US PATENT SUBCLASS 246 / 34 R
.~.~.~ Varying-current 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}
34 R.~.~.~ Varying-current track circuit {9}
35  DF  .~.~.~.~> Propulsion-current return {1}
38  DF  .~.~.~.~> Wireless distant control
39  DF  .~.~.~.~> Line-wire distant control
40  DF  .~.~.~.~> Single block
34 A  DF  .~.~.~.~> Approach control
34 B  DF  .~.~.~.~> Coded circuits
34 C  DF  .~.~.~.~> Insulation breakdown
34 D  DF  .~.~.~.~> Saturable reactors
34 CT  DF  .~.~.~.~> Continuous track

Unofficial Alpha Subclasses: R A B C D CT

DEFINITION

Classification: 246/34

(under subclass 28) Systems in which an alternating or pulsating current used for actuating or controlling the traffic controlling devices and derived from a source not on the train uses both traction rails as conductors in series for the major portion of the block.

SEE OR SEARCH THIS CLASS, SUBCLASS:

26, 41+, 58+, 95, 98, 128+, and 130, for track-circuit systems.

176, and 253, for switch or signal actuated circuit-breakers in track-circuits.

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.