Abstract: A manufacturing method of a railway braking device is described comprising a main body arranged to receive at least partially: at least two different pneumatic or electro-pneumatic elements; and channels connecting the at least two pneumatic or electro-pneumatic elements; the manufacturing method comprising the step of: constructing said main body of the railway braking device through additive manufacturing of a monolithic block provided with at least two seats for said at least two pneumatic or electro-pneumatic elements and said channels; a railway braking device is further described constructed by means of a manufacturing method of a railway braking device.

Abstract: In addition to liquid in a thermal volume-neutral stroke transmitter, first and/or second displacement body(ies) is/are positioned in the stroke transmitter, for displacing the liquid. These three materials in the closed system are designed so that the stroke transmitter remains pressure-free during temperature changes.

Abstract: The dual vent valve includes a housing having brake pipe, emergency input and exhaust ports, and first and second valves. The emergency output port is fluidly connected to the emergency input port. The first valve selectively connects the brake pipe port to the exhaust port by opening the first valve in response to an emergency signal on the brake pipe port. The second valve selectively connects the brake pipe port to the exhaust port by opening the second valve in response to an emergency signal on the emergency input port.

Abstract: A multi-circuit protection valve is provided for a vehicle compressed-air supply device. A first port for a service brake includes two mutually separate service brake circuit ports for a first service brake circuit and a second service brake circuit. The two service brake circuit ports are protected by first and second service brake circuit overflow valves, respectively. A second port for a parking brake, is protected by an overflow valve, wherein one of the two service brake circuits can be filled preferentially. The overflow valve has two active surfaces which can be acted on with a valve inlet pressure and a valve outlet pressure, respectively. The overflow valve has a third active surface, which is acted on with the service brake pressure from the non-preferentially filled service brake circuit. Forces generated by the three active surfaces counteract a closing force in order to open or hold open the overflow valve.

Abstract: A vent valve made from a standard emergency brake valve portion. It includes an emergency portion body with an interface to be mated with the emergency portion interface of the pipe bracket. The body includes a casting with at least one cover and the casting including all the cast cavities and passages for an emergency portion. A vent valve selectively connects a first brake pipe port to a vent port on the body, A vent piston controls the vent valve and a discharge valve pneumatically controls the vent piston. An emergency piston is responsive to brake pipe pressure for controlling the discharge valve. The body does not include at least one of an inshot valve and an accelerated application valve.

Abstract: The present locomotive brake system includes a brake controller operable by an operator and a brake pipe vent valve. The brake controller includes an emergency output port which provides emergency pneumatic signal on the emergency output port when the brake controller is in an emergency position. The brake pipe vent valve includes a housing having brake pipe, emergency input and exhaust ports, and a first valve. The emergency output port is fluidly connected to the emergency input port. The first valve selectively connects the brake pipe port to the exhaust port when opened in response to an emergency signal on the brake pipe port and in response to an emergency signal on the emergency input port.

Abstract: A vent valve made from a standard emergency brake valve portion. It includes an emergency portion body with an interface to be mated with the emergency portion interface of the pipe bracket. The body includes a casting with at least one cover and the casting including all the cast cavities and passages for an emergency portion. A vent valve selectively connects a first brake pipe port to a vent port on the body, A vent piston controls the vent valve and a discharge valve pneumatically controls the vent piston. An emergency piston is responsive to brake pipe pressure for controlling the discharge valve. The body does not include at least one of an inshot valve and an accelerated application valve.

Abstract: A relay valve based accelerated brake pipe application and release system having an electronic control module. A source of fluid pressure is connected to a valve device for receiving and transmitting fluid pressure signals. The valve device is connected to an exhaust to atmosphere. An accelerator volume has a fluid connection to the valve device for storing a predetermined volume of fluid. A brake pipe transducer is electronically connected to the control module and has a fluid connection to the valve device for transmitting a first pressure signal to the control module. A cut-out solenoid valve is electronically connected to the control module and includes a fluid connection to the brake pipe transducer for receiving at least one of a cut-in and a cut-out signal. An emergency solenoid valve is electronically connected to the control module and has a fluid connection to the cut-out solenoid valve for receiving an emergency signal.

Abstract: A vent valve made from a standard emergency brake valve portion. It includes an emergency portion body with an interface to be mated with the emergency portion interface of the pipe bracket. The body includes a casting with at least one cover and the casting including all the cast cavities and passages for an emergency portion. A vent valve selectively connects a first brake pipe port to a vent port on the body, A vent piston controls the vent valve and a discharge valve pneumatically controls the vent piston. An emergency piston is responsive to brake pipe pressure for controlling the discharge valve. The body does not include at least one of an in shot valve and an accelerated application valve.

