US2563075A - Brake system for amusement park rides - Google Patents

Description

W. E. SQHMHDT BRAKE SYSTEM FOR AMUSEMENT PARK RIDES Filed Feb. 21, 1947 3 $heets-Sheet l INVENTOR,

W. B. SCHMIDT BRAKE SYSTEM FOR AMUSEMENT PARK RIDES 3 Sheets-Sheet 2 Filed Febq 21, 1947 Aug. 7 31% W. scHMmT I BRAKE SYSTEM FOR AMUSEMENT PARK RIDES 3 Sheets-Sheet 5 Filed Feb. 21. 1947 Patented Aug. 7, 1951 oFFlcE BRAKE SYSTEM FOR AMUSEMENT PARK 7 moss William B. Schmidt, Chicago, Ill. Application February 21, 1947, Serial No. 730,050

- 4 Claims.

This invention relates to safety brakes for an amusement park ride and has for its principal object the provision of a new and improved device of this kind.

It is a main object of the invention to provide in an amusement park ride a fluid pressure operated brake system that can be controlled from a central point by electromagnetic devices manually controlled by an operator.

Another object of the inventionis to provide a is away from the people thereon so that his attention will not be distracted from his work.

Still another'object of the invention is to provide in an amusement park ride, a brake system composed of standard parts that are readily available on the open market at low cost.

A still further object of the invention is to provide in an amusement park ride, a fluid pressure brake system that can be operated rapidly and positively with a minimum of power, thereby speeding up the ride with safety and at low cost.

Further objects of the invention not specifically mentioned here will be apparent from the detailed description and claims which follow, reference being had to th accompanying drawings in which a preferred embodiment of the invention is shown by Way of example and in which:

Fig. 1 is a plan view of the platform section'of an amusement park ride trackway showing the location of the braking mechanisms thereon;

Fig. 2 is a front elevational view of the control panel of the brake system;

Fig. 3 is an elevational view of a section of the brake mechanism shown in released position to permit a train to pass; and e Fig. 4 is a diagrammatic view illustrating the control means for the back, middle, and front brakes of the system.

Amusement park rides of the so-called roller coaster type usually consist of a trackway containing sharp curves and steep inclines. Trains consisting'of from one to several cars are pulled to the top of the trackway structure, usually by a chain mechanism, and then released to travel brake system in which the brakes'are normally train from the time it leaves the loading platform .Where he has an uninterrupted view thereof and over the remainder of the trackway as a free roller coaster.

' Located at or nearthe bottom of the chain is a loading platform from which passengers enter the various cars of the train, and adjacent to this loading. platform is an unloading platform upon which riders who have finished the ride disembark from the train. In most instances the roller coaster trackway is long and two or more trains are operated on it simultaneously. j Various arrangements are provided to insure proper spacing of the trains on the trackway, as for example, the interlocking control device shown in the Patent #2,310,039, issued February 2, 1943. Such devices control the until it enters theapproach to the unloading platform.

Prior art rides of which I am aware have usually had what is known as a back brake located in the approach to the unloading platform. ,Frequently the back brake has consisted of a set brake and a controlled brake, the train speed being checked somewhat by the set brake and then further reduced by the controlled brake which has been adjusted by the platform attendant; An intermediate brake has been located in the unloading zone and manually operated by the platform attendant to control the movement of trains through that zone and onto a front brake located in the loading zone. The front brake has also been manually controlled.

These prior art systems are perfectly safe when properly operated, but since they are manually controlled throughout by the platform attendant, any failure to act or any tardiness in acting on the part of the attendant may result in an unsafe condition. The present invention eliminates this hazard, as will presently appear.

In accordance with the teachings of the present invention, the back brake;intermediate brake, and front brake are all normally set 'to stop a train. Controls for these brake mechanisms are taken off of the platforms andextended to a control booth, preferably located above and near the outgoing end of the platform, where an operator in the booth will have a clear view of'both platforms and'the'approach to the unloadin platform. Since the operator is thus removed from the platform and its distractions, he will be less likely to have his attention distracted from the work at hand. Located in the control booth are simple controllers which must be operated by the operator to release the brakes s0 as to permit passage of a train over the brake. If the operator the trackway is positive and the likelihood of an fully explained in said patent.

oncoming train ramming into a standing train is eliminated. Should the single operator who controlling the entire ride permit his attention to be distracted, a train approaching, the unloading zone will be stopped on the normally set back brake, and a succeeding train will be stopped by the interlocking block system of the prior patent before it can move into an unsafe position.

