Great Western Coffee Shop

Idle curiosity, but does anyone know why there are a number of whistle boards along the Golden Valley line where there are two whistle signs on the same post.  An instruction to sound the whistle/horn twice?

Something to do with when they used to bank freights up the incline from Brimscombe. Maybe they still do on odd occasions?

I couldn't give two hoots.

It's a warning to the drivers to keep an eye out for migratory frogs and toads. Poop poop!

To ensure visibility from different driving positions???

Is it something to do with the high number of footpath crossings and curves reduce visability. The trains do seem to run slowly along that valley

two foot-crossings = two whistle boards but sighting considerations mean that the boards should both be in approximately the same place, so someone decided they could share the same pole?   

There is nothing in Group Standards that I can see but GI//RT7033 (http://www.rssb.co.uk/rgs/standards/girt7033%20iss%202.pdf) on page 119 states that the sign should be at driver's eye level.  I wonder if a new eyesight level has been assessed (or just a scheduled renewal) and new signage has been added before the old signage is removed so that there can never be a gap in cover. One wouldn't want to be responsible for the lack of a warning at a crossing. Just a thought ...