Abstract: A portable, single-car test unit for a railway freight brake control valve for manually executing pressure manipulations to evaluate the operating conditions of the control valve. The pipe bracket portion is connected to a brake pipe, an auxiliary reservoir, an emergency reservoir, a brake cylinder retaining valve and a brake cylinder each being connected to a respective fluid passageway. The test unit accesses the fluid passageways at access ports, respectively connected to each passageway. Valves are utilized in the test unit to manipulate the pressure in the fluid passageways and pressure gauges measure fluid pressure in the passageways. An operator records each pressure measurement and calculates and stores the differences between selected pairs of the pressure measurements as well as elapsed time data for the measurements.

Abstract: A device for control and monitoring of pressure in a system combines a conventional three pole pressure switch with the following additional features: (1) a lock mechanism with three influencing input factors and a single resulting output contact action, (2) a three pole thermal release device as one of the input factors, and (3) a remote control tripping device as another input factor, all integrated into a single, compact, modular unit. The thermal release device comprises a plurality of bimetals which sense electrical flow passing through the device, and which are mechanically connected to a locking mechanism to shut off current if the electrical flow reaches a predetermined maximum. If any of the three inputs activates the locking mechanism, the device must be reset by an operator.

Abstract: A portable, microprocessor controlled single-car test unit for a railway freight brake control valve for automatically executing pressure manipulations to evaluate the operating conditions of the control valve. The pipe bracket portion is connected to a brake pipe, an auxiliary reservoir, an emergency reservoir, a brake cylinder retaining valve and a brake cylinder each being connected to a respective fluid passageway. The test unit accesses the fluid passageways at access ports, respectively connected to each passageway. Valves are utilized in the test unit to manipulate the pressure in the fluid passageways and pressure transducers measure fluid pressure in the passageways. The pressure transducers are controlled by a computer having a microprocessor connected to an input output device. The computer records and stores each pressure measurement, and calculates and stores the differences between selected pairs of the pressure measurements as well as elapsed time data for the measurements.

Abstract: An emergency vent valve including a piston responsive to the differential pressure between the brake pipe and a control volume to open a vent valve to vent the brake pipe to atmosphere and includes an exhaust valve responsive to the differential pressure between brake pipe and control volume to connect the control volume to atmosphere through a service check and when the vent valve is opened through a second blow-down choke of a lesser rate which limits the exhausting of the control chamber. A choke valve connected to the piston connects the blow-down choke in series with the service choke when the vent valve becomes fully open.

Abstract: A railway car vent valve device having a nullifier valve that is selectively operable to disable the vent valve device during a single car test procedure in which the service stability of the car control valve is checked. The nullifier valve is automatically reset when the car brake pipe pressure drops below a predetermined value, such as occurs when the single car test apparatus is disconnected from the car brake pipe following completion of the single car test procedure.

Abstract: A valve assembly for use with spring-set air-release vehicle parking brakes comprises a particular arrangement of conventional components providing desired spring brake operational characteristics heretofore requiring costly, complex specially-designed units. The valve assembly typically employs a plurality of interconnected check valves in combination with pressure protection and quick release valves to provide the desired characteristics. These include a system whereby at startup pressurized air from the tractor fills the trailer reservoir tanks and the spring brake chambers simultaneously. The valve assembly also assures that if during tractor-trailer operation the supply air from the tractor is severed or otherwise lost, service brake air in the trailer reservoir tanks is retained at a sufficient pressure to provide adequate service brake operation.

Abstract: A railway car vent valve device having a bleed valve that is selectively operable to disable the vent valve device during a single car test procedure in which the service stability of the car control valve is checked. The bleed valve is automatically reset when the car brake pipe pressure drops below a predetermined value, such as occurs when the single car test apparatus is disconnected from the car brake pipe following completion of the single car test procedure.

Abstract: An accelerated application valve having a cyclic mode of operation during one phase of which a local quick service reduction of brake pipe pressure occurs and a steady state mode of operation during which a continuous local quick service reduction of brake pipe pressure is achieved. The specific mode of operation is dictated by a control signal that varies with the degree of service brake application called for, this control signal being the "breather" pressure at the ABD/ABDW Control Valve emergency portion.