Brake systems employed, to stop roller coaster trains usually 'consistoftrack'wa'y brake shoes mounted between the railsand adapted to be elevated so thatthey 'will'be engaged by brake shoes on the train to bring the train to rest. In certain instances the brake'shoe'sare moved laterally to engage vertically disposed brake shoes on the train, thereby to bring the train to rest. In either case, notwithstanding counterbalances, considerable force is required to move the brake mechanism into set position in which it will engage and stop a train. Mechanical means for so setting a brake can be extended to the central control point; however, a, much more rapid control of the brake can be accomplished through the use of fluid pressure, either pneumatic or hydraulic, located at the brake, itself. All the pressure lines'in'la fluid p'ressuresystern should be maintained asshort as"possible to minimize the chances for leakage; and toper- 'mit speedy operations with a minimum volume of fluid, and tothis end valves "for controlling the fluid pressure brake'operating devicesj'are located near the brakes and" preferably are elecjtromagnetically controlled so thatit is, only nec} essary to extend to the central control booth suitable electrical connections to these electro-'- magnetic valves. The controllers in the booth are electric switche'scapableof bein quickly manipulated and capable of'being manipulated. in only one 'way; "While electromagnetic valves are preferred and are readily available on the open market, other remotely controlled valves actuated by fluid pressure ormechanically may be substituted ifdesi'red. Also located in the control booth and 'injuxtaposition to the controllers are suitable signal lights or other indicators through which the operator. is given an indication of the position of each brake on the ride, and such other data as needed for the safe control thereof. 7

' Referring now to the drawings in more detail, in Fig. 1 there is shown the platform section of a roller coaster, from which section the trackway I leads to the right and. onto the chain (not shown) by which trains are elevated to the high pointof the ride and run free to the approach 2. leading to the platform section. The platforms are two in numberpplatforrn 3 being an unloading platform. onto. which riders disembark. at the end of their ride, and platform 4 being a loading platform from "which rid ers enter the trains. In the approach section 2 of, the trackway isa brake hereinafter, err rlt as the ask r ke which is long enough to stop any train on the brake and before the train reaches the unloading platform. This brake 5 is normally set to stop a train and is located at the outgoing end of the last block in the interlocking system of Patent #2,310,039 when the trackway is equipped with such a system. In the event that a train is stopped on the brake 5, as may happen in the case of an. unusualoperation a. succeeding train on t'he" ltrackway, wijll stripped at the entrance to this last block in the manner more Normally, however, the operator will release brake 5 on the approachof a train,-as will presently appear.

Located at the unloading section 3 of the platform is an intermediate brake 6, likewise normally set to stop a train. While somewhat shorter than the back brake 5, brake 6 is nevertheless long enough to stop a fully loaded train when that train is traveling at its normal speed of approach to the unloadingplatform. Located adjacent the loadingplatform 4 is affront brake"T'which is shorter than'bra-ke and is used to control trains "atthe loading platform,

erator is removed from'thel latfolirn and'its dis- I tractions' are therefore removed from him, so that lie is. moreaptto give his undivided atten tion, to his work. Located in. fr'ontpf the operator is the control panelj'shown in Fig. 2, the details of which will. be hereinafter explained. 'The particular constructionlof the brakes will, of course, vary with theindividual rides to which the system of the present 'invention is applied, and in Fig. 3 a, typicatbrake is shown by way of example. This brake. consists of a shoe 48 supported, by av plurality offsets of levers H and [2 that are pivoted together'a't I3 and connect: ed, through this pivot to. athrustrod '14. The levers l2 are pivotally'connected to'asupporting base member l5, as, shown. I

Also connected to the brake is a suitable counterbalance mechanism which, in the example shown, consists o'f'a rod [6 pivoted to the brake, and also. tofav pivoted, lever I 1 mounted upon the base. l5,v which lever l1 carries. a, counterweight 18 that is sufficiently, heavy "to be effective through the lever systern lto counterbalance. completely the weight of the'brak' and. its 'mounting levers. 'If desired, the counterweight may slightly onerbalance the brake.v

Connected to. the thrustlrod mere brake actuators 20 and 2!, actuator, 20, when energized, moving the, thrust rodlt toilie right. Fig. 3, to elevate the brake lllinto position to stop a train, and actuator 2|, when energized, moving thethrustrod l tto the leftinto the position in which itis shown insolid lines in Fig. 3 to release the/brake. AotuatorsZll and 21. may be any, suitable .fluid pressure. responsive devices, a um er of hich ar reedily ava ble p h 91 2 m r et: e e ably. howev t es d vices are diaphragm type, pneumatic actuators 51? such as i are commonly employed to actuate brakes on. trucks andstrailers, this-particular type of actuator having been foundto. be. very economical in its use of fluid pressure, very rapid in its operation, and easy to maintain inproper working condition.

