Abstract: A method is disclosed of detecting a railway vehicle, comprising using the time difference between receiving at first and second points a signal sent from the vehicle at a given time to produce an indication of the location of the vehicle.

Abstract: A train detection mechanism for detecting the presence of a train on a section of track, the track section including first and second rails 1, 2 and delimited by first and second ends thereof, includes current injector for injecting current into the first rail at the first end of the section and current receiver for receiving current from the second rail at the first end of the section, and a shunt 3 connected between the first and second rails at the second end of the section, characterized in that the shunt includes a switch 4 for controlling current flow through the shunt, the switch being operable by the passage of a train.

Abstract: A system is disclosed for monitoring condition of a railways installation such as a points machine. The system includes a plurality of sensors (S1, S2, S3-SN) associated with elements of the installation for monitoring parameters indicative of operating capability of the installation. The system includes means (12, 23) for processing the monitored parameters to determine whether the parameters are changing relative to reference values and to determine whether the changes are indicative of an increased risk of malfunction in the installation. The processing means may include a digital computer programmed with condition monitoring and fault detection software. A method of monitoring condition of a railways installation is also disclosed.

Abstract: Railway track circuit apparatus for train detection comprises a track circuit transmitter and a receiver, wherein the transmitter generates a QPSK modulated signal that is transmitted into a track circuit and which is detected by the receiver.

Abstract: An LED signal lamp comprises at least two separate LED arrays which have separate power feeds and wherein the LEDs of the arrays are positioned with respect to each other such that when lit they provide a composite light signal output and such that when the LEDs of only one of the two arrays are lit they provide a light signal with a visible distinctive pattern. A distinctive pattern is revealed, either lit or dark. Typically this pattern may be formed as a letter such as “X” or “F” or may be formed as a striped effect, for example.

Abstract: A train location arrangement interleaves a plurality of detection systems to provide, in combination, a higher resolution of train detection than would be provided by one of the systems on its own.

Abstract: A train location arrangement is disclosed that interleaves a plurality of detection systems to provide, in combination, a higher resolution of train detection than would be provided by one of the systems on its own.

Abstract: Apparatus for controlling a brake system operable using an air supply, includes an electronic control (8) for controlling air distribution and air to an air to electrical converter (12) for generating an electrical supply for energising the electronic control using air under pressure from the air supply (1). Air distribution is controlled either as a result of sensed pressure in a brake control pressure pipe (6) or as a result of an electronic brake control signal.

Abstract: A point drive unit (10) is disclosed for driving railway points to move via a connecting means of the points located generally centrally between two of the rails (3) of the railway track. The unit comprises a housing (11, 12) adapted to be installed between the two of the rails; a cylinder (18) enclosing a piston (19) which is moveable for driving the points, the cylinder being mounted within the housing at a location laterally offset to one side of the housing; control means mounted within the housing at a location laterally adjacent the cylinder for controlling the supply of fluid to the cylinder to control the movement of the piston; and an offset coupling (20) for coupling the piston to the connecting means so that the piston is laterally offset from the connecting means.

Abstract: A vehicle control system issues control signals to vehicles to control their movements along a route between a first location and a second location, the vehicles comprising a set of vehicles of a first type, to which the system can issue control signals at more than one location within the route, and a set of vehicles of a second type to which the system cannot issue control signals at more than one location within the route. Sending devices sense vehicles entering and leaving the route and the type of these vehicles, storage devices stores a record of the number of vehicles within the route and a record of the type of vehicle that most recently entered the route, signalling devices signal to vehicles whether they may enter the route by moving beyond the first location and control devices receives information from the storage devices and transmits signals to the signalling devices.

Abstract: Thresholds for bridging the gap between a platform and doorways of vehicles stopped at the platform. The thresholds are adapted to move from a retracted position to an extended position in response to the opening of barrier doors mounted alongside the platform.

