Locomotives
Locomotive engines are significant contributors to air pollution in many of our nation's cities and ports. Although locomotive engines being produced today must meet relatively modest emission requirements set in 1997, they continue to emit large amounts of nitrogen oxides and particulate matter (PM), both of which contribute to serious public health problems.
In May 2004, as part of the Clean Air Nonroad Diesel Rule, EPA finalized new requirements for nonroad diesel fuel that will decrease the allowable levels of sulfur in fuel used in locomotives by 99 percent. These fuel improvements will create immediate and significant environmental and public health benefits by reducing PM from existing engines.
In March 2008, EPA finalized a three part program that will dramatically reduce emissions from diesel locomotives of all types -- line-haul, switch, and passenger rail. The rule will cut PM emissions from these engines by as much as 90 percent and NOx emissions by as much as 80 percent when fully implemented.
This final rule sets new emission standards for existing locomotives when they are remanufactured--to take effect as soon as certified systems are available, as early as 2008. The rule also sets Tier 3 emission standards for newly-built locomotives, provisions for clean switch locomotives, and idle reduction requirements for new and remanufactured locomotives. Finally, the rule establishes long-term, Tier 4, standards for newly-built engines based on the application of high-efficiency catalytic aftertreatment technology, beginning in 2015.
This page provides general and technical information on the locomotive rulemakings that affect railroads, locomotive manufacturers, and remanufacturers.
NOTE: You will need Adobe Acrobat Reader, available as a free download, to view some of the files on this page. See EPA's PDF page to learn more about PDF, and for a link to the free Acrobat Reader.
Regulations and Guidance
See the electronic Code of Federal Regulations (e-CFR) for the full text of current regulations that apply to locomotives. The documents related to the rulemaking that established these provisions are available below.
- Final Rule: Control of Emissions of Air Pollution from Locomotives and Marine Compression-Ignition Engines Less Than 30 Liters per Cylinder
(published May 6, 2008 and republished June 30, 2008)
- Fact Sheet: EPA Finalizes More Stringent Emissions Standards for Locomotive Engines and Marine Compression-Ignition Engines | PDF Version (5 pp, 144K, March 2008, EPA420-F-08-004)
- Final Rule (republished June 30, 2008)
- Pages 37095-37144 | PDF Version (50 pp, 1,063K)
- Pages 37145-37194 | PDF Version (50 pp, 1,246K)
- Pages 37195-37244 | PDF Version (50 pp, 917K)
- Pages 37245-37294 | PDF Version (50 pp, 1,253K)
- Pages 37295-37344 | PDF Version (50 pp, 1,260K)
- Pages 37345-37350 | PDF Version (6 pp, 157K)
- Final Rule (published May 6, 2008)
- Preamble and 40 CFR Parts 85-94 (Pages 25097-25146) | PDF Version (50 pp, 364K)
- Pages 25147-25196 | PDF Version (50 pp, 1,141K)
- Pages 25197-25246 | PDF Version (50 pp, 922K)
- Pages 25247-25296 | PDF Version (50 pp, 1,347K)
- Pages 25297-25346 | PDF Version (50 pp, 1,316K)
- Pages 25347-25352 | PDF Version (6 pp, 158K)
- Regulatory Impact Analysis (PDF) (739 pp, 10MB, May 2008, EPA420-R-08-001a)
- Summary and Analysis of Comments (PDF) (463 pp, 2.4MB, March 2008, EPA420-F-08-006) Instead of downloading the entire document, you can access the individual chapters of the Summary and Analysis of Comments.
- See the Proposed Rule (published April 3, 2007) and the Advance Notice of Proposed Rulemaking (published June 29, 2004) for the rules, fact sheets, and technical support documents.
- Final 2005 Technical Amendments – Procedures for Testing Highway and Nonroad Engines and Omnibus Technical Amendments (published July 13, 2005)
- Fact Sheet: Regulatory Announcement: Changed Test Procedures for Nonroad Engines and Heavy-Duty Highway Engines | PDF Version (4 pp, 134K, EPA420-F-05-036, July 2005)
- Final Rule : Entire Document | PDF Version (194 pp, 7.4MB)
- Preamble and 40 CFR Parts 85-94 (PDF), pages 40419-40462 (43 pp, 762K)
- 40 CFR Parts 1039, 1048, 1051, and 1068 (PDF), pages 40462-40516 (55 pp, 986K)
- 40 CFR Part 1065 (PDF), pages 40516-40612 (97 pp, 8.6MB)
- Technical Support Document and Summary & Analysis of Comments (PDF) (115 pp, 1.7MB, EPA420-R-05-008, June 2005)
- See Proposed Technical Amendments for the proposed rule, fact sheet, and technical support documents (published September 10, 2004).
- Idling Locomotives Fact Sheet: Control of Emissions from Idling Locomotives | PDF Version (4 pp, 98K, March 2008, EPA420-F-08-014)
- 1997 Locomotive Emissions Final Rulemaking (published December 17, 1997)
- Read First (2K, TXT)
- Final Rule published April 16, 1998 (consists of three separate files)
574K PDF,
466K PDF,
60K PDF and
317K TXT, 336K TXT, 55K TXT - Docket Listing (PDF) (61K)
- Summary Analysis of Comments (WP5 ZIP file) (135K)
- Regulatory Support Document (PDF) (3.9MB)
- RSD Data (WK3 file) (184K)
- RSD Appendices (PDF) (2.4MB)
- Fact Sheets:
- Requirements for Railroads Regarding Locomotive Exhaust Emission Standards (PDF) (94K)
- Applicability of Locomotive Emission Standards (PDF) (78K)
- Final Emission Standards for Locomotives (PDF) (19K)
- Environmental Benefits of Emission Standards for Locomotives (PDF) (39K)
- Federal Preemption of State and Local Standards for Locomotives (PDF) (11K)
- Emission Factors for Locomotives (PDF) (31K)
- See the Proposed Rule (published January 31, 1997).
- Future Nonroad Emission Reduction Credits for Locomotives (January 1995) (TXT) (7K)
Related Links:
- Compliance Fees
- Certification Data
- Federal Railroad Administration, U.S. Department of Transportation
- Clean Diesel Programs
- Nonroad Diesel Equipment
- Diesel Fuel
For more information, please email EPA's Assessment and Standards Division (asdinfo@epa.gov) or call the Assessment and Standards Division voicemail at 734-214-4636.