[[File:BS Diagram.jpg|300px|thumb|right|Signalling diagram inside Bewdley South signal box showing track circuit indicators]]
A Track circuits are a system of train detection that relies upon the two rails forming a pair of electrical conductors along a designated section of railway. A power source (often a battery) is provided at one end and an electrical detector (often a relay) is provided at the other end. When the section of track is unoccupied the detector is energised. When the section of track becomes occupied by a train the wheels and axles short circuit the power source hence de-energising the detector and thus aid safe , indicating the presence of a train. In order to increase safety, track circuits are often interlinked with the levers in a signal box, preventing a signalman from accidentally moving points underneath a train operation, or permitting two trains to be signalled towards each other. A useful adjuct feature of this system track circuits is it can detect certain that they will show "occupied" in case of a broken rail conditions thus further improving safety, any conductive obstruction that touches both rails, or a failure of the power supply to the track circuit. Track circuits are installed at a number of locations stations on the SVR including , specifically [[Bridgnorth]], [[Arley]], [[Bewdley]] , and [[Kidderminster]]. Additionally, there is continuous track circuiting between [[Bewdley South signal box]] and Kidderminster, allowing the section top be operated by [[Acceptance Lever]].
