49 CFR 299.313 - Track geometry; performance based.

Regulations last checked for updates: Feb 08, 2026

Title 49 - Transportation last revised: Feb 03, 2026

View all text of Subpart C [§ 299.301 - § 299.357]

§ 299.313 - Track geometry; performance based.

(a) For all track of Class H4 and above, vibration in the lateral and vertical directions measured on the carbody of a vehicle representative of the service fleet traveling at a speed no less than 10 km/h (6.2 mph) below the maximum speed permitted for the class of track, shall not exceed the limits prescribed in the following table:

Table 1 to Paragraph (a)

Carbody acceleration limits 1 2
Lateral vibration ³	Vertical vibration ³
≤ 0.35 g peak-to-peak	≤ 0.45g peak-to-peak
1 sec window	1 sec window
excluding peaks < 50 msec	excluding peaks < 50 msec

¹ Carbody accelerations in the vertical and lateral directions shall be measured by accelerometers oriented and located in accordance with § 299.337(c)(3).

² Acceleration measurements shall be processed through an LPF with a minimum cut-off frequency of 10 Hz. The sample rate for acceleration data shall be at least 200 samples per second.

³ Peak-to-peak accelerations shall be measured as the algebraic difference between the two extreme values of measured acceleration in any 1-second time period, excluding any peak lasting less than 50 milliseconds.

(b) If the carbody acceleration requirements are not met on a segment of track, the segment of track is to be reclassified to the next lower Class of track for which it does meet the requirements of this part.

authority: 49 U.S.C. 20103,20107,20133,20141,20302,20306,20701,21301,21304; 28 U.S.C. 2461,note; and 49 CFR 1.89

source: 85 FR 69731, Nov. 3, 2020, unless otherwise noted.

cite as: 49 CFR 299.313