It will be noted that when the actuator. is energized and thrust rod- |4v moved to theright, Fig. 3, .the pivots l3 between the links H and I2 move slightly past center, that is, past a line drawn between the center; of the pivot by which the link H is connected to the brake l0 and the center of the pivot bywhich the link I2 isconnected to the base l5. In a braking system wherein links H and I2, when aligned as shown in dotted lines. in Fig. 3, elevate brakeshoe .lfl, engagement of that shoe l5 by ,the-brakeshoes on the cars of the train mayiactually raisethe train so, that it is supported by the brakeshoes rather than by the wheels.v Such an arrangementis, common in the art, and Fig. 3, being an elevational view, shows a brake ofthis .typeand the main weight of the train on the brake is carried by the, links H and l2, the actuator 2|] merely holding the links in alignment.

Also connected to one of the links H byv a suitable arm 22 is a mechanical reset weight 23 which is sufficiently heavy to move the brake from a released to a set position, so that in the event of a, complete pressure failure, with the brake in released position, themechanical reset will move the brake to its set position.

The brake it], its counterbalance and supporting levers shown in Fig. 3, is in reality merely a section of a brake; and a long brake, such as a the back brake 5, will consist of as many sec- The control valv es'2i and 28 are'preferably electromagnetically operated fluid pressure control valves, several types of which are readily available upon theopen market. In the case of the valve 21 which. controls the actuator 20 to move the brake to set position, when the electromagnet 29 of thhis valve is deenergized, fluid pressure will be admitted from the pipe through the valve 21 into the chamber of the actuator 20 where it will bear against the diaphragm therein to move the thrust rod M to the right. When the magnet 28 is energized, the valve will be moved to block supply pipe and to connect the chamber in the actuator to an exhaust port 30, thereby permitting the pressure in the chamber to escape.

Control valve 28 is arranged in a reverse position, that is, whenthe electromagnet 3| is ,deenergized, the fluid pressure supply pipe 25 is blocked and the chamber of the actuator 2| is connected to an exhaust port 32 so as to prevent pressure inthe actuator 2| from opposing the movement of thrust rod Hi to the right, as seen in Fig. 3. When magnet 3| is energized, the valve moves to block the exhaust port 32 and to connect the fluid pressure supply pipe 25 to mightinteriere with. the proper operation of the actuators. InFig. 4, the actuators 20 and 2| associated with the backbrake 5 are shown at the left of the figure and designated as 520 and 52| respectively, the actuators associated with the. intermediate brake 5 are shown in the center of the figure as 620, and 82l respectively, and the actuators associated with the front brake 1 are shownat the right of the figure as 120 and "I respectively. It will be noted that each of these pairs of actuators is equipped with its own individual fluid pressure reservoir 524, 624 and 124 respectively, and that these reservoirs are ,con-. nected by suitable, piping 35 through ,a suitable filter 35 to a main fluid supply reservoir 31 that is located adjacent to the pump, not shown, by which this fluid pressure is generated. Each of the reservoirs 24 isequipped with an individual check valve 38 for 52 35 for 524, and 40 for 724, so that in the event of a leak or rupture of the: main supply pipe 35 pressurestored in the reservoirs will not be lost. Each of the reservoirs contains a sufficient quantity of fluid to operate the associated brake a sufiicient number of times to clear the ride.

Electrical current for operating the system may be commercial alternating current of approximately 110 volts potential and is led into the system through conductors 4| and 42. Conductor 48 is extended through normally closed contacts &3 to conductor 44.that leads to one terminal of the electromagnet 529 of the valve 52? associated with the actuator 520. A branch of the conductor 44 extends to one terminal of the electromagnet 53| of the valve 528 associated with the actuator 52L- The other terminals of the electromagnets 529 and 53| are connected together by a conductor 46 that extends to a normally open switch 41, the other side of which is connected to conductor 42, As will be seen in Fig. 2, switch 41 is located on the control panel 55 that is disposed in thecontrol tower 9 in front of the operator of the ride. Also located on this panel and associated with the switch 4! is an indicator or signal 48 which may be a lamp. As will be seen in Fig. 3, when the brake shoe i5 is in its relased position, it engages a lever 5| by which contacts 52 are closed to connect a signal lamp, such as 48, across a source of current, thereby to cause the lamp to burn and indicate to the operator that the brake is released.

