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 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: 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 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.

Abstract: A valve arrangement is provided for giving a continuous quick service facility in a triple valve controlling rail vehicle brakes in response to brake pipe pressure reductions. The arrangement comprises a pressure responsive member which responds to more than a predetermined brake pipe pressure reduction in relation to a reference pressure to operate a pulsator which discharges repetitive pulses of air from the brake pipe for as long as the pressure reduction persists.

Abstract: A transistor drive circuit arrangement in which the collector current of a transistor is passed through the primary or control windings of a direct current current-transformer or transductor and the secondary or output windings of the current-transformer or transductor control the passage of alternating current via rectifying means which provides base current drive for the transistor. Thereby the base current is directly related to instantaneous collector current which results in significant power economies relative to prior art arrangements in which the base is continuously over-driven to ensure permanent base-emitter saturation.

Abstract: An air operated brake actuator has an air pressure operated brake force applying member, the application to and removal of pressure from which member determines the brake force, another such member which must be separately pressurised to follow the first member to lock in a brake force, and yet another member which requires to be additionally pressurized to effect unlocking of the brake force.

Abstract: A railway air brake pipe pressure gradient reduction arrangement, wherein pressure gradients along the pipe indicative of a brake pipe pressure fall activate a valve arrangement to temporarily vent the pipe and so speed the brake applying pressure reduction. A further valve arrangement is included for inhibiting venting when a pressure gradient is present due to a pressure rise.

Abstract: A driving and locking mechanism which employs pivoted links for coupling and transmitting motion between driving and driven members. During motion, the links are constrained to a particular mutual position for transmission of driving forces, but at one end of the range of movement, the constraint is removed and the links pivot so that one link comes into normal or over-normal contact with an abutment and so locks the driven member in position. Forces on the driven member will not move it (except in the case where the abutment is resilient to allow limited movement of the driven member in the "locked" position) and movement of the driven member can only be accomplished by movement of the driving member. Thus a separate locking or latching mechanism is not required. The mechanism is particularly applicable to sliding doors, such as those of railway vehicles, where the door needs to be locked or latched in the closed position against forces applied to the door to tend to open it.

Abstract: A magnetic amplifier is disclosed which has improved fail-safe characteristics, the amplifier has a pair of saturable magnetizable cores with d.c. control winding turns on each which are mutually decoupled in known manner with regard to input a.c. windings and the a.c. windings also have linked with them a further magnetizable core, the output from the transductor being derived from a secondary winding on the further cores. The arrangement enables various applications of a magnetic amplifier to be made which might otherwise be objectionable by reason of the reduced operational failure-to-safety characteristics. These applications include use in a brake control circuit.

Abstract: A brake control valve apparatus is proposed for the respective cars of a train controlled from one end or the other to be braked by an analogue signal of variable mark-to-space form which operates on each car to gate bursts of train-wire carried a.c. supply which after rectification are used to regulate the brake pressure via an E.P. converter. Additionally in order to enable release of a braked car which fails to release its brake in a tunnel, a train brake release wire is provided which in one example operates in an energized-to-release mode to release a single failed brake or in another example operates in a de-energized to release mode to connect local supplies to operate dump valves on all the brake actuators of the train so providing total release in addition to the normal release by the control valve.

Abstract: This disclosure relates to a vehicle speed signal pulse generator employing a multi-limbed magnetic stator structure and a rotatable magnetic rotor. The multi-limbed magnetic structure includes a pair of magnetic core members about which are wound a primary and secondary winding. A permanent magnet is located in the multi-limbed magnetic structure to cause polarized magnetic flux to flow through each of the magnetic core members. A source of oscillating signals is connected to the input terminals of the primary winding to produce a.c. oscillations in the secondary winding when the vehicle is at rest. The magnetizable rotor includes a plurality of circumferential teeth disposed adjacent the magnetic stator structure to modulate the a.c. oscillations so that the modulated signals developed on the output terminals of the secondary winding will be indicative of the speed of the moving vehicle.