40 C.F.R. § 1033 app A to Part 1033
(a) Locomotives were originally subject to Tier 0, Tier 1, and Tier 2 emission standards described in paragraph (b) of this appendix as follows:
(1) The Tier 0 and Tier 1 standards in paragraph (b) of this appendix applied instead of the Tier 0 and Tier 1 standards of § 1033.101 for locomotives manufactured and remanufactured before January 1, 2010. For example, a locomotive that was originally manufactured in 2004 and remanufactured on April 10, 2011, was subject to the original Tier 1 standards specified in paragraph (b) of this appendix and became subject to the Tier 1 standards of § 1033.101 when it was remanufactured on April 10, 2011.
(2) The Tier 2 standards in paragraph (b) of this appendix applied instead of the Tier 2 standards of § 1033.101 for locomotives manufactured and remanufactured before January 1, 2013.
(b) The following NOX and PM standards applied before the dates specified in paragraph (a) of this appendix:
Table 1 to Appendix A-Original Locomotive Emission Standards
| Type of standard | Year of original manufacture | Tier | Standards (g/bhp-hr) | ||
| NOX | PM-primary | PM-alternatea | |||
| Line-haul | 1973-1992 | Tier 0 | 9.5 | 0.60 | 0.30 |
| 1993-2004 | Tier 1 | 7.4 | 0.45 | 0.22 | |
| 2005-2011 | Tier 2 | 5.5 | 0.20 | 0.10 | |
| Switch | 1973-1992 | Tier 0 | 14.0 | 0.72 | 0.36 |
| 1993-2004 | Tier 1 | 11.0 | 0.54 | 0.27 | |
| 2005-2011 | Tier 2 | 8.1 | 0.24 | 0.12 | |
a Locomotives certified to the alternate PM standards are also subject to alternate CO standards of 10.0 for the line-haul cycle and 12.0 for the switch cycle.
(c) The original Tier 0, Tier 1, and Tier 2 standards for HC and CO emissions and smoke are the same standards identified in § 1033.101 .
40 C.F.R. 1033 app A to Part 1033