US1327968A - Air-brake-controlling mechanism - Google Patents

Air-brake-controlling mechanism Download PDF

Info

Publication number
US1327968A
US1327968A US67374A US6737415A US1327968A US 1327968 A US1327968 A US 1327968A US 67374 A US67374 A US 67374A US 6737415 A US6737415 A US 6737415A US 1327968 A US1327968 A US 1327968A
Authority
US
United States
Prior art keywords
valve
brake
air
engineers
reservoir
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US67374A
Inventor
Thomas W Scott
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AMERICAN TRAIN CONTROL CO
Original Assignee
AMERICAN TRAIN CONTROL CO
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by AMERICAN TRAIN CONTROL CO filed Critical AMERICAN TRAIN CONTROL CO
Priority to US67374A priority Critical patent/US1327968A/en
Application granted granted Critical
Publication of US1327968A publication Critical patent/US1327968A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60TVEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T7/00Brake-action initiating means
    • B60T7/12Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger
    • B60T7/128Self-acting brakes of different types for railway vehicles
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60TVEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/24Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being gaseous
    • B60T13/26Compressed-air systems
    • B60T13/40Compressed-air systems indirect, i.e. compressed air booster units indirect systems

Definitions

  • This invention relates to an improved air brake controlling mechanism, and is especially designed to cooperate with train-controlling mechanism of the automatic-stop type wherein the vehicle is automatically stopped in case the engineer or motorman proceeds in disregard of danger signals or dangerous conditions ahead.
  • the present invention has to do, more particularly, with the operation of the airbrakes and one of its main objects is to provide an improved mechanism whereby after the automatic stop mechanism has been actuated to apply the brakes the air-supply from the main reservoir shall be cut-ofi' so that the train line cannot be recharged by any manipulation on the part of the engineer or motorman of the engineers valve in the cab until the train has been brought to a stop.
  • Another object of the invention is to provide an electro-pneumatic valve mechanism that is interposed in the air-brake system between the main-reservoir and the engineers valve, which pneumatic valve is itself controlled through a switch of a ramp-rail contact-shoe whereby to automatically cutoff communication between the main-reservoir and engineers valve when an automaticv stop operation takes place.
  • a further object of the invention is to combine with an air-brake apparatus, an electro-pneumatic valve to effect an automatic operation of the brakes, independ ently of the engineers brake valve an electro-pneumatic valve to control the passage of air from the main reservoir to the engineers valve and a shoe-operated switch to control the two electro-pneumatic valves whereby when one valve efi'ects an automatic operation of the brakes the other valve will cut-ofl the reservoir supply to the engineers valve and thus prevent recharging of the train line through the engineers valve.
  • FIG. 1 diagrammatically illustrates the apparatus.
  • Fig. 2 shows a sectional view of the trainline vent apparatus.
  • Fig. 3 shows in section, the device that controls the vent apparatus.
  • Fig. 4 is a sectional detail of the reservoir-pressure control device.
  • the numeral 1 designates the main reservoir; 2, the engineers brake-valve and 3 the train line or brake pipe, all of the well-known air-brake equipment, of which the train line or brake pipe extends throughout the lengthof the train and has connections, as usual, through triple valves to the auxiliary reservoir and brake cylinders on the various cars, which triple valves, auxiliary-reservoirs and brake cylinders it is deemed unnecessary to illustrate.
  • pipe connect1ons 4, 5 and 6, are shown, between the;
  • main-reservoir 1 and engineers brake valve another pipe 10 extends from said valve casing and connects with pipe 6, leading to the engineers valve, thus pipes 8 and 10, provide a branch around the normally closed cock 7, so that main-reservoir air-pressure may normally pass through the electro-pneumatic valve to the engineers brake valve.
  • the electro pneumatic Valve casing has a passage 11, with which the pipe 8, connects and a port 12, is provided at the inner end of this passage through which the fluid pressure may pass to a chamber 13.
  • the pipe 10 then leads from the chamber 13, to pipe 6.
  • the casing Directly beneath the port 12, the casing has an opening into which a valve-rod 14, projects and said rod has a narrow stem 15, that projects across the chamber; passes through the port 12, and carries a valve 16, at its outer end.
  • This valve 16 is thus retained in the pasage 11, over the port 12, but is normally raised so as to leave said port uncovered and allow air from the main reservoir and pipe 8, to pass through the chamber 13 to pipe 10.
  • the valve rod 14 has an armature head 17, at is lower end which latter is normally held up by the electro-inagnet 18, so as to keep the rod 14, and .the valve 16, at its upper end elevated as long as the magnet is energized.
  • a resetting stem 19 is providedbeneath the armature head 17, whereby afhand-resetting of the arma ture may be effected after the magnet has been deenergized.
  • electro-pneumatic valves employed in the operation of this invention are preferably located on the vehicle where they are inaccessible from the cab so that it is preferably necessary to bring the vehicle to a full stop in order to gain access to these valves to reset them after they have been automatically operated.
  • the engineers-brake valve and the train line or brake pipe 3, are connected by a pipe 20, in which a cut-out cock 21, is usually placed, which cock, however is nor-- mally open.
