaust Emission Standards
EPA is considering emission standards modeled after our 2007/2010
clean highway and nonroad diesel engine program, with an emphasis on
achieving large reductions in PM emissions as early as possible through
the use of advanced emission control technology. These  locomotive and
marine standards, which could apply as early as 2011, would be based
on the application of high-efficiency catalytic aftertreatment enabled by
the availability of clean diesel fuel with a sulfur content  capped at 15
parts per million (ppm). The low-sulfur fuel is already being produced in
some U.S. markets, and refiners will be required to produce ultra-low
sulfur fuel for locomotive and marine engines in 2012. EPA had origi-
nally proposed a less stringent fuel standard of 500 ppm.

In EPA's Clean Diesel Truck and Bus Program and Clean Air Nonroad
Diesel Program, EPA estimated that NOx and PM emissions could be
reduced by 90 percent. EPA expects that similar levels of NOx and PM
reductions could be achieved by applying similar technologies to  loco-
motives and marine diesel engines.

In addition to standards for new engines, EPA is interested in ideas for
voluntary provisions and initiatives that could encourage cleaner engines
and retrofits, or accelerate replacement of existing engines.
Locomotive and Marine Diesel Engines Emissions
Need to be Reduced
Locomotive and marine diesel engines are significant contributors to air
pollution in many of our nation's cities and ports. Locomotive and
marine diesel engines produced today are required to meet relatively
modest emission standards. This means that they continue to emit large
amounts of nitrogen oxides (NOx) and particulate matter (PM), which
contribute to serious public health problems. The relative contribution of
these diesel engines is expected to grow due to the expected future
growth in the use of these engines. By 2030, EPA estimates that, without
new controls, locomotives and marine diesel engines will contribute
about 27 percent of mobile source NOx and 45 percent of mobile source
fine diesel parti culate matter (PM25) emissions.

Millions of Americans continue to live in areas with unhealthy air
quality that may endanger public health and the environment. Because
of this, federal, state, and local governments are  working to bring ozone

and particulate levels into compliance with the new more protective
health standards for ozone and particulate matter. The reductions EPA is
considering in this advance notice of proposed rulemaking (ANPRM)
will play a critical part in improving the air quality for states and local

Exhaust from diesel engines contributes to unhealthy concentrations of
fine particles and ozone which are linked to serious problems, including
premature death, increased risk of lung cancer, heart disease, aggravated
asthma and other respiratory conditions. In addition, PM, NOx, and
ozone adversely affect the environment in various ways including
visibility impairment, crop damage, and acid rain.
Public  Participation Opportunities
EPA welcomes comments on this ANPRM. For instructions on submit-
ting written comments, please see the Federal Register notice. It is
available from the EPA Air Docket by calling 202-566-1742;  please
refer to Docket No. OAR-2003-0190.

Information is also available at:


You can also contact EPA at:

     U.S. Environmental Protection Agency
     Assessment and Standards Division
     2000 Traverwood Drive
     Ann Arbor, MI 48105
     Voicemail: (734)214-4636
     E-mail: asdinfo@epa.gov