Nathan K5 Train Horn Sound
The original 5-chime that preceded the K5LA. Slightly different note voicing, mostly retired but still in service on older locomotives.
Nathan K5 train horn — royalty-free CC0 sample (BigSoundBank)
Download MP3 ↓
What it is
The Nathan AirChime K5 is the predecessor to the K5LA. Same 5-chime architecture, same physics — but with a different note voicing. The K5 typically plays a chord closer to D minor 9 or related variants depending on bell tuning specification, with notes around:
- D3 (~147 Hz) — fundamental on some K5 variants
- F3 (~175 Hz)
- A3 (~220 Hz)
- D4 (~294 Hz)
- E4 (~330 Hz)
The exact chord varies by manufacturing run and locomotive specification — the K5 was produced over decades with multiple tuning options. The K5LA standardized on the B major 6th (D♯/F♯/G♯/B/D♯) we describe in our K5LA sound page.
K5 vs. K5LA
- K5 (older): Multiple chord variants over its production run. Generally lower fundamental than the K5LA. Slightly more variability in voicing across units.
- K5LA (modern): Standardized B major 6th chord. Brighter, more uniform across the fleet. Adopted in the 1980s-90s and now the dominant model.
- Sound difference: The K5 sounds slightly deeper and "older"; the K5LA is brighter and more "modern train" voice.
- FRA compliance: Both meet 49 CFR § 222 96–110 dB at 100 ft when properly maintained.
Where to listen and download
- Train Horn Hub soundboard — synthesized chord (K5LA-tuned)
- YouTube — K5 recordings on legacy SD40-2 power
- Freesound.org — Nathan K5 samples (CC-licensed)
- /sounds/mp3-downloads/ — royalty-free samples (forthcoming)
What locomotives carry the K5?
The K5 was the standard 5-chime horn on North American freight from roughly the 1950s through the 1980s. Modern fleets have largely converted to the K5LA, but K5 installations persist on:
- Legacy EMD SD40-2 — many CSX, NS, and short-line units retain K5
- Older GE Dash 7 / Dash 8 power — held over from original delivery configuration
- Heritage fleets — railroad museum and excursion locomotives often keep period-correct K5
- Some short-line freight — small operators on rebuilt units
Why railfans prize the K5
Among rail enthusiasts, the K5 is often considered to have a "warmer" sound than the modern K5LA — partly nostalgia, partly the slightly lower fundamental, partly the variability across units. A K5-equipped SD40-2 horn on YouTube often gets more comments than a K5LA on a modern ES44.
For collectors and aftermarket buyers, recommissioned K5 units appear occasionally on railroad surplus markets. They command similar prices to recommissioned K5LAs — $400-$800.
Audio character details
- Output: ~149 dB at the source (same envelope as K5LA)
- FRA grade-crossing: Compliant with 96–110 dB at 100 ft
- Chord character: Lower fundamental, slightly minor / dissonant voicing on some variants
- Sustain: All 5 bells fire simultaneously and sustain