Abstract: A computer based railway interlocking control system, having triple parallel redundant control computers (FIG. 2) provides greater system reliability as compared to a single computer system. The railway traffic control devices, e.g. points and signals, are arranged to be controlled by signals in one of two possible steady states, the interlocking control means (30, 31, 32, FIG. 2) is arranged to produce control signals in the steady state for de-energized or "safe" device settings and in an alternating state for energized or potentially "unsafe" settings. The alternating control signals (33, 34, 35 or 38) must be converted to the corresponding steady state to operate the devices thus, the converting or restoring circuit discriminates against dormant wrong side failures, i.e. "unsafe" signals to increase the inherent safety of the system.

Abstract: An electronic or computer-based railway control system including further safety checks in addition to normal safety interlocking. The present system carries out checks to see that operations, such as print switching and signal setting, are carried out in the correct sequence for a given route having regard to the position and movement of a train as indicated by track circuits. In a computer-based system appropriate checking routines may be written into the computer soft-ware.

Abstract: The specification discloses an electronic or computer-based railway control signal interlocking system. Signals representing the settings or conditions of railway control elements e.g. track circuits, signals and points, and their control signals are checked as usual by the interlock equipment to establish route safety. However failures in the system may only be discovered when a change to a control element setting is attempted. Since long periods can elapse between changes a failure may lie dormant for some time. In order to reduce dormant wrong side failure periods to a minimum the signals supplied to the interlocking equipment are periodically switched to a predetermined state chosen to prove that when the interlocking equipment receives the switched signal that a wrong side failure mode does not exist in the switched signal path.

Abstract: The invention concerns an electrically assisted pneumatic train braking system. In a normal emergency/service pneumatic braking system a pneumatic pressure change must propagate along the train braking system from car to car. The present system includes two valves which are connected to each end of the brake pipe of each car, the first is responsive to a pressure change in the brake pipe to produce an electrical signal and the second being responsive to the electrical signal to produce a pressure change in the brake pipe. Thus, the propagation time for the whole braking system is reduced to little more than that for the total length of the couplings between cars.

Abstract: A slack adjuster for railway brakes has an input member to which a brake force is applied and an output member movable coaxially therewith, a coupling element via which a brake force is transmissible between the two members and which is positively engaged with one of the members via a cooperating helical engagement means and is engageable with the other member via clutching faces which are retained in force transmitting engagement by the reaction forces produced by the helical engagement means when a force is transmitted between the members for a brake application, the clutching faces being disengageable when such reaction forces are removed to permit relative rotation of the members and enable wear or slack in the brake rigging to be taken up.

Abstract: A railway switch machine including a first fluid operated actuator for switching the movable points of the rails between two extreme positions for establishing respective routes of travel for railway vehicles, valve device coupled to the first fluid operated actuator to selectively open or to close a passageway coupled to opposite sides of a pressure differential responsive movable member of the first fluid operated actuator whereby when the valve device closes passageways wherein a fluid pressure differential may be established across the movable member to operate said first fluid operated actuator to thereby switch the movable points of the rails and when the first valve device opens the passageway, fluid may be directly exchanged between either side of the movable member such as to permit the movable points of the rails to be moved from one extreme position to the other extreme position by the passage of a railway vehicle trailing the movable points of the rails, a locking device and a second fluid operate

Abstract: A continuous quick service valve arrangement for a direct release brake control system is provided with a sensing valve responsive to reductions of brake pipe pressure in relation to a reference pressure to apply fluid under pressure via a choke to a pulsating device which operates a quick service valve to drive pulses of air out of the brake pipe for as long as the brake pipe pressure continues to reduce for a brake application, the pulsating device is operated by a biassed member which when operated by being displaced in response to attainment of a certain pressure in a volume supplied by the sensing valve presents a greater area to the volume and opens a discharge path for the volume to permit the member to repetitively operate and reset.

Abstract: A piston-cylinder arrangement comprising a cylinder member and piston means mounted slideably therein, the piston means comprising a piston member and a packing member mounted on the piston member for movement therewith, wherein said packing member has first and second axially spaced radially outer surfaces dimensioned such that each contacts slidingly against said cylinder wall and wherein the piston means comprises a lubricant reservoir in communication with the space between said surfaces, which space is substantially closed by said cylinder wall.

Abstract: A quick service valve is proposed for providing continuous quick service in connection with the operation of a direct release triple valve preferably also provided with an emergency portion having a sensitivity valve for providing a bleed of fluid pressure from a quick action chamber to follow the pressure reductions in a brake pipe, the apparatus having a reference pressure input path connected to the quick service chamber, a brake pipe pressure signal input path, a pressure responsive member responsive to a predetermined difference between the brake pipe pressure and the reference pressure to operate a valve to initiate a restricted discharge from the brake pipe to cause a reduction of the reference pressure and consequent reclosure of the valve. The operation is repetitive during continuing reduction of brake pipe pressure at sufficient rate.

Abstract: Slack adjusting means comprises a linearly movable input member, a linearly movable output member, and an element for transmitting a brake force from the input member to the output member, characterized in that the input and output members are constrained against relative angular movement, and in that the element is engaged with one of said members via co-operating helical thread means provided therebetween and is engageable with the other of said members via co-operable clutch faces provided therebetween and arranged such that in use the clutch faces are retained in force-transmitting engagement by the reaction forces in the co-operating helical thread means and are disengageable when said reaction forces are removed or relieved thereby to permit relative rotation, and hence relative linear displacement corresponding to the slack to be taken up, between the element and said one member in engagement therewith via the co-operating helical thread means.

