40 CFR § 1033.410 - In-use test procedure.
(a) You must test the complete locomotives; you may not test engines that are not installed in locomotives at the time of testing.
(b) Test the locomotive according to the test procedures outlined in subpart F of this part, except as provided in this section.
(c) Use the same test procedures for in-use testing as were used for certification, except for cases in which certification testing was not conducted with a locomotive, but with a development engine or other engine. In such cases, we will specify deviations from the certification test procedures as appropriate. We may allow or require other alternate procedures, with advance approval.
(d) Set all adjustable locomotive or engine parameters to values or positions that are within the range specified in the certificate of conformity. We may require you to set these parameters to specific values.
(e) We may waive a portion of the applicable test procedure that is not necessary to determine in-use compliance.