Related Clues:

• Honk horn — in both directions
• Be a whistleblower
• Blow on a horn
• Blast back and forth
• Sound a car horn
• ''Beep!'' on the ocean
• Car horn sounds
• Choo-choo sound
• Noise from a toy train
• Sound from a train
• Railroad crossing sound
• Horn blasts
• Rush-hour cacophony
• Tug's signal
• Tugboat's horn sound