  • the apparatus also includes an electropneumatic valve mechanism whereby to effect an automatic operation of the brakes independently of the engineers valve which will now be briefly described.
  • a valve casing 22 has a passage 23, with a-port 24, attheinner end thereof that opens into a chamber 25, and a pipe 26, connects the said passage 23, with the pipe 6, that supplies the main reservoir air.
  • a normally-open valve 27, is provided in the passage '23, over the port 24, and said valve carried on a stem 28, that projects from the end of a, valve-rod 29.
  • This valve-rod normally extends across and closes a passage 30, that leads to the atmosphere so that fluid pressure in the chamber 25,- will be prevented normally from venting to the atmosphere through the passage 30.
  • the rod passes through an I electromagnet 31, and carries an armaturehead 32, at its lower end so that as long as the magnet is energized the rod will be held up tokee'p valve 27, unseated and to close passage 30.
  • a resetting stem 33 is also provided for the armature head 32, to reset the same after the magnet has been operated.
  • A- pipe 34 extends from the chamber 25, and, enters a chamber 35, in a casing and at the upper side of a diaphragm 36. Below the diaphragm the casing has another chamber 37, in which a valve 38, is located.
  • This valve is carried by a stem 39, that is attached to anclnioves with the diaphragm and the valve normally closes escape ports 40, that extend through the casing and also normally closes a port 41, at the inner end of a pipe 42, which pipe connects with the of the diaphragm 36, will hold stem 39 and valve 38, down on port 41, and against the lesser train-pipe pressure so this latter pressure cannot normally escape through the ports 40.
  • the vehicle is provided with a contact shoe 43, which. has arod that carries or operates a shoe-switch 44, a cur rent supply, such for example as a battery 45, is provided on the vehicle and a connec- *tion 46, extends from the positive side of the battery to one shoe-switch contact 47, while from the other switch contact 48,- a wire or connection 49, leads to and connects with a binding post 50, of the electro-magnet 31.- The other binding post 51,- of this magnet has a return connection by wires 52, 53 and 54, to the negative side of the bat tery or current supply 45.
  • electro-magnet 18 is energized from the vehicle current supply by a wire 55, that branches from wire' 49 and is engaged with one binding post 56', and a return connection from post 57, and wire 58, to wire 53.
  • the contact shoe 43 is posi tioned on the vehicle so it may engage ramp rails that are located at spaced-apart inter vals along the trackway, and in the system in which the present invention is to form a part the ramp rails are connected with or disconnected from a track-way current sup ply (not deemed necessary to illustrate in this case) according to the safeor dangerous conditions ahead.
  • the contact shoe 43 engages an energized ramp it will pick up a current from that ramp and send the picked-up curthis art.
  • the shoe 43 engages a deenergized ramp rail it will not pick up a current and during its upward movement in riding up onto the ramp rail it will move shoe switch 44, so as to interrupt or break the connections in the normal vehicle circuit across contacts 44: and 48, thus cutting off both electro-magnets 18 and 31 from the vehicle current supply 45, and deenergizing those magnets.
  • valverod 29 When magnet 31, is thus denergized valverod 29, will drop and seat valve 27, to cutofl' the inlet of reservoir pressure and at the same time said rod 29, will uncover the passage 30, to the atmosphere so that the pressure in chamber 25, pipe 34, and chamber 35, over the diaphragm 36, will be vented to the atmosphere.
  • the venting of the chamber 35, at the upper side of the diaphragm 36, will produce a preponderance of pressure on the valve 38, from the train line, consequently this latter valve will move up and the train line pressure will then escape from port 41, out through vent port 40, and by this reduction in the train line pressure cause an application of the air-brakes, just the same as though the venting had taken place at the engineers brake valve.
  • valve rod 14 will drop and seat valve 16, on port 12, and thus prevent main reservoir air pressure from flowing through pipe 8 to the engineers brake valve; therefore without main-reservoir pressure, the engineer cannot, by any manipulations whatever of the engineers valve, recharge his train line to release his brakes and he must bring'his train to a stop. Upon stopping his train, the engineer can then gain access to the reset devices 19 and 33, and resetthe electro-magnets in order that he may reestablish the connection between the main-reservoir and en neers valve, whereupon the brakes can e released.
  • an air-brake controlling mechanism the combination with an air brake apparatus including a reservoir, a train line and an engineers valve, of connections for supply ing air from the reservoir to the train line only through the engineers valve; one electro-pneumatic means entirely separate and independent of all the devices of the engineers valve for effecting an automatic application of thebrakes, and a second electro-pneumatic means for cutting ofi" the supply of all air to the train line to prevent a release of the brakes by the engineer.
  • an air-brake controlling mechanism the combination with an air-brake apparatus including a reservoir, a train line and an engineers valve, of connections for supplying air from the reservoir to the train line only through the engineers valve; a Valve controlling the escape of air from the train line to the atmosphere; connections from one side of said valve to the train line said connections being entirely independent of the engineers valve; connections from the other side of said valve to the reservoir to hold the valve closed by reservoir pressure and these latter connections also being entirely independent of the engineers valve; an electro-pneumatic valve in said latter connections and a second electro-pneumatic valve for cutting oil all air to the train line to prevent a release of the brakes by the engineers.

