{"data":{"id":"us/49-cfr-299.313","jurisdiction":"us","citation":"49 CFR 299.313","heading":"Track geometry; performance based.","body":"(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:\nTable 1 to Paragraph (a)\nCarbody acceleration limits 1 2\nLateral vibration 3 Vertical vibration 3\n≤ 0.35 g peak-to-peak ≤ 0.45g peak-to-peak\n1 sec window 1 sec window\nexcluding peaks \u003c 50 msec excluding peaks \u003c 50 msec\n1 Carbody accelerations in the vertical and lateral directions shall be measured by accelerometers oriented and located in accordance with § 299.337(c)(3).\n2 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.\n3 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.\n(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.","path":["Title 49—Transportation","Subtitle B—Other Regulations Relating to Transportation","CHAPTER II—FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION","PART 299—TEXAS CENTRAL RAILROAD HIGH-SPEED RAIL SAFETY STANDARDS","Subpart C—Track Safety Standards"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-49.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:34Z","sha256":"1df5c7f0512926f60775f0b01e4c88a05248d287c66bc46aa9d81959ef8eb47a","source_id":"us-cfr","stale":true,"prev":"us/49-cfr-299.311","next":"us/49-cfr-299.315"},"notice":"GroundRules: Original legal text. Not legal advice."}