The black-and-white sign with dots tells the plow operator to raise flanges prior to crossings, switches, etc.
Greg McDonnell
Q What does a whiteboard sign with black circles mean? It’s near grade crossings and sometimes has one black circle, and sometimes two.
— Mike Cough, Kemptville, Ont., Canada
— Mike Cough, Kemptville, Ont., Canada
A That board (which can also be black with white dots) advises snowplow crews to raise flanger blades in advance of crossings, switches, and other between-the-rail obstructions. These signs are also often outfitted with angled fins to advise crews to retract plow wings in advance of clearance restrictions. They’re quite useful, especially when plowing at 45-50 mph in whiteout conditions.
— Greg McDonnell