Description

T. W. SCQTT.
AIR am: commune macumsm v APPLICATION FILED DECJL IBIS- RENEWED NOV. l2, l9l9. "1,327,968, Patented Jan. 13, 1920.
Patented J an. 13, 1920.
2 SHEETS-SHEET 2.
gwuentoz attocmgq UNITE s'rs Arr OFFICE.
THOMAS W. SCOTT, OF BALTIMORE, MARYLAND, ASSIGNOR TO THE AMERICAN'TRAIN CONTROL (30., OF BALTIMORE, MARYLAND, A CORPORATION OF MARYLAND.
AIR-BRAKE-CONTROLLING MECHANISM.
Application filed December 17, 1915, Serial No. 67,374.. Renewed November 12, 1919. Serial No. 337,621.
To all whom it may concern:
Be it known that I, THOMAS W. Soo'r'r, a citizen of the United States, residing at Baltimore, in the State of Maryland, have invented certain new and useful Improvements in Air-Brake-Controlling Mechanism, of which the following is a specification.
This invention relates to an improved air brake controlling mechanism, and is especially designed to cooperate with train-controlling mechanism of the automatic-stop type wherein the vehicle is automatically stopped in case the engineer or motorman proceeds in disregard of danger signals or dangerous conditions ahead.
The present invention has to do, more particularly, with the operation of the airbrakes and one of its main objects is to provide an improved mechanism whereby after the automatic stop mechanism has been actuated to apply the brakes the air-supply from the main reservoir shall be cut-ofi' so that the train line cannot be recharged by any manipulation on the part of the engineer or motorman of the engineers valve in the cab until the train has been brought to a stop.
Another object of the invention is to provide an electro-pneumatic valve mechanism that is interposed in the air-brake system between the main-reservoir and the engineers valve, which pneumatic valve is itself controlled through a switch of a ramp-rail contact-shoe whereby to automatically cutoff communication between the main-reservoir and engineers valve when an automaticv stop operation takes place.
A further object of the invention is to combine with an air-brake apparatus, an electro-pneumatic valve to effect an automatic operation of the brakes, independ ently of the engineers brake valve an electro-pneumatic valve to control the passage of air from the main reservoir to the engineers valve and a shoe-operated switch to control the two electro-pneumatic valves whereby when one valve efi'ects an automatic operation of the brakes the other valve will cut-ofl the reservoir supply to the engineers valve and thus prevent recharging of the train line through the engineers valve.
Specification ofLetters Patent.
Patented Jan. 13, 1920.
The drawings illustrate the invention, wherein,-
Figure 1, diagrammatically illustrates the apparatus.
Fig. 2, shows a sectional view of the trainline vent apparatus.
Fig. 3, shows in section, the device that controls the vent apparatus. 1
Fig. 4, is a sectional detail of the reservoir-pressure control device.
By referring to the drawing it will be noted that the numeral 1, designates the main reservoir; 2, the engineers brake-valve and 3 the train line or brake pipe, all of the well-known air-brake equipment, of which the train line or brake pipe extends throughout the lengthof the train and has connections, as usual, through triple valves to the auxiliary reservoir and brake cylinders on the various cars, which triple valves, auxiliary-reservoirs and brake cylinders it is deemed unnecessary to illustrate.
In the present illustration, pipe connect1ons 4, 5 and 6, are shown, between the;
main-reservoir 1 and engineers brake valve another pipe 10, extends from said valve casing and connects with pipe 6, leading to the engineers valve, thus pipes 8 and 10, provide a branch around the normally closed cock 7, so that main-reservoir air-pressure may normally pass through the electro-pneumatic valve to the engineers brake valve.
'The electro pneumatic Valve casing, briefly stated, has a passage 11, with which the pipe 8, connects and a port 12, is provided at the inner end of this passage through which the fluid pressure may pass to a chamber 13. The pipe 10, then leads from the chamber 13, to pipe 6. Directly beneath the port 12, the casing has an opening into which a valve-rod 14, projects and said rod has a narrow stem 15, that projects across the chamber; passes through the port 12, and carries a valve 16, at its outer end.