Abstract: A brake control system having a vent valve device in which a control piston is effective to unseat a normally closed vent valve to provide rapid exhaust of brake pipe pressure to either propagate an emergency brake application in response to brake pipe pressure on one side of the piston being reduced at an emergency rate or to initiate an emergency brake application when pressure on the opposite side of the piston is increased by an auxiliary pilot valve connected to a second main reservoir at a higher pressure.

Abstract: An improved freight brake emergency valve device having improved stability against undesired emergency brake applications, without loss of emergency sensitivity. Flow regulator in the form of a valve and choke combination or a choke itself is employed between the quick action chamber and the chamber normally subject to quick action chamber pressure on the side of the emergency piston opposite brake pipe pressure. This has the effect of momentarily reducing the volume of quick action chamber pressure in order to achieve an intensified pressure reduction in response to initial deflection of the piston member sufficient to counteract a momentary, spurious brake pipe pressure fluctuation.

Abstract: A vent valve device having a pair of diaphragm-type piston members forming a pilot chamber therebetween. The one piston controls a vent valve via which brake pipe pressure is vented locally, while the other piston controls a pilot valve a control venting of the pilot chamber. A breather choke between the pilot chamber on one side of the other piston and a control chamber on the opposite side establishes a predetermined pressure differential thereacross only when brake pipe pressure supplied to the pilot chamber is reduced at an emergency rate to thereby actuate the other piston to a position opening the pilot valve. In addition, this other piston operates a cut-off valve to isolate the pilot chamber from brake pipe pressure so that the pilot valve quickly exhausts pilot chamber pressure.

Abstract: A continual type quick service valve adapted to be independently mounted on a railway car to provide local, supplemental venting of the car brake pipe pressure, as long as the brake pipe pressure continues to be reduced externally. This quick service venting of the brake pipe pressure is achieved utilizing a single piston actuated exhaust valve that is either cyclically-operated between open and closed states or is held open continuously depending upon the degree of brake application in effect. By selective tuning, the open duration of the exhaust valve can be made to exceed the duration the exhaust valve is closed during each cycle of operation or to remain open for the duration of the external brake pipe pressure reduction to achieve high operating efficiency.

Abstract: An improved freight brake emergency valve device providing improved stability against undesired emergency brake applications without degradation of emergency sensitivity. This is achieved, in one aspect of the invention, by introducing a spring force on the emergency piston as the piston approaches emergency position to thereby retard the piston momentum suffiently to allow a random brake pipe pressure fluctuation to dissipate. In another aspect of the invention, a choke and check valve are arranged to create a dashpot effect to retard piston momentum resulting from a random brake pipe pressure fluctuation.

Abstract: The acceleration apparatus for connection with a pilot operated compressed-air brake comprises a tap-off valve which vents the main air line or conduit at the beginning of the braking procedure. This tap-off valve is opened by an actuator or actuating mechanism via a disengageable intermediary member. By employing a rotationally symmetrical plunger or push rod which is pivoted into the operative position thereof by a spring and deflected by an interrupter piston, the construction of the disengageable intermediary member can be substantially simplified. The plunger or push rod possesses at the one end thereof a cam or pin and a substantially conical surface.

Abstract: A modulation valve device for governing pressure in a brake pipe has coaxial accelerating and releasing valves provided wherein accelerated application and release pistons are dovetailed together to reduce the size and the weight of the modulating device.

Abstract: An improved freight brake emergency valve providing improved stability against undesired emergency brake applications without degradation of emergency sensitiveity by increasing the "breathing" range of travel of the emergency piston to allow a momentary random brake pipe pressure fluctuation to dissipate, and by providing a volumetric chamber between the quick action chamber "breather" port connection at the slide valve/seat interface and the "breather" choke in order to obtain a momentary fast reduction of quick action chamber pressure to counteract a brake pipe pressure fluctuation during pressure equalization between the quick action chamber and the added volumetric chamber.

Abstract: A fluid brake control system for a railway train has control valves of the ABD type that have service valves that are modified to provide continuous quick service, thus eliminating the need for special accelerated application valves as currently used in ABDW control valves.

Abstract: A freight brake control valve device in which the emergency piston slide valve is arranged to incorporate, in conjunction with the conventional service stability function provided thereby, an accelerated service application function in which a continuous local venting of brake pipe pressure is provided to hasten propagation of service rates of brake pipe reduction. A preliminary flow restrictor in one flow path and a primary flow restrictor in a parallel flow path control the quick-action chamber "breathing" rate such that the emergency piston is stabilized against movement to emergency position, as long as the brake pipe pressure reduction does not exceed a service rate. Following a service application, the preliminary flow restrictor has the further function of maintaining "breathing" until after the local reduction of brake pipe pressure is cut off, thereby assuring positive movement of the emergency piston to its service lap position.

