Blue flag

Requirements for using this cautionary sign in railway operations.


The blue flag is a cautionary sign that is constructed of a durable material with dimensions equal to or greater than 30 by 38 cm with the word "STOP" in white capital letters – 10 cm high.

It is printed on a blue background stated in Containers for Transport of Dangerous Good by Rail, a Transport Canada Standard, Section 10.6.2(d).

Using a blue flag

The blue flag is mandatory for both dangerous and non-dangerous goods transloading.

Blue flags are displayed to warn approaching railway vehicle operators when rail cars are being loaded and unloaded.

A blue flag is also used to indicate that workmen are in the vicinity of rail equipment.


Personnel must be trained to use a blue flag. Companies must develop and implement instructions on the use of a blue flag.


The blue flag is displayed on a section of track or on a railway vehicle to warn approaching railway equipment operators.

See Industrial Railway Regulation, Schedule 1, Section 8.1 "Blue Signal Protector".

Setting up a blue flag

Facility staff working on or around railway equipment are responsible for setting it up. The same work group who set it up must also remove it.

Rail service provider personnel do not remove the blue flag.

Contact your rail service provider or a rail maintenance contractor to obtain a blue flag.