This valve 16, is thus retained in the pasage 11, over the port 12, but is normally raised so as to leave said port uncovered and allow air from the main reservoir and pipe 8, to pass through the chamber 13 to pipe 10.
The valve rod 14, has an armature head 17, at is lower end which latter is normally held up by the electro-inagnet 18, so as to keep the rod 14, and .the valve 16, at its upper end elevated as long as the magnet is energized.
In the present instance a resetting stem 19, is providedbeneath the armature head 17, whereby afhand-resetting of the arma ture may be effected after the magnet has been deenergized.
In practice the electro-pneumatic valves employed in the operation of this invention are preferably located on the vehicle where they are inaccessible from the cab so that it is preferably necessary to bring the vehicle to a full stop in order to gain access to these valves to reset them after they have been automatically operated.
The engineers-brake valve and the train line or brake pipe 3, are connected by a pipe 20, in which a cut-out cock 21, is usually placed, which cock, however is nor-- mally open.
The apparatus also includes an electropneumatic valve mechanism whereby to effect an automatic operation of the brakes independently of the engineers valve which will now be briefly described.
"A valve casing 22, has a passage 23, with a-port 24, attheinner end thereof that opens into a chamber 25, and a pipe 26, connects the said passage 23, with the pipe 6, that supplies the main reservoir air. A normally-open valve 27, is provided in the passage '23, over the port 24, and said valve carried on a stem 28, that projects from the end of a, valve-rod 29.
This valve-rod normally extends across and closes a passage 30, that leads to the atmosphere so that fluid pressure in the chamber 25,- will be prevented normally from venting to the atmosphere through the passage 30. The rod passes through an I electromagnet 31, and carries an armaturehead 32, at its lower end so that as long as the magnet is energized the rod will be held up tokee'p valve 27, unseated and to close passage 30. A resetting stem 33, is also provided for the armature head 32, to reset the same after the magnet has been operated.
A- pipe 34, extends from the chamber 25, and, enters a chamber 35, in a casing and at the upper side of a diaphragm 36. Below the diaphragm the casing has another chamber 37, in which a valve 38, is located. This valve is carried by a stem 39, that is attached to anclnioves with the diaphragm and the valve normally closes escape ports 40, that extend through the casing and also normally closes a port 41, at the inner end of a pipe 42, which pipe connects with the of the diaphragm 36, will hold stem 39 and valve 38, down on port 41, and against the lesser train-pipe pressure so this latter pressure cannot normally escape through the ports 40.
Under normal running conditions, both electro- magnets 18 and 31, will be energized through circuits that will. now be explained.
In automatic stop devices of the character herein referred to, the vehicle is provided witha contact shoe 43, which. has arod that carries or operates a shoe-switch 44, a cur rent supply, such for example as a battery 45, is provided on the vehicle and a connec- *tion 46, extends from the positive side of the battery to one shoe-switch contact 47, while from the other switch contact 48,- a wire or connection 49, leads to and connects with a binding post 50, of the electro-magnet 31.- The other binding post 51,- of this magnet has a return connection by wires 52, 53 and 54, to the negative side of the bat tery or current supply 45.
In a similar manner electro-magnet 18, is energized from the vehicle current supply by a wire 55, that branches from wire' 49 and is engaged with one binding post 56', and a return connection from post 57, and wire 58, to wire 53.
It will thus be seen that as long asthe contact shoe 43, is down and shoe switch 44', is closed, both electro- magnets 18 and 31, will be energized, and the control of the brakes will be effected as usual through the manipulations of the engineers brake valve 2.
