19,261. Knee, A. W. March 7, [date upplied for under Patents Act, A.D. 1901]. Signalling and communicating between trains ; signals on engines and trains; indicating condition of bridges and tunnels ; indicators and repeaters, point, or switch; contacts, electric.-Relates to an automatic electric block signalling system for indicating to the driver of a train the approach or presence of another train on the same track, and applicable also for use at switches, tunnels, bridges, curves, &c., where extra precautions are required. Each locomotive or car is provided with two batteries &c. 1, 2, either of which can be connected by the switches B', h' to a normally-open circuit comprising a bell or alarm H and two contact-brushes &c. F, F', adapted to make contact with a conducting-rail arranged on the track. The switches B', h<1> are connected by an insulating-rod r, and are set by the driver. In the position shown, the battery 1 is connected up to the brushes through the contact e and the contacts a, a', d. By moving the switch B' on to the contacts b, b<1>, the switch h' moving simultaneously on to the contact e', the battery 1 is cut out, and the battery 2 is connected with reversed polarity to the brushes, this latter being the arrangement for trains travelling in the opposite direction to that of the train in which the battery 1 is in circuit. The contact d is connected to the contacts a', b<1>, and to a contact g' in permanent electrical connection with one of the axles &c. E of the vehicle. For working on the block system, the circuit is completed between the brushes F, F<1> by the conducting-rail A', which consists of insulated sections overlapping to the extent required for the block sections. When only one train is on the section, the bell H is rung, indicating that the line is clear, but if a second train approaches in the opposite direction and enters the section, the bells are short-circuited through the wheels and ordinary rails C, and are prevented or stopped from sounding, thus indicating Àdanger. When a train is stopped, the driver moves the switch B<1> on to the contacts d, d<1>, thus forming a short-circuit for an approaching train. Similarly, when starting, he can move the switch on to the contacts a, a<1>, or b, b<1>, to signal a train in the front or rear. At tunnels, bridges, curves, &c., the conducting-rail A<1> extends the entire length of the structure or section, and. a short conducting- rail D', Fig. 5, is arranged at each end to give a warning to the driver. At switches, the switch tongue is provided with a contact-plate, which, when the switch is open, connects the rail A<1> with the ordinary rail, to short-circuit the bell of an approaching train.