Abstract: A pulsating brake accelerating device for an indirectly operating air brake for rail vehicles has a pulsator (12), which is attached to the brake pipe (BP) via a jet (23). The pulsator (12) forms a mixed pressure from two pressures. One of the pressures is formed by the pressure of the brake pipe (BP) via a jet (23) and the other pressure is formed by pressure from a control chamber (QAC) via another jet. At every braking level the pulsator (12) drains mixed pressure pulses off into the atmosphere, while at the same time the brake pipe pressure and the control chamber pressure is lowered via the mixed pressure pulsator (12). The mixed pressure can consist of two valves (14, 15). The control element (4) of the brake accelerator unit can be the emergency brake piston, which monitors several valves, one of which is the pulsator-excitation valve (8).

Abstract: A pulsating brake accelerating device for an indirectly operating air brake for rail vehicles has a pulsator (12), which is attached to the brake pipe (BP) via a jet (23). The pulsator (12) forms a mixed pressure from two pressures. One of the pressures is formed by the pressure of the brake pipe (BP) via a jet (23) and the other pressure is formed by pressure from a control chamber (QAC) via another jet. At every braking level the pulsator (12) drains mixed pressure pulses off into the atmosphere, while at the same time the brake pipe pressure and the control chamber pressure is lowered via the mixed pressure pulsator (12). The mixed pressure can consist of two valves (14, 15). The control element (4) of the brake accelerator unit can be the emergency brake piston, which monitors several valves, one of which is the pulsator-excitation valve (8).

Abstract: A service brake accelerator for indirect compressed-air brakes on railway vehicles includes a control piston which is loaded by the pressure in the main airpipe against the pressure in a reference pressure chamber and which controls a shutoff valve between the main airpipe and a piston chamber, a first outlet valve for the main airpipe and a second outlet valve for the piston chamber. Through appropriate dimensioning of the valve strokes (a,b), upon movement of the control piston out of its rest position the shutoff valve is closed first, and simultaneously or later the first outlet valve is opened and only subsequently the second outlet valve is opened. A valve piston arranged coaxially with the control piston is loaded by the pressure in the piston chamber and the force of a spring.On its other side, the valve piston is acted upon by the reference pressure over a partial area, but with the air vent valve open it is acted upon by the reference pressure over its entire area.

Abstract: A fluid pressure brake control system of the direct release type for a freight locomotive comprises a first pipe bracket having a manually controllable automatic brake valve device connected thereto on one side for governing fluid brake control pressure in a train pipe, and a manually controllable independent brake valve device is connected on another side of the bracket for governing brakes of the locomotive independent of brakes of freight cars in a train. There is a locomotive brake control valve device comprising a second pipe bracket having a service valve portion secured to one side thereof corresponding to a service valve portion such as is conventionally used on freight car control valve devices. A quick release and emergency valve portion is secured to another side of the second pipe bracket for governing emergency brake pressure and for governing independent direct release of brakes of a locomotive in response to actuation of the manually controllable independent brake valve device.

Abstract: An accelerator for control valves, particularly for triple pressure control valves (3) of pneumatic brake systems of rail vehicles, having a pick-up accelerator (30) and a transfer chamber (40) as well as a service brake accelerator (52), the service brake accelerator (52) having a reference pressure chamber (55) which is connected to the transfer chamber (40) of the pick-up accelerator, the transfer chamber having a bleeder nozzle which is not open at all times. As a result, the service brake accelerator (52) is activated only during braking operations, while the reference pressure chamber (55) is protected from filling strokes, the volumes which are in continuous connection with the air main (1) are reduced, and the air consumption is lowered, especially during brake release operations.

Abstract: A service brake accelerator having a line chamber (3) connected to the main air supply line (1) and a reference pressure chamber (6) connected to the line chamber via a nozzle (7). The line chamber is separated from the reference pressure chamber by a diaphragm piston (5) which is biased by a spring (10) against a valve seat (9) projecting into the reference pressure chamber and restricting a nozzle opening (23) to the inner chamber (24) of a second valve seat (20). A second diaphragm piston (17) is biased against this second valve seat by a spring (21). The space (16) surrounding the second valve seat can be connected, partly throttled, via a nozzle (14), to the line chamber by way of a shut-off valve (12, 13) which opens laterally of the reference pressure chamber upon overbalancing pressure upon the first diaphragm piston; this space is always open to atmosphere via a further nozzle (25). The accelerator operates cyclically and has a safe, stable neutral position between its work cycles and rest position.