In practice the contact shoe 43, is posi tioned on the vehicle so it may engage ramp rails that are located at spaced-apart inter vals along the trackway, and in the system in which the present invention is to form a part the ramp rails are connected with or disconnected from a track-way current sup ply (not deemed necessary to illustrate in this case) according to the safeor dangerous conditions ahead.
If therefore, the contact shoe 43, engages an energized ramp it will pick up a current from that ramp and send the picked-up curthis art. On the other hand, if the shoe 43, engages a deenergized ramp rail it will not pick up a current and during its upward movement in riding up onto the ramp rail it will move shoe switch 44, so as to interrupt or break the connections in the normal vehicle circuit across contacts 44: and 48, thus cutting off both electro- magnets 18 and 31 from the vehicle current supply 45, and deenergizing those magnets.
When magnet 31, is thus denergized valverod 29, will drop and seat valve 27, to cutofl' the inlet of reservoir pressure and at the same time said rod 29, will uncover the passage 30, to the atmosphere so that the pressure in chamber 25, pipe 34, and chamber 35, over the diaphragm 36, will be vented to the atmosphere. The venting of the chamber 35, at the upper side of the diaphragm 36, will produce a preponderance of pressure on the valve 38, from the train line, consequently this latter valve will move up and the train line pressure will then escape from port 41, out through vent port 40, and by this reduction in the train line pressure cause an application of the air-brakes, just the same as though the venting had taken place at the engineers brake valve. Thus we get an automatic application ofthe brakes independently of the engineers brake valve.
As electro-magnet 18, is de'nergized, valve rod 14, will drop and seat valve 16, on port 12, and thus prevent main reservoir air pressure from flowing through pipe 8 to the engineers brake valve; therefore without main-reservoir pressure, the engineer cannot, by any manipulations whatever of the engineers valve, recharge his train line to release his brakes and he must bring'his train to a stop. Upon stopping his train, the engineer can then gain access to the reset devices 19 and 33, and resetthe electro-magnets in order that he may reestablish the connection between the main-reservoir and en neers valve, whereupon the brakes can e released.
Having described my invention what I claim is,-
1. In an air-brake controlling mechanism the combination with an air brake apparatus including a reservoir, a train line and an engineers valve, of connections for supply ing air from the reservoir to the train line only through the engineers valve; one electro-pneumatic means entirely separate and independent of all the devices of the engineers valve for effecting an automatic application of thebrakes, and a second electro-pneumatic means for cutting ofi" the supply of all air to the train line to prevent a release of the brakes by the engineer.
2. In an air-brake controlling mechanism the combination with an air-brake apparatus including a reservoir, a train line and an engineers valve, of connections for supplying air from the reservoir to the train line only through the engineers valve; a Valve controlling the escape of air from the train line to the atmosphere; connections from one side of said valve to the train line said connections being entirely independent of the engineers valve; connections from the other side of said valve to the reservoir to hold the valve closed by reservoir pressure and these latter connections also being entirely independent of the engineers valve; an electro-pneumatic valve in said latter connections and a second electro-pneumatic valve for cutting oil all air to the train line to prevent a release of the brakes by the engineers. In testimony whereof I aflix my'signature in the presence of two witnesses.
THOMAS W. SCOTT. Witnesses:
CHARLES B. MANN, Jr., BERTHA K. WALTER.
US67374A 1915-12-17 1915-12-17 Air-brake-controlling mechanism Expired - Lifetime US1327968A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US67374A US1327968A (en) 1915-12-17 1915-12-17 Air-brake-controlling mechanism