Conductor 44 is extended through conductor 54 to one terminal of the electromagnet 529 of the valve 621 associated with the actuator 620,, and also through conductor 55 to one terminal of the electromagnet 83| of the valve 628 associated with the actuator 52L the opposite terminals of these magnets 529 and 63! being connected together by a suitable conductor 55 that is con nected to normally open switch 51 that is also connected to the conductor 42.. Switch 5'! is 10- cated on the control panel adjacent the inter,- mediate brake indicator thereon, which intermediate brake is provided with a signal lamp 58 adapted to be lighted by the switch 52 of the intermediate brake, as hereinbefore explained.

- The normally closed switch 43' by which conductor 44 is, connected to one side 4| of the source of electrical current is controlled by the transfer table 8, Fig. l, and its contacts remain closed so long as the table is in position to extendthe trackway from intermediate brake 6 to front br ke} A sponas metransi r ableismovedyt 7.' the contacts of switch 43 are opened to prevent the operator from releasing either the back or the intermediate brake while the trackway is interrupted. I

Conductor 4| is connected through conductor 64 to one side of the electromagnet 129 of the valve 12! associated with the actuator 120 of the front brake T, and also through conductor 65 to one terminal of the electromagnet 731 of the valve 128 associated with actuator 12], the other terminals of these magnets 129 and 731 being connected together by conductor 66 which extends through normally open switch 67 and conductor 69 to normally open switch contacts located in the interlocking system of Patent #2,3l0,039, and thence through conductor H to the other side 42 of the source ofelectrical current. Switch 61 is located on the control panel 50 adjacent the indicator of the front brake thereon, and a signal lamp-68 is associated with this switch. An auxiliary switch 72, which is normally open, may be provided and connected between conductors 66 and H to by-pass the interlocking system. This switch 12 will not be located on the control panel 50, but will be located in the control booth 9 in a relatively inaccessible spot therein, so that it is not likely to be inadvertently operated by the operator. This switch, serving as an auxiliary front brake release, will be used only when it is desired to release the brake before a previous train has cleared the block, as might be the case when placing an additional train on the ride.

Back brake 5 may consist of a lurality of sections, each of which is equipped with actuators 520 and 52!, or a single set of actuators may be used to operate the several sections. In the event more than one pair of actuators is employed, conductors 44, 45 and 38 will be extended to corresponding magnets of the other pair of actuators, as indicated by the arrows 13. Similarly, conductors 54, 55 and 5% may be extended to other actuators on the intermediate brake B, as indicated by the arrow 15, and conductors 64, 65 and 66 may be extended to other actuators on the front brake i, as indicated by the arrow 16.

Control panel 50 may be provided with a pressure gauge ll, preferably either an electromagnetically operated gauge or a closed column fluid pressure gauge, in either case actuated by a suitable actuator 18 that is connected in the main fluid pressure supply pipe 35. This particular type of gauge is used to avoid the necessity of running a branch of supply pipe 35 to the control booth. Associated with the gauge i1 may be a signal light I9 which will be lighted by suitable means not shown, when the pressure falls below a predetermined minimum. If desired, an audible signal may be added to be sounded when the pressure falls to a certain value. The control panel 50 may also contain a signal lamp 80 that is lighted when the transfer table is moved to disrupt the trackway between brakes 6 and l, and if desired signal lamps 8| and 82 may also be provided and connected to be lighted when trackway brakes of the interlocking system are operated to stop a train on the structure.

In most rides of this kind, the trains are elevated to a topmost portion of the structure by a chain which is driven by a suitable source of power, usually an electric motor. Control panel 50 is preferably equipped with a switch i23that may be pressed by the operator to actuate the usual electromagnetic devices in the motor control to stop the chain should occasion arise; and associated with this switch 83 isasignal light 84 which may be connected to burn when the chain motor is running in a normal manner, or may be connected to burn when the motor stops, as desired.

