About Train Horn
Train Horn is an independent reference site that aggregates publicly available data on train horns, the federal grade-crossing rule, US state-by-state vehicle codes, and the aftermarket category — built to be the resource that primary-source links every claim instead of paraphrasing.
What this site is
Most pages you find when researching train horns are either retailer product listings or short content-farm articles. We built Train Horn as a primary-source reference: every numeric claim, legal citation, and product spec on this site links back to the document where the information originated.
We are aggregators, not testers. We do not own a calibrated SPL meter; we do not run our own decibel readings. What we do is read the same primary documents you would — federal regulations, state vehicle codes, manufacturer data sheets, published acoustic studies — and present them in a structured, cross-linked, and fact-checked format with the source link on every claim.
Editorial methodology
Every page on this site is written against a documented standard. The five rules below are non-negotiable:
- Right source for the claim. For legal claims (state vehicle codes, federal regulations), we cite primary legal sources — Justia, FindLaw, official state legislature sites, eCFR, the Federal Register — never a commercial retailer's "is this legal in your state" marketing page. For product claims (decibels, PSI, dimensions, kit contents), we cite the manufacturer's product page, retailer product listings (HornBlasters, Kleinn, Wolo, BossHorn, Vevor, Vixen, etc.), and independent acoustic measurements where they exist. We label which kind of source each citation is.
- Verified vs. claimed output. Where a manufacturer or retailer publishes a decibel value, we cite it as the manufacturer/retailer claim. Where third parties (HornRating, independent SPL measurements published by enthusiasts, university acoustic studies) have measured the same horn, we cite both side by side. Manufacturer claims of 170 dB+ are flagged as physically inconsistent with the speed of sound through air.
- Every numeric claim is sourced. Every decibel value, price, PSI rating, and statutory limit on this site links back to the document where the number came from. We do not invent numbers, silently average competing claims, or repeat unsourced figures from other content sites.
- Update cadence. Reference pages (definitions, federal regulations) are reviewed quarterly. State legality pages are reviewed when a state amends the relevant vehicle code. Product pages are reviewed when the manufacturer or retailer updates pricing or specs. Each page shows a "Last reviewed" date — not a publish date — for transparency.
- Corrections policy. Errors of fact are corrected within 48 hours of being verified. Material corrections are noted with a struck-through original where the change affects a quoted spec or legal interpretation. Email [email protected] to report an error — please include a source link for the corrected information.
What we read
We aggregate from the following categories of public source material. We do not republish content; we summarize, cite, and link.
- Federal regulations
- Code of Federal Regulations (eCFR), Federal Register, Federal Railroad Administration train-horn rule, NIOSH and OSHA noise-exposure guidance
- State law
- Justia state-law mirrors, FindLaw, official state legislature sites, individual state vehicle codes (e.g. California Vehicle Code §§ 27000–27002)
- Manufacturer & retailer product documentation
- Product pages, data sheets, installation manuals, and warranty documents from Nathan AirChime, Leslie Controls, HornBlasters, Kleinn, Wolo, BossHorn, Vixen, Vevor, and other named manufacturers and aftermarket retailers — used for product specs (dB, PSI, dimensions, price), not for legal interpretations
- Independent acoustic measurements
- Published SPL readings from the HornRating community, university acoustic engineering papers, NTSB rail-grade-crossing reports, and verified hobbyist measurements with stated equipment and methodology
- Historical and reference works
- Railroad operating rule books (GCOR, NORAC), industry trade publications, and primary-source archival material on the steam-whistle to chord-horn transition
When we cite a number that has different values across sources (typical for aftermarket-horn dB output), we list each source's claim alongside the others rather than picking one and silently reporting it as fact.
Independence
Train Horn is editorial. We do not sell horns, do not run paid product placements, and do not accept money from manufacturers or retailers in exchange for review coverage. When we link out to a retailer or manufacturer, we link to whoever publishes the source document or sells the product — not to a single preferred vendor.
Where a product on this site is also sold by an affiliated retailer, we name the affiliation explicitly on the page in question rather than burying it.
Contact
- Editorial corrections & tips: [email protected]
- Press inquiries: [email protected]
- Reader feedback / general: contact form
Where to start
- Train Horn — main reference entry (definition, decibels, types, legality, install)
- State-by-state legality
- Aftermarket model reviews
- Install guides by vehicle and task
- Terminology glossary