...Members would board the tailboard and when ready would push the button twice. The button was connected to the electric truck horn and would blow twice. If the engine had the radio keyed up back then....you could hear the Q kicking on and the horn beeping twice....

There was also 2 lights on the back of Engine 1....1 on the left and one on the right. The cab would activate the light(s) when they got to the scene indicating a lay out of 1 or 2 supply lines (Dual 3" or 2.5" lays early on).