wigwag

A wigwag is a mechanical grade crossing warning device consisting of a weighted wooden or metal arm that swings side to side across the roadway. When activated by an approaching train, the arm oscillates back and forth at roughly 45 to 50 cycles per minute, blocking the path and drawing the attention of road users to stop. The motion itself, not a light or bell alone, is the primary warning signal, which is why the device earned its onomatopoetic name.

Wigwags became common at railroad crossings in the early 20th century as a step above simple passive crossing signs. The arm typically measured around 6 to 8 feet in length and was counterbalanced to swing freely. Early models were actuated directly by crossing gates or train detection circuits; as electrical systems improved, pneumatic and electromechanical activation replaced purely mechanical linkages. The device was often paired with a bell or, later, electric lights to reinforce the warning.

The real advantage of a wigwag over static signage is the movement itself. A swinging arm catches the eye far better than a painted sign, especially to drowsy drivers or those distracted at night. The repetitive motion also persists as long as the train is in the crossing zone, giving multiple chances for a driver to notice and react. This made wigwags popular on rural and suburban roads where crossing gates might be deemed too costly or where traffic volumes did not yet warrant full gate installation.

Decline and variants

Today, wigwags have largely been superseded by flashing red lights and automatic crossing gates, which offer clearer legal liability protection and better nighttime visibility. However, some remain in service on lightly traveled branch lines and rural crossings, particularly where maintenance budgets are constrained or where federal funding for grade crossing upgrades has not yet been directed. A few railroads still maintain wigwag mechanisms as secondary indicators alongside modern equipment.

The mechanical simplicity of a wigwag is both its strength and weakness. It requires no electrical power to swing once activated, yet the moving parts, pivots, bearings, and the arm itself, wear and can stick or bind in winter weather or when debris accumulates. Counterweight corrosion and rust can throw the balance off, causing uneven or sluggish motion. When a wigwag fails to oscillate properly, it becomes ineffective precisely because users rely on the movement to perceive danger.

In trade parlance, wigwags are classified as passive warning devices, distinct from active crossing protection like gates. Railroad workers and crossing inspectors use the term to refer specifically to the swinging-arm type, not to light-only or audible-only warnings. On track diagrams and crossing inventory lists, you will see them marked as "WW" or listed by their manufacturer's model designation. Their presence at a crossing often signals historical installation or a low-priority crossing in the railroad's modernization schedule.