Cooool pics!

So the tell-tales rang out when the train was taller than the tunnels/bridges it was going to go through/under?

Mako

PS: Howdy to K. for me too please :)

It was actually entirely there to brush against you if you were on top of a car mainly as a brakeman. Which hopefully you had enough time and coordination to climb down one of the car ladders.

In 1926, when the standard received it's last update, standards called for tell-tales to be placed 100 to 300 feet away from structures with a clearance of 21 feet or less above main lines or sidings.

It's a call back to the era before automatic air brake systems. It's also rather astounding that it not only remained on the SP long after that era ended, but also that it still remains today!