Why Do Trains Blow Their Horns?

When a train rolls through a grade crossing, you may recognize the various horn blasts as it makes its presence known. Many may wonder why trains blow their horn in the same sequence when they are approaching a grade crossing.

So, why do trains blow their horn? Trains are mandated by the Federal Railroad Administration (FRA), to sound the horn in a long, long, short, long sequence in order to alert motorists at grade crossings. 

There are various horn sequences that are utilized for other railroad operations as well, such as in rail yards. Furthermore, there are a plethora of reasons that trains sound their horn, much to the chagrin of the surrounding communities.


Since the genesis of the railroad in the 19th century, train whistles have blown throughout the busiest cities and the most rural countrysides. There are a number of reasons a train blows its horn, and a variety of regulations concerning when and for how long a horn must sound.

Trains in the United States blow their horns at grade crossings in the United States due to laws put forth by the Federal Railroad Administration (FRA). FRA rules state that whenever a train passes a “W” or “W/MX” sign indicating whistle, the train must blow their horn for a grade crossing, bridge, or yard ahead. According to the Northeast Operating Rules Advisory Committee (NORAC), the following is stated about horn usage:


(a) — Crew members apply brakes.

(b)— — o — 1. Approaching public crossing at grade and at a whistle post indicating “W” or “W/MX.” This signal is to be prolonged or repeated until engine or train is on the crossing, or, where multiple crossings are involved, until the last crossing is occupied. The whistle or horn must not be sounded at a whistle post indicating “W/R,” except in case of emergency.

2. Approaching locations where Roadway Workers may be at work on tracks, bridges and other points.

3. Approaching and passing standing trains.

(c) Succession of Alarm for person or animal on or about the track.

short sounds

(d) — o When running against the current of traffic:

1. Approaching stations, curves, or other points where view may be obscured.

2. Approaching passenger or freight trains; when passing freight trains.

3. Preceding 19(b), (1) and (2).

(e) o o o 1. When standing: warning or acknowledgment that the train is to back up.

2. When running: acknowledgement that the train is to stop at next passenger station.

(f) o o 1. Acknowledgment of a Stop Signal other than a fixed signal.

2. Acknowledgment of any other signal not otherwise provided for.

(g) o o o o Call for signals.

(h) — — — — Member of crew providing protection may return.

If all engine whistles or horns fail en route, the Engineer must take the following actions:

  1. 1. Notify the Dispatcher as soon as practical.
  2. 2. Ring the bell continuously, if equipped.
  3. 3. Approach all public crossings at grade prepared to stop.
  4. 4. Reduce speed to not exceeding 30 MPH while approaching locations where employees are known to be working.
  5. 5. Reduce speed at other locations where warranted by the prevailing conditions.
Jeff Hampton

Grade Crossings

Grade crossings are located where a road crosses railroad tracks, usually protected by either flashing lights and a gate, just flashing lights, or at a minimum, crossbucks. However, these warning signs are not enough for many drivers, as train crews constantly find themselves dealing with vehicles attempting to beat the train to the crossing, which many times, result in a tragic accident. Prior to occupying a grade crossing, the engineer is to sound the horn at least 15-20 seconds prior to reaching the crossing.

The common protocol is to sound the horn in long, long, short, long blasts until the locomotive or lead car is occupying the crossing. Oftentimes, there are signs prior to the crossings known as “whistleposts”, which either depict “W”, meaning whistle or horn, or “W/MX”, meaning “whistle multiple crossings.” Additionally, if a train is approaching a station at track speed, they are required to sound the horn to alert the individuals on the platform.


Although many enjoy hearing the horn in the distance late at night, others find the horn blasts to be a nuisance, and disturbing the peace. In recent years, communities have rallied against the use of train horns, especially in densely populated areas, or within small towns. Many railroads did not want to compromise the safety of the communities trackside, thus, another option was implemented to appease the opposition.

In areas where opposition to the usage of train horns was most prominent, wayside horns were implemented. When a train approaches a crossing equipped with a wayside horn, the wayside horn sounds in lieu of the engineer sounding the locomotive air horn. This reduces the ambient noise of the train horn, as the wayside horn is much quieter, and only those in the vicinity of the crossing hear it.

Although wayside horns have proved effective, some railroad crossings are designated as “quiet zones”. Quiet zones require the engineer to ring the bell while passing through the crossing but not sound the horn. Although quiet zones are popular with local communities, accident rates between cars and trains are considerably higher.

Jeff Hampton

Operational Implications

The locomotive horn is utilized much more than just at grade crossings and stations. Although, since the 1960s, radios have become the standard mode of communication on the railroad, whistle and horn signal were commonplace until the mid- 20th century. While completing various yard duties, the locomotive horn is sounded twice prior to moving forward, and three times prior to reverse operations. This effectively warns any personnel near the tracks that a train is setting into motion. In addition, when passenger trains leave a station, they may occasionally sounds the horn.

According to Trains Magazine, and The General Code of Operating Rules, the following denotes the whistle and horn signals utilized before the days of the radio:

Note: “o” denotes a short sound; while a “-” is for a longer sound.

– When stopped, air brakes applied, pressure equalized.

– – Release brakes, proceed.

0 0 Acknowledgement of any signal not otherwise provided for.

0 0 0 When stopped, back up; acknowledgement of hand signal to back up.

0 0 0 0 Request for signal to be given or repeated if not understood.

– 0 0 0 Flagman protect rear of train.

0 0 0 – Flagman protect front of train.

– – – – Flagman may return from west or south.

– – – – – Flagman may return from east or north.

– – 0 – Approaching public grade crossing.

0 – Inspect brake system for leaks or sticking brakes.

A series of short blasts is sounded in an emergency.


Lifelong Rail Enthusiast and Owner of Worldwide Rails

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