mechanical interlocking

There was a recent modeling article about interlocking rods and links. Just how far could the links and rods be used from a towerand was there a distance limitation depending on how many turns the rods took? I'm sure this had to be a maintenance nightmare for the railroads.

I wish somebody would answer this -- I've often wondered about it myself. What was the practical distance from the tower for an armstrong switch?

Mechanical interlocking had runs of up to 3/8 of a mile or almost 2000 feet. If that pipeline run controlled a crossover switch, it's maintenance had to be exemplary and the leverman really had to engage his 'ass' to operate it.