PSI to Loudness Calculator — Train Horn dB by Tank Pressure
A train horn doesn't have a single dB rating — it changes with tank pressure. See how SPL curves from 60 PSI up to 200 PSI across real-world models.
Horn model
Drops as the tank empties — use your real cut-in PSI for worst-case
Estimated horn output
148dB
Threshold of physical damage.
At rated pressure — full volume.
Pressure → loudness curve
The curve follows SPL ∝ 10·log₁₀(P/P_rated). Below 80 PSI the chord can't stabilize and output drops fast. Above 150 PSI you get diminishing returns — nozzles saturate and +50 PSI only adds ~1 dB.
Reference points for this horn
- 60 PSI
- 83.3 dB
- 80 PSI
- 145.3 dB
- 100 PSI
- 146.2 dB
- 120 PSI
- 147 dB
- 150 PSI
- 148 dB
- 180 PSI
- 148.8 dB
SPL is a logarithmic scale — 3 dB means double the sound intensity, 10 dB means roughly double perceived loudness. Dropping from 150 to 100 PSI costs about 1.8 dB, which you can hear but is small. Dropping below the chord threshold costs 10+ dB and the horn sounds completely different.
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The link preserves your horn pick and PSI slider.