US PATENT SUBCLASS 246 / 41
.~.~.~ Direct current, normally closed, track circuit

Current as of: June, 1999
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246 /   HD   RAILWAY SWITCHES AND SIGNALS

20  DF  BLOCK-SIGNAL SYSTEMS {4}
27  DF  .~ Automatic {5}
28 R  DF  .~.~ Electric {18}
41.~.~.~ Direct current, normally closed, track circuit {4}
42  DF  .~.~.~.~> Propulsion-current return {1}
44  DF  .~.~.~.~> Wireless distant control {1}
46  DF  .~.~.~.~> Line-wire distant control {5}
54  DF  .~.~.~.~> Single block {1}

DEFINITION

Classification: 246/41

(under subclass 28) Systems in which a direct, normally closed, continuous current, either actuating or controlling traffic-controlling devices and derived from a source not on the train, uses both traction-rails in series as conductors for the major portion of the block.

(1) Note. This type is known to the Railway Signal Association by the title "D.C. automatic block".

SEE OR SEARCH THIS CLASS, SUBCLASS:

26, 34+, 58+, 95, 98, 128+, and 130, for track-circuit systems.

70, for cab signal or train-control systems similar to that in this subclass.

130, for highway signals, gates, and doors actuated or controlled through closed track-circuits.

160, for switch-locks controlled by electric track-circuits. 253, for devices for breaking the continuity of the circuit when a switch is misplaced or a signal goes to danger.

449, 450 and 451, for tie-bars with insulated joints.

SEE OR SEARCH CLASS

238, Railways: Surface Track,

164, for the structure of rail-bonds and subclass 152 for insulated rail-joints.