Abstract: A brake accelerator is operable sequentially upon each successive braking stage over the service application range of brake line pressure reductions and is employed with a single release brake control valve of an indirectly acting compressed air brake for railway vehicles. The control valve has a service brake portion and an emergency brake portion provided with a emergency brake piston one side of which is subjected to brake line pressure and the other side is subjected to auxiliary chamber pressure . The accelerator has a main piston which operates an inlet valve to connect the accelerator to the brake line. The main piston which is also subjected on one side to brake line pressure and the other side to auxiliary chamber pressure is moved to a service position upon an application of the brakes to open the inlet valve and connect a control piston with the brake line such that the control piston is subjected on both sides to brake line pressure.

Abstract: A spring-loaded brake device particularly for railway vehicles has a brake valve to control the pressure in a brake line and spring-loaded brake cylinders that can be subjected to the action of pressure in the brake line against the force of a loading spring. At least one venting valve is connected to the brake line and the venting valve comprises a rapid acting valve which is controlled by pressure in the brake line to open a venting passage from the brake line to the atmosphere only when the pressure in the brake line is lowered from a brake release level to a level at which the brake cylinder makes braking contact. This venting passage is otherwise closed. The rapid acting valve thus removes air under pressure from the spring-loaded brake cylinders and flows this air to the atmosphere only at the beginning of a braking operation. Upon further application of the brakes the rapid acting valve has no effect and brake pressure is controlled by the brake valve.

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 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: This invention relates to a railway vehicle continual quick service valve device that embodies two abutments normally subject on their respective opposite sides of the pressure in a train brake pipe and in a control chamber. Upon a reduction of brake pipe pressure on one side of these abutments, one abutment operates a valve to release fluid under pressure from the brake pipe and the brake pipe side of the other abutment to atmosphere whereupon this other abutment operates a valve that releases fluid under pressure from the control chamber and the control chamber side of both abutments to atmosphere. These abutments then operate their respective valves to cut off venting of fluid under pressure from the brake pipe and the control chamber to atmosphere. If the reduction of brake pipe pressure on the one side of the one abutment continues, the abovedescribed cycle reoccurs so long as fluid under pressure is released from the brake pipe.

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: An automatic brake release valve in the form of a normally open pressure relief venting structure for air operated vehicular brakes and the like, wherein atmospheric air is vented into the closed brake system intermediate the air brake actuating valves and the brake chambers actuated thereby. This venting valve structure relieves any pressure build-up which occurs as a result of brake valve leakage, since any increase in pressure in this part of the system closes the exhaust valves and actuates the brakes. So that normal brake function is maintained, the venting valve structure closes on a predetermined pressure rise. Thus, when the brakes of the vehicle are applied, a limited amount of air will escape from the system, until the predetermined valve closing pressure is reached, and during this air escape period, water condensate is exhausted from the system automatically, while providing maximum brake efficiency.

Abstract: This invention relates to a railway vehicle continual quick service valve device that embodies two abutments normally subject on their respective opposite sides of the pressure in a train brake pipe and in a control chamber. Upon a reduction of brake pipe pressure on one side of these abutments, one abutment operates a valve to release fluid under pressure from the brake pipe and the brake pipe side of the other abutment to atmosphere whereupon this other abutment operates a valve that releases fluid under pressure from the control chamber and the control chamber side of both abutments to atmosphere. These abutments then operate their respective valves to cut off venting of fluid under pressure from the brake pipe and the control chamber to atmosphere. If the reduction of brake pipe pressure on the one side of the one abutment continues, the above-described cycle reoccurs so long as fluid under pressure is released from the brake pipe.

Abstract: A brake accelerator has a control chamber connected through a throttle orifice to a brake line. The brake system includes a control valve in which is an emergency brake piston one side of which is subjected to brake line pressure and the other side of which is subjected to pressure in the control chamber. The emergency brake piston, as a function of a pressure drop in the brake line, opens a brake line outlet valve so that air flows from the brake line through an inlet valve. The inlet valve is held by a control piston in its open position at the start of a pressure drop in the brake line and the air is flowed into a chamber to form a control pressure.

