The train horn is operated by the Locomotive Engineer (also known as the Train Driver), who is responsible for the safe movement and control of the train. The engineer uses the horn primarily as a safety device to warn pedestrians and motorists of the train's approach at public grade crossings, or when workers are on or near the tracks. There is a standardized "language" for train whistles: the most common sequence is two longs, one short, and one long blast, which is required by law at every public crossing. In 2026, many modern trains feature a "sequencer" button that allows the engineer to trigger this pattern automatically, but they can still manually control the horn for emergency warnings. Beyond safety, the horn is sometimes used for traditional ceremonies; for instance, at midnight on January 1, 2026, engineers at major stations like Mumbai’s CSMT performed a synchronized "horn salute" to welcome the New Year. While the sound can be a nuisance to those living near tracks, the engineer’s use of the horn remains the most critical non-visual way to prevent accidents and save lives on the global rail network.