Nathan K5LA Train Horn Sound
The 5-chime B major 6th chord that defines modern North American freight. Installed on 90%+ of U.S. locomotives.
Nathan K5LA train horn — royalty-free CC0 sample (BigSoundBank)
Download MP3 ↓
What it sounds like
The K5LA is a 5-chime locomotive horn playing a B major 6th chord. The five bells produce these notes simultaneously:
- D♯3 (~311 Hz) — lowest bell, sets the chord fundamental
- F♯3 (~370 Hz) — minor third above the root
- G♯3 (~415 Hz) — sixth interval, gives the chord its bright voice
- B3 (~494 Hz) — fifth, fills the chord
- D♯4 (~622 Hz) — octave of the lowest, top of the chord
The interval pattern (D♯, F♯, G♯, B, D♯) is technically a B major 6th chord spread over two octaves — bright, sustained, and instantly recognizable. Hear it in our interactive train horn soundboard.
Where to listen and download
- Train Horn Hub interactive soundboard — synthesized K5LA chord, click-to-play
- YouTube — K5LA recordings (search results: thousands of railfan videos)
- Freesound.org — K5LA samples (Creative Commons licensed)
- Zedge — K5LA ringtones
For royalty-free MP3 downloads see /sounds/mp3-downloads/. For ringtones see /sounds/ringtones/.
What locomotives carry the K5LA?
The K5LA is the standard horn on virtually every modern North American Class I locomotive. Common installations:
- BNSF — fleet-wide K5LA standard on GE ES44 / SD70 series
- Union Pacific — K5LA on EMD SD70Ace, GE ET44AC fleet
- CSX — K5LA standard with P-series holdouts on legacy SD40-2 units
- Norfolk Southern — K5LA fleet-wide
- Amtrak — K5LA on most P42DC / Siemens Charger units
- Canadian Pacific / Canadian National — K5LA standard
Per Nathan AirChime, the company supplies 90%+ of U.S. locomotive horns. The K5LA is their flagship 5-chime model. See our K5LA glossary entry for technical specs.
K5LA vs. K5 vs. K3LA
- K5LA — 5 chimes, B major 6th, designed for the FRA 96–110 dB grade-crossing standard. Modern.
- K5 (predecessor) — 5 chimes, slightly different note layout, mostly retired but still in service on older fleets. K5 sound page.
- K3LA — 3 chimes (D♯/G♯/D♯ subset of the K5LA), used on smaller passenger units and short-line freight. K3LA sound page.
Audio character details
- Output: 149.4 dB measured at the source per FRA / Nathan AirChime testing
- FRA grade-crossing: Compliant with the 96–110 dB at 100 ft requirement (49 CFR § 222)
- Chord character: Major 6th gives a bright, "open" voice vs. minor 7♭5 of the K5HL (deeper, more dissonant)
- Sustained tone: All 5 bells fire simultaneously and sustain — not a sequenced chord
- Doppler shift: Audible pitch rise/fall as a moving locomotive passes a fixed listener
Aftermarket K5LA replicas
Several manufacturers sell K5LA-replica train horns for vehicle install:
Related sounds
Sources
- Nathan AirChime — manufacturer site (K5LA market dominance)
- Wikipedia — Nathan Manufacturing (chord configuration, fleet history)
- 49 CFR § 222 — FRA train horn rule (96–110 dB at 100 ft requirement)
- K5LA glossary entry (this site)
- Interactive soundboard (this site, synthesized chord)