Nathan K3LA Train Horn Sound
The 3-chime cousin of the K5LA. Smaller, lighter, used on switchers, short-line freight, and lighter passenger units. Same chord voice, fewer notes.
Nathan K3LA train horn — royalty-free CC0 sample (BigSoundBank)
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What it sounds like
The K3LA plays a 3-chime subset of the K5LA's B major 6th chord. Most common configuration:
- D♯3 (~311 Hz) — fundamental
- F♯3 (~370 Hz) — minor third
- D♯4 (~622 Hz) — octave
The chord is sparser than the K5LA — less "thick" but still recognizable as a Nathan AirChime voice. Some K3LA installations use alternate note voicings (D♯/G♯/D♯ or F♯/B/D♯) depending on locomotive specification.
Where to listen and download
What locomotives carry the K3LA?
The K3LA is installed where weight, packaging, or specification calls for fewer chimes than the K5LA:
- Yard switchers — EMD MP15, GP9R rebuilds, GE B23-7 (smaller air supply favors fewer chimes)
- Short-line and regional railroads — older units rebuilt without full K5LA installation
- Light passenger / commuter rail — some older Metra and SEPTA equipment
- Maintenance-of-way — work trains and track inspection units
- Class III freight — small operators on legacy power
Modern Class I freight and modern passenger fleets standardize on the full K5LA. The K3LA appears mostly on older or specialty equipment.
K3LA vs. K5LA — when each is used
- K5LA (5 chimes): Modern Class I freight, mainline passenger, anywhere weight isn't a constraint. The standard.
- K3LA (3 chimes): Switchers, light power, older rebuilds. Same chord voice but sparser and slightly less dB at peak.
- Sound difference: The K5LA's fifth and sixth notes (G♯ and B) "fill" the chord. Without them, the K3LA sounds more open and slightly thinner.
- FRA compliance: Both meet 49 CFR § 222 96–110 dB at 100 ft when properly maintained.
Audio character details
- Output: ~146–148 dB at the source (slightly less than K5LA's 149 dB peak, due to fewer chimes contributing)
- FRA grade-crossing: Compliant when measured at 100 ft
- Chord character: Brighter than the K5LA — fewer notes mean less harmonic density
- Sustain: All 3 bells fire simultaneously and sustain
Aftermarket K3LA replicas
The K3LA is less common than the K5LA in the aftermarket — most consumer kits target the louder K5LA chord. For 3-chime kits see: