Section 210.33 - Operation standards (switcher locomotives, load cell test stands, car coupling operations, and retarders)(a) Measurement on receiving property of the noise emission levels from switcher locomotives, load cell test stands, car coupling operations, and retarders shall be performed in accordance with the requirements of 40 CFR part 201 and § 210.25 of this part.(b) These sources shall be considered in noncompliance whenever the test measurement, minus the appropriate tolerance (§ 210.25 ), exceeds the noise emission levels prescribed in appendix A of this part.