Abstract: An accelerator device for a three-pressure control valve of an air brake system on a railway vehicle has a control piston one side of which is subjected to air line pressure and the other side to pressure in a control chamber such that when the pressure in the control chamber predominates the control piston opens an accelerator valve between the air line pressure and a valve chamber. A monitor valve is between the valve chamber and a transfer chamber which continuously communicates to the atmosphere through a throttle orifice. A first piston operates the monitor valve and is subjected in the closing direction of the monitor valve to the action of braking pressure against the effect of a spring force.

Abstract: In a proportioning type control valve device in which a piston valve assemblage is actuated to service position in accordance with a differential between brake pipe and control reservoir pressures on opposite sides of an actuating piston abutment forming a part of the piston valve assemblage, there is provided on the control reservoir side of the piston abutment a bellows device that is normally held under compression by the presence of control reservoir fluid pressure so as to be normally disengaged from the piston and engageable therewith only in the absence of control reservoir pressure to serve as the reference against which reductions in brake pipe pressure are measured to establish the actuating force on the piston abutment. When disengaged from the piston abutment under the influence of the control reservoir pressure, the bellows holds a control spring housed within the bellows under compression.

Abstract: A vehicle air brake system includes spring set air released parking brakes to which air is supplied through a pressure holding valve which maintains the air chambers of the parking brakes at a predetermined pressure even though the air brake system may be at operating pressures substantially lower than the predetermined pressure. When the air pressure in the air brake system falls below operational levels, the pressure holding valve responds to release the air from the parking brake chambers.

Abstract: An upgraded railway freight car brake control valve device comprises a novel emergency valve portion that embodies therein a plurality of simple and inexpensive poppet valves and a spool-type valve which valves replace yet perform the same functions heretofore performed by more expensive slide-type valves which slide valves, and the flat seats upon which they slide as they are shifted from one position to another, in their manufacture require a considerable amount of accurate machining thus increasing the cost of the brake control valve device of which they are an important part.

Abstract: A brake accelerator for drawing off air from the brake line of an air brake system for railway vehicles has a piston one side of which is subjected to air pressure in the brake line and the other side is subjected to a control pressure in an expansion chamber connected to the brake line through a throttle opening. A first valve is in a connection between the brake line and a pressure accumulation chamber connected to the atmosphere through a second throttle opening. The first valve is actuated by the first piston when the control pressure exerted on the first piston is predominant. A second valve opens subsequently to the first valve and is located in a connection leading from the expansion chamber through a throttle opening to the atmosphere. The second valve is actuated by a second piston loaded by the pressure in the pressure accumulation chamber in the direction to open the second valve against the force of a spring urging the second valve into its closed position.

Abstract: A fluid brake control system is disclosed having an improved emergency application and stability control device for use in association with a brake control pipe, emergency and auxiliary fluid reservoirs, a first quick action chamber, a brake cylinder, and emergency and service control valves. An improved emergency application and stability control valve is provided comprising a housing containing a differential abutment subject to actuation axially by differences in fluid pressures in respective brake pipe pressure and quick action control pressure chambers on opposite sides of the abutment. The control device has at least one ball poppet type valve on each side of the abutment that is spring biased toward a closed position and has an operating push rod longitudinally disposed between the associated valve and the abutment. The poppet valve on one side of the abutment is opened by movement of the abutment in one direction for permitting application of fluid from the emergency reservoir to the brake cylinder.

Abstract: A fluid brake control system is disclosed for having an improved brake cylinder release control device for use in association with a brake control pipe, a fluid reservoir, and a service valve. The control device has a housing containing a differential abutment subject to actuation from a normal position by differences in pressure between a release spring in a chamber on one side of the abutment and pressure selectively applied to the abutment in another chamber on the opposite side of the abutment. A plurality of poppet type valves operated by longitudinal push rods connected by a bridge are provided in the chamber on each side of the abutment, the bridge being actuated at a midpoint by the abutment.

Abstract: An inexpensve emergency valve device embodies a cycling-type continual quick service valve operative by an abutment, subject on its respective opposite sides to the pressure in a train brake pipe and in a quick action chamber, in response to a service rate of reduction of the pressure of the fluid in a train brake pipe to repeatedly vent and supply fluid under pressure from and to a quick service volume disposed on one side of a diaphragm-type valve that is operatively responsive to the venting of fluid under pressure from this volume to effect the release of fluid under pressure from the quick action chamber to atmosphere at a rate faster than a service rate to cause joint cyclic operation of the continual quick service valve and the diaphragm valve to successively supply fluid under pressure from the brake pipe to and thereafter release fluid under pressure from the quick service volume at a certain rate and from the quick action chamber at a faster rate so long as fluid under pressure is released from the