Abstract: A continuous quick service device is proposed for use in conjunction with a direct release brake controlling triple valve and which, while not interfering with the emergency valve operation, operates by employing quick action chamber air both as a reference against which brake pipe pressure reductions are detected and as a source of air to operate a pressure responsive device in a reciprocating manner to discharge pulses of air from a reducing brake pipe to afford quick service operation of the triple valve both for initial application from a brakes released condition and for subsequent brake pipe pressure reductions giving rise to increased brake applications.

Abstract: A vehicle door arrangement in which a lower edge part of the door is retractable upwards into the main part of the door prior to opening. This ensures that when the vehicle is standing alongside a platform, there is no risk of the bottom of the door fouling the platform. The arrangement is particularly suitable for slide and plug doors which move outwards and then alongside the vehicle when opening. Even if the bottom of the door is normally above the platform, the invention provides an essential safety feature to cope with situations where the vehicle is abnormally depressed, e.g. by excessive loading or suspension failure. Moreover, the invention enables the height of the interior floor of vehicle to be optimized with respect to platform level so as to enhance passenger safety and convenience, whereas with prior art rigid one-piece doors, clearance requirements dictated non-optimum floor heights.

Abstract: This disclosure relates to a directional sensing arrangement including a rotatable member having a plurality of permanent magnets which magnetically influence a first and second spaced stationary sensor. The rotation of the member causes the magnets to sequentially operate the first and second sensors so that neither, either or both are actuated. The first and second sensors are coupled to a logic network which deciphers the sequential actuations for determining the direction of rotation of the rotatable member.

Abstract: Continuity detector apparatus is coupled into duplicate conductors connected in parallel between each rail of a track section and an energy source or occupancy receiver of an associated track circuit to detect and register a fault in either parallel conductor and to indicate need for corrective action to restore the operational security provided by the duplicate circuit paths. In one form, each detector is a two-winding relay with one winding inserted in series in each of the duplicate circuit paths so poled that equal track current flows in opposite directions in the winding, when both conductors are unbroken to hold the relay released. Any interruption of either parallel conductor causes the relay to pick up to register the fault and transmit a corresponding indication. In a second form, a different transformer winding is connected with each conductor.

Abstract: A brake actuator comprising: a piston-cylinder arrangement having a piston member and a cylinder member arranged for sliding motion relative to one another by fluid pressure medium; an elongate plunger longitudinally movable by one said member and comprising two mutually screw-threaded parts arranged to vary the effective or overall length of the plunger upon relative rotation of said two parts; a resilient spring torque motor for effecting said relative rotation, the torque motor being coupled to one of the parts for driving that part relative to the other part; and rotation preventing means comprising friction clutch or brake members coupled to said one part and releasable when the stroke of the plunger exceeds a pre-set or predetermined amount to permit torque transmission from the torque motor to said one part in a direction tending to increase the effective or overall length of the plunger.

Abstract: A vehicle door arrangement in which a lower edge part of the door is retractable upwards into the main part of the door prior to opening. This ensures that when the vehicle is standing alongside a platform, there is no risk of the bottom of the door fouling the platform. The arrangement is particularly suitable for slide and plug doors which move outwards and then alongside the vehicle when opening. Even if the bottom of the door is normally above the platform, the invention provides an essential safety feature to cope with situations where the vehicle is abnormally depressed, e.g. by excessive loading or suspension failure. Moreover, the invention enables the height of the interior floor of vehicle to be optimised with respect to platform level so as to enhance passenger safety and convenience, whereas with prior art rigid one-piece doors, clearance requirements dictated non-optimum floor heights.

Abstract: A mounting device is provided for mounting a door to a door supporting mechanism, the device including a mounting member which is slideable in a slot and which projects to be rotatably engageable with an eccentric aperture in a further mounting member which when assembled is itself rotatably located in a further aperture, the arrangement affording easy levelling and positioning adjustment and locking means being provided for locking the members together after such adjustment.

Abstract: A continuous quick service device is proposed for use in conjunction with a direct release brake controlling triple valve and which, while not interfering with the emergency valve operation, operates by employing quick action chamber air both as a reference against which brake pipe pressure reductions are detected and as a source of air to operate a pressure responsive device in a reciprocating manner to discharge pulses of air from a reducing brake pipe to afford quick service operation of the triple valve both for initial application from a brakes released condition and for subsequent brake pipe pressure reductions giving rise to increased brake applications. A relay valve serves to operate the pressure responsive device to provide additional sensitivity.

Abstract: An accelerated release valve is proposed for brake control valves, especially direct release triple valves, the accelerated release being triggered by rapid collapse or discharge of quick service volume pressure at commencement of a brake releasing mode.

Abstract: A spring brake actuator is proposed which is provided with an arrangement accessible from the outside for manually releasing the brake in the absence of fluid pressure to release it, the releasing arrangement comprising a member which rotates a splined force applying member relative to a force transmitting member against the force of a return spring which holds abutting ends of the splines of the elements mutually aligned.