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US67374A US1327968A (en) 1915-12-17 1915-12-17 Air-brake-controlling mechanism

Publications (1)

Publication Number Publication Date
US1327968A true US1327968A (en) 1920-01-13

Family

ID=22075572

Family Applications (1)

Application Number Title Priority Date Filing Date
US67374A Expired - Lifetime US1327968A (en) 1915-12-17 1915-12-17 Air-brake-controlling mechanism

Country Status (1)

Country Link
US (1) US1327968A (en)

Similar Documents

Publication Publication Date Title
US1092141A (en) Electropneumatic brake apparatus.
US1327968A (en) Air-brake-controlling mechanism
US2165999A (en) Fluid pressure brake
US2147297A (en) Electropneumatic brake equipment
US3545816A (en) Electrically assisted automatic air brake for trains
US363463A (en) Method of and apparatus for operating pressure or vacuum brakes
US1230083A (en) Electropneumatic valve for air-brakes.
US1090806A (en) Automatic air-brake control for railways.
US1644551A (en) Train-control device
US1558649A (en) Electropneumatic brake
US1318925A (en) Controlling mechanism for air-brakes.
US2065209A (en) Electro-pneumatic brake
US1439482A (en) Train-controlling mechanism
US902184A (en) Electropneumatic brake.
US1622430A (en) Electropneumatic brake
US696264A (en) Automatic retaining-valve for use in automatic fluid-pressure brake systems.
US811064A (en) Air-brake.
US1240796A (en) Air-brake-controlling mechanism.
US1991890A (en) Combined fluid pressure brake and signal system
US2256262A (en) Train sanding control device
US1976846A (en) Electropneumatic brake
US1173673A (en) Electropneumatic air-brake system.
US2575946A (en) Fluid pressure brake equipment
US1492336A (en) Vent-control valve for train-controlling mechanisms
US2661246A (en) Fluid pressure brake apparatus