Legal — By City
Train Horn Laws in San Diego California
San Diego is the southern terminus of the LOSSAN corridor — Coaster commuter, Amtrak Pacific Surfliner, and BNSF freight. Plus the MTS Trolley light-rail system. FRA grade-crossing horn rule applies to all LOSSAN freight / passenger crossings.
By Train Horn Editorial Published April 28, 2026
Disclaimer
Informational only — verify with the City of San Diego and FRA Quiet Zone Database.
Federal framework
Under 49 CFR § 222, every FRA-regulated locomotive must sound • • — • at 96–110 dB at every public highway-rail at-grade crossing. The MTS Trolley operates under a different regulatory regime (FTA + state) — Trolley horn use is more limited.
San Diego rail context
- NCTD Coaster — Oceanside–San Diego commuter, with terminus at San Diego Santa Fe Depot
- Amtrak Pacific Surfliner — terminus at San Diego (LOSSAN southern endpoint)
- BNSF freight — overnight freight on LOSSAN
- SDMTS Trolley — Blue, Green, Orange, Silver lines (light rail, separate regulatory regime)
- SDIY (San Diego & Imperial Valley Railroad) — short-line freight to Imperial Valley
- Pacific Imperial Railroad — eastern San Diego County (less active)
How to verify quiet-zone status
Vehicle train horn rules — California state law
See our California train horn laws.