To prepare the system for operation, the come pressor, not shown, is started to pump up normal operating pressure in the main supply tank 37, fluid flowing from that tank through the supply pipe 35 to the reservoirs 524, 624 and 724 associated with the three brakes. Preferably in the pneumatically operated system shown, this normal operating pressure is about pounds per square inch, notwithstanding that the actuators 20 and 2| will operate the mechanism in a satisfactory manner on a much lower pressure, in fact, as low as .30 pounds to the square inch. The higher normal pressure provides a margin of safety which is desirable and also makes the brake operation more rapid and supplies sufficient power to set the brake when there is a train on it. Electrical power is next applied to the system and the motor that drives the chain of the ride is put into operation in readiness for the passage of trains over the trackway.

Assume first that there are no trains on the trackway, but rather that all of the trains are stored on the storage track. The transfer table will be moved and one of the trains placed upon it preparatory to placing that train on the trackway. As soon as the transfer table 8 moves out of its home position, contacts 43 will be opened without particular effect at this time. The table is then moved back to bring the track upon which the train is resting in alignment with the track way and the train then pushed onto the front brake 1 in readiness to receive passengers.

As soon as the train is loaded, the operator closes switch 61. Since there are no other trains on the trackway, the block will clear and contacts 10 in the interlocking system of the above mentioned patent will be closed and the previously traced circuits for magnets I29 and 13! will be closed and those magnets energized, magnet 729 moving valve 121 to release pressure from the actuator 12!! and permit that pressure to escape through the exhaust port 30. Magnet 13! operates valve 728 to connect actuator Hi to the source of pressure in reservoir 124, operating that actuator to move the brake to released position, whereupon the train moves off of the brake to start its run over the trackway.

As soon as the operator sees the train on the trackway section 2, approaching the back brake 5, he operates control switch 41, thereby closing the circuits of magnets 529 and 59H to cause actuators 520 and SH to move the back brake 5 from its set to its released position, and the train travels over the brake without any reduction in speed and onto the intermediate brake 6 which is in set position. The intermediate brake brings the train to rest at the unloading platform.

If the operator should observe that the train approaching the unloading platform is traveling at an excessive speed and that there is a likelihood that the shorter intermediate brake 6 will not stop the train at the unloading platform, he removes his hand from switch 41, which restores to normal, thereby de-energizing magnets 529 and 53I which operate their associated valves to re-set the brake. The train will be slowed down by the back brake and when it has reached a safe speed, the operator again closes switch 41 to release the brake and permit the train to proceed to the intermediate brake.

' As soon as the train has cleared brake 5, the

.operator removes his hand from the-switch 41 maining on the train for another ride, the 'op-' erator closes switch 51, thereby energizing magnets 629 and 63l which control their respective valves to release the intermediate brake 6 and permit the train to run forward onto the-front brake. As soon as the train has cleared the intermediate brake, switch 51 is released and the intermediate brake re-set to stop a succeeding train, thereby-completingthe cycle of operation.

In the event that the volume of businesspecessitates another train to be put on the trackway, as soon as -the first train moves onto the frontbrake '1 the transfer table can be operated to align 'it with the storage track preparatory to picking up another train. Since the electrical circuits to front brake l are not interrupted by contacts 43, the first train may be released from the" front brake as soon as it has been loaded; and shouldanything happen delaying the movingof'the second train onto the trackway,- so much that the first train reaches the back brake before the second train is in place, the first train will be stopped on the back brake 5, and since the control circuits to that brake are opened by contacts 43 there is no possibility of the operator releasing that brake, even though he might get excited and try to do so.

In the normal operation of the ride, three or more trains may be used, provided, of course, the trackway of the ride is of normal length. One of these trains will be on the trackway near the beginning thereof, one at the loading platform,

and one on the trackway at or near the approach to the back brake, this spacing being maintained by the interlocking mechanism of the aforementioned patent.

Preferably under these conditions, the train at the loading platform will be loaded and will move off of the front brake 1 before the succeeding train reaches the back brake 5 so that at any one instant the operator need concern himself with but one train.

In the event that after the operator has closed switch 4'! to release the back brake his attention is distracted and he releases switch 41, or if the source of electrical power should fail at the instant, the magnets 529 and 53! by which the back brake is controlled will be de-energized and the brake will move to its set position. If, at

the instant that the power fails, the main fluid pressure supply line 35 should likewise break, the back brake would nevertheless be set, since there is a sufficient quantity of fluid in the reser- {voir 524 to operate the brake several times. Should the supply pipe 525 between the reservoir 524 and actuators 528 and 52! break, or one of the actuators suddenly become inoperative, the back brake 5 will be set by its mechanical reset weight 23; and while this weight may not be capable of completely setting the brake, if the train is already on the brake, it will nevertheless supply suflicient braking pressure to the train to slow it down so that it will approach the intermediate brake at a safe speed.

