Environmetal Protection Agency Rules

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This page was last updated on August 11, 2024.

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Locomotive Noise Reduction

The following research was completed by Evan Werkema.

EPA noise regulations that went into effect in January 1980, see 40CFR201.12 paragraph b:

(b) No carrier subject to this regulation may operate any locomotive or combination of locomotives to which this regulation is applicable, and of which manufacture is completed after December 31, 1979, which produce A-weighted sound levels in excess of 90 dB when moving at any time or under any condition of grade, load, acceleration, or deceleration, when measured in accordance with the criteria specified in Subpart C of this part with fast meter response at 30 meters (100 feet) from the centerline of any section of track having less than a two (2) degree curve (or a radius of curvature greater than 873 meters (2,865 feet)).

https://www.ecfr.gov/current/title-40/chapter-I/subchapter-G/part-201/subpart-B

For locomotives built by General Electric, GE installed "sound baffles" covering the lower radiator intakes on locomotives built for four railroads. Evan Werkema wrote on August 11, 2024.

Apparently GE's throaty exhaust and noisy radiator fan ran afoul of those limits. So far as I know, the only GE's with the baffles were early B36-7's built new for AT&SF, Conrail, Southern Railway, and St. Louis Southwestern (SSW; Cotton Belt).

The fat stacks became standard on future GE power, but the baffles didn't. The Contemporary Diesel Spotters Guide speculated that GE developed a quieter radiator fan and no longer needed the baffles to comply with the noise requirements. All four roads that had B36-7's with the baffles eventually removed them. Santa Fe started taking theirs off about 1986-87.

On Union Pacific, the last 150 SD40-2s delivered in January through November 1980 (UP 3659-3808) were equipped with larger exhaust stacks that included internal sound baffles, and Q-style radiator fans that had been redesigned for quieter operation.

Locomotive Exhaust Emmissions

EPA Tier 0, Tier 1 and Tier 2 Requirements

The original federal regulations governing locomotive emissions became final in 1998, and went into effect on January 1, 2000, creating Tier 0, Tier 1, and Tier 2 emissions standards for railroad locomotives.

Union Pacific began receiving new SD70 locomotives beginning in December 2000 that were equipped to conform to the EPA Tier 1 emissions standards. These locomotives were equipped with larger radiators in a flared carbody to accommodate separate radiator cores for diesel engine jacket water and for aftercoolers. These locomotives were numbered UP 4635 and higher.

EPA Tier 3 and Tier 4 Requirements

The EPA issued new rulings affecting locomotive emissions in 2008. These rulings introduced significantly more restrictive Tier 3 and Tier 4 standards. The Tier 3 standards came into effect January 2012 and were met by advancing engine technology. Tier 4 standards become effective in 2015 and it was expected that these locomotives would require exhaust gas after treatment technologies such as Selective Catalytic Reduction (SCR). This newer regulation also includes more stringent emission standards for remanufactured Tier 0-2 locomotives.

EPA Tier 0+, Tier 1+ and 2+ Requirements

The EPA emissions standards were amended in 2008, and the designation was changed to Tier 0+, Tier 1+ and Tier 2+ to reflect the new stricter standards. These new standards were required on locomotives remanufactured after January 2010, and require that rebuilds of locomotives manufactured from 1973 to 1992 meet Tier 0+ standards. Locomotives built after 1993, which does not include any UP SD40-2s, have to meet the stricter Tier 1+ standards.

Diesel engine retrofit upgrades to conform with the updated emissions standards were from EMD, which issued an retrofit kit for both 710 and 645E engines, with the latter engine being what UP's SD40Ns have. These SD40N were rebuilt locomotives comply with the federal Tier 0+ requirements.

Beginning with the completion of UP 1550 on May 4, 2010, Union Pacific began modifying its refurbished SD40-2 locomotives with an updated and modern control system known as NEXSYS, supplied by ZTR Control Systems. Each locomotive was given a formal completion date, retaining its original SD40-2 model designation. With the completion of UP 1629 on July 8, 2011, UP began using a new model designation: SD40N, denoting the railroad's "SD40-2 Modernization Program" using the NexSys system.

Locomotives built before 1973 are exempt from any of these standards. Remanufactured locomotives originally built before 1993 must comply with Tier 0+. Remanufactured locomotives built after 1993 and before 2002 must also comply with Tier 0+. The exception is those locomotives that have an intake air cooling system, which must comply with Tier 1+. All locomotives built between 2002 and 2004 must comply with Tier 1+ standards when they are rebuilt. Locomotives built between 2005 and 2011 must comply with Tier 2+ when they are rebuilt. The new rules also require all new and remanufactured locomotives to be equipped with EPA certified idle reduction technology.

More Information

EPA Standards for Locomotive Emissions -- from the EPA Office of Transportation and Air Quality web site.

40 CFR 1033 - Control Of Emissions From Locomotives -- Code of Federal Regulations (CFR) Part 1033 requirements.

Federal Register for June 8, 2008, pages 37096-37350 (255 pages) -- Published rule that created the Tier 0+, Tier 1+, and Tier 2+ designations. (see page 37121)

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