246 / | HD | RAILWAY SWITCHES AND SIGNALS |
20 | DF | BLOCK-SIGNAL SYSTEMS {4} |
27 | DF | .~ Automatic {5} |
28 R | DF | .~.~ Electric {18} |
77 | DF | .~.~.~ Counting in and out {1} |
78 | DF | .~.~.~.~ Ratchet wheel {1} |
79 | DF | .~.~.~.~.~ Double opposed pawls {1} |
80 | .~.~.~.~.~.~ Parallel teeth |