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49 CFR 210

The noise limit that blocks American high-speed rail was set from measurements of trains running before 1976, and the FRA has proposed an alternative at 96 decibels

Money & World
The Editorial Team ·
A close monochrome photograph of acoustic absorber foam, its regular egg-crate ridges running away from the camera in dark grey rows that catch a raking light along their crests and fall into shadow between.
Photo: Guillaume Meurice / Pexels

Nothing in the United States runs faster than 150 miles an hour.

The Federal Railroad Administration says so in the second paragraph of a proposal it filed on Friday, and the sentence is the point of the whole document. The noise limits American railroads must meet were built from Environmental Protection Agency measurements of locomotives and railcars operating before 1976, when the fastest a train was allowed to go was 110 mph. Those limits are 90 decibels for a locomotive and 93 for a railcar.

Above about 160 mph, air becomes the loudest thing on a train. The agency writes that the aerodynamic noise is impractical or impossible to avoid, which means the old numbers do not merely constrain high-speed rail in the United States. They prevent it.

What Congress did, and when

The fix was authorised almost five years ago. Section 22423 of the infrastructure act signed in November 2021 amended the Noise Control Act to let the Transportation Department write standards for trains above 160 mph, in consultation with the EPA, and left the existing standards in place below that speed.

Friday is when the proposal to use that authority appeared.

The number

The alternative standard is an equivalent sound level of 96 dB(A) across a train pass-by, referenced to 160 mph. That reads louder than the rules it sits beside, and the agency is careful about why: it is measured at 25 feet rather than 100, and it is a different metric.

Faster trains get more room, by formula. Normalise the measurement back to 160 mph, subtract fifty times the log of the speed ratio, and compare. At 220 mph the ceiling works out at roughly 103 dB(A). Past 220 the formula stops, and anything faster goes through a special approval process instead.

The European specification for electric multiple units up to 155 mph caps at 95 dB(A), which the agency normalises to 96 for the purposes of this rule. It says it cannot adopt the European standard wholesale but invites comment on doing so.

None of it is compulsory. A railroad can keep testing against the 1970s limits at any speed it likes.

The economics are small on both sides. Over 30 years the agency puts the cost of the rule at $105,462 in present value terms, against $65.9m of benefits, which is $8,499 a year in testing costs and $5.4m a year saved by not having to quieten trainsets that were never loud in the way the old rule assumes.

The document: Federal Railroad Administration, Department of Transportation, High-Speed Train Noise Emission Standards, notice of proposed rulemaking and request for comments, 49 CFR part 210, Docket No. FRA-2025-0786, Notice No. 1, RIN 2130-AC83, FR document 2026-15724, filed for public inspection on 31 July 2026 at 8:45 a.m. Eastern with a stated publication date of 3 August 2026. The complete public inspection text was downloaded and read here; no fetch-tool summary was relied on and every figure, citation and quotation below was matched against the document. The notice states that comments are due 60 days after publication and that comments received later will be considered to the extent practicable. On the current position it states, verbatim, 'Currently, no trains operate in the United States at speeds above 160 mph, and the highest-speed trains now operate at a maximum of 150 mph.' It states that the existing noise emission standards under 40 CFR part 201 'are based on empirical data from EPA studies of locomotives and railcars operating before 1976', citing 41 FR 2184 of 14 January 1976, and that 'At the time, the maximum allowable train speed under FRA regulations was 110 mph.' It states that EPA set limits of 90 dB(A) for locomotives manufactured after 31 December 1979, citing 40 CFR 201.12(b), and that EPA found the upper range for railcar noise at 60 mph to be approximately 93 dB(A), which was set as the maximum for all operations. It states that 'Because certain levels of aerodynamic noise are impractical or impossible to avoid for train operations that exceed 160 mph, existing rail noise emission regulations would prevent full utilization of such operations in the United States.' On authority it states that section 22423 of the Infrastructure Investment and Jobs Act, Pub. L. No. 117-58, 135 Stat. 429, signed into law on 15 November 2021, amended section 17 of the Noise Control Act at 42 U.S.C. 4916 to permit the Department of Transportation, in consultation with EPA, to prescribe noise emission standards for trains operating above 160 mph, and that the existing EPA standards continue to govern at speeds not exceeding 160 mph. On the proposal itself, section 210.43 as proposed establishes 'a baseline equivalent sound level of 96 dB(A) for the duration of the train pass-by for a speed of 160 mph'; the regulatory text provides that Leq during pass-by at maximum operating speed, normalised to 160 mph, 'shall not exceed 96 dB(A)', with the normalisation given as Leq(160 mph) = Leq(Vmax) minus 50 times log(Vmax divided by 160 mph). The notice states that the 96 dB(A) figure, 'though numerically higher than the prescribed maximum sound level standard in part 201 of 90 dB(A) for locomotives and 93 dB(A) for railcars, reflects measurement from 25 ft rather than the part 201 measurement distance of 100 ft, and differences in the pass-by metric'. It states that under the proposed standard the allowable limit rises with speed and that 'At the maximum operating speed under the proposed standard (220 mph), the limit would be approximately 103 dB(A)'; that FRA is not proposing to extend the adjustment formula beyond 220 mph; and that operations above 220 mph would instead go through a special approval process in subpart D. It states that the alternative standard is optional, that 'No railroad would be required to avail itself of the alternatives proposed in this NPRM', and that existing standards remain available for demonstrating compliance at higher speeds. On the European comparison it states that EU noise emissions for multiple-unit electric trains at speeds up to 250 km/h, given as 155 mph, are capped at 95 dB(A), and that as adapted and normalised for this rule from the Noise Technical Specifications for Interoperability that value is 96 dB(A). Table ES-1, over a 30-year period of analysis in 2024 dollars, gives present value costs of $105,462 and benefits of $65,947,718 at a 7 percent discount rate, for net benefits of $65,842,257; at 3 percent the figures are $178,230, $100,525,866 and $100,347,636; annualised at 7 percent they are $8,499, $5,400,150 and $5,391,651. The notice is issued under authority at 42 U.S.C. 4916 delegated in 49 CFR 1.89 and signed by David A. Fink, Administrator..

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