GB724645A - Train-counting railway signalling system - Google Patents

Abstract

724,645. Railway signalling systems. SOC. TECHNIQUE POUR L'INDUSTRIE NOUVELLE SOC. ANON. STIN. Nov. 29, 1950 [Dec. 9, 1949], No. 29277/50. Class 105. A railway signalling system whereby an entrance signal may be cleared so that succeeding following trains may pass into a section but in which a signal at the other end cannot be cleared for an opposite train until all the first trains have passed through has counting units operated by each operation to initiate the clearing of the signal and by each entry of a train, a comparison relay being energized only when these two counting units agree and only when this relay is energized can the signal be cleared for a following train, the actual clear. ance of the signal requiring that the operation to clear the signal shall have been counted and thus have caused the comparison relay to drop. To clear a signal to permit entry of a train the operator briefly depresses a push SH, Fig. 3, whereby a control relay STR is picked up over a front contact A<SP>1</SP> of a comparison relay A, Fig. 1, which is energized only when wiper contacts KBa and KBb are in the same position. The relay STR then sticks by its contact STR<SP>3</SP> while its contact STR<SP>2</SP>, Fig. 2, energizes the stepping magnet Wa for wiper KBa which by moving to its next position de-energizes the comparison relay A a back contact A<SP>2</SP> of which in conjunction with a front contact STR<SP>1</SP> of the control relay lights the clear signal lamp SL. When the train enters the section it depresses a slow-rise track contact to close a contact SKa, Fig. 2, whereby the stepping magnet Wb for wiper KBb is energized to move wiper KBb to its next position and so again energize the comparison relay A. The depressed track contact also opens a contact SKc, Fig. 3, to drop the control relay STR. The clear signal lamp SL is extinguished by the opening of the back contact A<SP>2</SP> and of the front contact STR<SP>1</SP>. The apparatus is now in its original state, except that wipers KBa, KBb have each advanced one step, and a signal can now be cleared for a following train.