Whistle post

In Australia, whistle posts consist of a pole or upright flat-bottom rail with a white or reflective yellow X.

Estonian whistle posts are inverted pear-shaped white plates, the lower third of which is green.

An additional white board with a black 'J' for "jour" ('day') indicates that the sign does not apply at night time.

[1][2] Whistle posts in the United States and Canada are traditionally placed 1⁄4 mile (400 m) in advance of a road crossing.

[3] A yellow diamond with black edges, Signal 67,[5] or one of its varieties, is placed 250–500 metres before halts and level crossings, where the public is not otherwise warned about approaching trains.

[6] In the People's Republic of China, a whistle board is a white diamond with a black border with the character míng 鸣 ('whistle') on it.

One modern variation found in Scotland is the 'continuous' whistle board, comprising a white rectangle with the W below a diagonal cross.

Whistle post on the North Shore Scenic Railroad in Minnesota
The sign on a Queensland whistle post on the old Gibson Island line
Estonian whistle post at Raasiku station
German double whistle post under a speed sign
An old whistle post in the United States
Whistle post with multiple crossings in Valdosta, Georgia
PKP W6b whistle board for road level crossings not secured or not included in station or line interlocking devices
British Rail modern whistle board at Castlerock