Abstract: The apparatus of this invention is a broken rail detection system that detects rail and/or rail breaks in dark territory track sections, i.e. track sections that do not have signalling systems. In one embodiment of this invention a system is disclosed in which a communications link exists between the ends of the track sections and in another embodiment of this invention no communications link exists between the ends of the track sections.

Abstract: A transformer includes first and second coils which are generally cylindrical and having an outer circumferential surface, an inner diametral surface and first and second axial extremities. Shielding is disposed around the coils comprising a web shaped metallic, non-magnetic, electrically conductive generally rectangular first member. The first member has a first portion extending about substantially the entire inner diametral surface of the coils and has a plurality of tab shaped portions extending respectively about a substantial portion of each of said first and second axial extremities. A second non-magnetic, electrically conductive metallic member extending over substantially the entire circumferential extent of each coil.

Abstract: A transformer apparatus which includes a core and first and second coils which are each magnetically coupled to the core. Each coil is generally cylindrical and have a circumferential surface and first and second axial extremities. Shielding is disposed around at least the first coil comprising a web shaped metallic, non-magnetic, electrically conductive generally rectangular member. The member has a first portion extending around substantially the entire circumferential extent of at least one coil and the member further includes second and third portions extending respectively about a substantial portion of each of the first and second axial extremities.

Abstract: Broken rail detection in a block of track without the need or expense of conventional signalling uses a chain of transmitters and receivers connected to the rails and defining sections of the block between the ends of the block. Either cyclically at a predetermined code rate or upon command of an external unit; an alternating current (AC) signal is launched from one end of the block and is repeated at different frequencies in each of the sections. When received at the end of the block, an indication of the absence of a broken rail condition is given either (a) by way of pole line or radio communication to a central control or dispatcher point and thence back to the trains, or (b) signals at the ends of the block are flashed at the code rate. The detected signal at the code rate may be used to modulate a direct current which is transmitted along the rails in the block to a signal at the opposite end of the block which also flashes at the code rate to indicate a safe condition.