Throughout the foregoing, the braking system of the present invention has been described as being manually controlled. There are many d- 53120 vantages to such control; however, in certain instances full automatic control may be advantageous. The control buttons may then be replaced by contacts on a program clock which will then operate the brakes in timed sequence to render the control of the ride fully automatic.

All of the parts'employed in the braking systern of the present invention are standard parts readily available on the open market, so that in the event of failure of one of those parts it can be quickly replaced without waiting for specially made repairs.

While I have chosen to illustrate my invention by showing and describing a preferred embodi merit of it, I have done so by way of example only, as there are many modifications and adaptations which can be made by one skilled in the art within the teachings of the invention.

Having thus complied with the statutes shown and described, m inveits'tion, what I consider new and desire to have protected by Letters Patent, is pointed out in the appended claims.

What is claimed is: r

1. In a service braking system for an amusement park ride having a trackway: a balanced brake on said trackway; toggle links supporting said brake and arranged when aligned to move the brake to set position to 'stop atrain means including a fluid pressure actuator for moving said brake to set position; means including a second fluid pressure actuator for moving said brake to 2. released position in which a train may pass over the brake; a source of fluid pressure in juxtaposition to said actuators; an electromagnetic valve for each actuator, the valve for the first actuator being arranged to admit fluid pressure from said source to said first actuator when the electromagnet is de-energized and the valve for the second actuator being arranged to admit the pressure from said source to the second, actuator when the electromagnet is energized, an electrical circuit for said electromagnets, and a normally open manually operable non-locking single throw switch for closing said circuit to simultaneously energize both electromagnets thereby to remove presssure from the first and to apply pressure to the second actuator to move the brake from a set to a released position and to maintain the brake in a released position so long as said circuit remains closed.

2. The combination with an amusement park ride having a trackway and a balanced brake on said trackway adjacent an unloading platform; of fluid pressure actuated means for setting the brake to stop a train; fluid pressure means for releasing the brake to permit a train to move along the trackway; a source of fluid pressure; a valve for controlling the admission of pressure from said source to said brake-setting means; a magnet for operating said valve, said valve admitting pressure to the setting means when said magnet is de-energized; a second valve for controlling the admission of pressure from said source to said brake-releasing means; a second magnet for operating said second valve, said second valve admitting pressure to said releasing means when said second magnet is energized; an electrical circuit over which said magnets are operated; and manual switch means for closing said circuit thereby to operate said magnets simultaneously to release the brake and permit passage of a train along the trackway.

3. The combination with an amusement park ride having a trackway and a balanced brake on said trackway adjacent an unloading platform,

in u

an electromagnetic control valve for each fluid pressure means, the first valve connecting said setting means to said source of pressure when the magnet is de-energized and the second valve con necting said brake-releasing means to said source of pressure when the magnet is energized; and means including a manually operated switch for controlling an electrical circuit over which said magnets are energized in parallel thereby to move the brake from set to released position and permit atrain to pass over the brake.

4. The'combination with an amusement park ride-having a trackway, a balanced brake on said trackway adjacent an unloading platform and a control tower remote from said platform from which the trackway and brake are visible, of a fluid pressure activator for setting the brake to stop a train; a source of fluid pressure; piping connecting said activator to said source; a valve in said piping normally set to admit pressure to the activator; an electromagnet for operating said valve to shut on the flow of pressure to the activator and to permit escape of pressure in the activator; a second activator for moving said brake to a released position to permit movement of a train along said trackway; piping connecting said activator to said source; a second valve in said piping normally set to prevent pressure from said source from entering said second activator and to vent said activator; a second electromagnet for operating said second valve to close the vent and to admit pressure from said source to said second activator; an electrical circuit for said magnets extending to said control tower, and a manual switch in said tower for closing said circuit thereby to operate said magnets simultaneously to release the brake and permit passage of a trainalong the trackway.

WILLIAM B. SCHMIDT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 952,494 Atwood Mar. 22, 1910 1,012,059 IBurchard et al. Dec. 19, 1911 1,576,623 Barr Mar. 16, 1926 1,638,630 Hannauer et a1 Aug. 9, 1927 1,898,802 Wood et a1 Feb. 21, 1933 2,422,416 Humphrey June 17, 1947

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