Abstract: A semiconductor device comprises a plurality of IGBT-like cells arranged in groups on a single wafer of silicon. Each group of cells has a unified gate structure and a unified source structure electrically insulated therefrom but physically overlying it. The gate structure of each group of cells is brought via a removable link to a single gate electrode for the whole device, so that the gate connection to any group of cells may be broken by removing the link, thus disabling the corresponding group of cells. Also, each group of cells is provided separately with a built-in controlled shunt conductance between its source structure and its gate structure.

Abstract: A system is disclosed for testing a plurality of items of test data, the system comprising memory means for storing a plurality of items of stored data and, in response to an input signal identifying one of the items of stored data, producing an output signal dependent on that item of stored data. The input signal is dependent on one of the items of test data and on a feedback signal comprising at least part of the output signal produced on testing a previous item of test data, at least part of the output signal providing an indication of the result of the testing.

Abstract: A process for manufacturing a semiconductor switching device (such as a thyristor device) comprises: etching a face of a semiconductor body to provide islands and channels which define a mesa-contoured surface; diffusing dopant of a first conductivity type through said surface so that the lines of equal concentration of the dopant in said body follow substantially the mesa-contoured surface; and diffusing dopant of a second conductivity type into said islands to form p-n junctions with said dopant of a first conductivity type. The diffusion of said dopant of a first conductivity type is followed by an out-diffusion step so that the dopant concentration of said dopant of a first conductivity type is at a maximum at a depth below said surface.

Abstract: An interlocking system for a railway comprises a plurality of processors (A, B and C), the system having an input (1) for receiving input information and an output (2) for providing control information. Each of the processors is adapted to test itself to check that it is operating correctly and each of the processors is also adapted to test another of the processors to check that the other processor is operating correctly, each of the processors also being so tested by another of the processors. The system is shut down or put into a more restricted mode of operation if a fault in its operation is detected, either as a result of a processor's self-testing routine or as a result of one of the processors detecting that another processor is not operating correctly. This achieves the integrity of a "dual-channel" system with only a single "channel" of hardware.

Abstract: A railway signalling system comprising a control device for controlling the movements of railway vehicles on a railway track.

Abstract: In a railway signalling system, to achieve inter-vehicle headway spacing for railway vehicles (1) travelling on a track (T), there are a) control of vehicles by fixed block signalling and b) control of vehicles by moving block signalling via communication between vehicles. The moving block signalling occurs within a moving block control zone of the track and the fixed block signalling occurs outside that zone, there being the facility of two-way data transmission between vehicles throughout the moving block control zone and the fixed block signalling system not preventing a further vehicle from entering the mowing block control zone when another vehicle is already in that zone and receiving a transmission via the moving block signalling system.

Abstract: In a railway signalling system, the length of a vehicle or train is computed by on board measurement of the distance travelled between detecting the passage of the front of the vehicle or train past a fixed point and detecting the passage of the rear of the vehicle or train past the same fixed point or a fixed point a known distance from the first.

Abstract: A circuit arrangement for detecting an input voltage comprises an oscillator responsive to the voltage, the oscillator including a pair of transistors (8, 9) connected as an astable multivibrator, each of the transistors having a load which comprises a primary winding (16 or 17) of a current transformer (T) and a low resistance proof resistor (12 or 13). A current flows through a secondary winding (18) of the transformer the amplitude of which current is proportional to the input voltage.

Abstract: A circuit arrangement includes a lamp filament (1) as a load and a resistor (2) in series with the filament. For detecting the current through the load, the source of a MOSFET (6) is connected with the end of the resistor remote from the filament, the drain of the MOSFET being connected with the other end of the resistor via the primary winding of a step-up transformer (7) and a further resistor (8), a diode (9) being connected between the source and the drain of the MOSFET. If the MOSFET is turned on by an appropriate voltage at an input (11) connected to its gate, the voltage across the secondary winding of the transformer is substantially proportional to the value of the current through the filament.