How loud is a train horn?
In the United States a locomotive horn must produce between 96 and 110 dB(A) measured 100 feet (about 30 m) in front of the train. That window is set in federal regulations, so every lead locomotive's horn sits somewhere in that band at that distance.
- Level
- 96–110 dBAA-weighted sound level
- Distance
- 30.5 m100 ft (30 m) in front of the locomotive
- Daily limit
- 1 min 29 s a dayNIOSH, at the loud end
- Versus conversation
- 11,220× energyabout 16.6× as loud
What the numbers mean
How it was measured. US federal requirement for the horn on the lead locomotive, measured 100 ft forward of the locomotive in its direction of travel.
The figure comes from 49 CFR 229.129, which requires each lead locomotive to carry a horn that produces a minimum sound level of 96 dB(A) and a maximum of 110 dB(A) at 100 feet forward of the locomotive in its direction of travel. The lower limit exists so that drivers and pedestrians at crossings hear the train coming; the upper limit caps the nuisance for people living near the line.
Because the rule is written for a point 100 feet ahead, someone standing beside the track as the locomotive passes is closer to the horn and will hear more than this, while a house a few streets away will hear much less. The rule also requires that the horn can be worked conveniently from the engineer's usual position.
How long is safe?
NIOSH recommends no more than 1 min 29 s a day at 110 dBA (38 min at 96). OSHA's legal limit is 30 min.
| Level | NIOSH limit (85 dBA, 3 dB rule) | OSHA limit (90 dBA, 5 dB rule) | UK/EU 80 dB(A) action value reached after | UK/EU 85 dB(A) action value reached after |
|---|---|---|---|---|
| 96 dBA | 38 min | 3 h 29 min | 12 min | 38 min |
| 110 dBA | 1 min 29 s | 30 min | 29 s | 1 min 31 s |
Times are for a whole day’s exposure, with the rest of the day quiet. The workplace limits were written for adults at work, not for children. Work out a mixed day with the noise dose calculator.
Protecting your hearing
Do not linger on platforms or crossings beside the track when trains are approaching. If you live near a crossing, closed windows and distance do more than anything else; if you work trackside, wear earplugs or earmuffs.
Earplug and earmuff ratings (NRR in the US, SNR in the UK and EU) are lab figures; real-world protection is usually lower. How to read the ratings.
Compared with sounds nearby
Using midpoints of each range. Energy multiplies by 10 every 10 dB; perceived loudness roughly doubles (why).
- Circular saw (89–110.4 dBA): this has about 2.1× its sound energy and sounds about 1.3× as loud.
- Hand dryer (80–121 dBA max): this has about 1.8× its sound energy and sounds about 1.2× as loud.
- Chainsaw (98.5–112 dBA): it has about 1.7× the sound energy of this and sounds about 1.2× as loud.
- Car horn (93–118 dBA max): it has about 1.8× the sound energy of this and sounds about 1.2× as loud.
- Normal conversation (55–70 dBA): this has about 11,220× its energy and sounds about 16.6× as loud.
Questions
Is there a legal limit on how loud a train horn can be?
Yes. In the US a lead locomotive's horn must produce no more than 110 dB(A), and no less than 96 dB(A), measured 100 feet in front of the locomotive.
Why are train horns so loud?
They have to be heard by drivers and pedestrians at crossings over engine and traffic noise, so US rules set a minimum of 96 dB(A) at 100 feet.
Sources
- 49 CFR § 229.129 - Locomotive horn., US Code of Federal Regulations (Legal Information Institute, Cornell). Supports: dB_low 96 and dB_high 110 dB(A) at 100 ft.
produces a minimum sound level of 96 dB(A) and a maximum sound level of 110 dB(A) at 100 feet forward of the locomotive in its direction of travel
Checked 2026-11-03.
This page is general information, not medical advice. If you have ringing in your ears, muffled hearing or any change in your hearing, see an audiologist or your doctor.