US1192086A - Automatic train-stopping device. - Google Patents

Description

J. MARCROFT.

AUTOMATIC TRAIN STOPPING DEVICE. APIPLICATION FILED MAY 5. 1913 1 1 92,086. Patented July 25, 1916.

4 SHEETS-SHEET I.

MIIIIIIIIIIIIII WITNESSES F INVENTO J. MARCROFT.

AUTOMATIC TRAIN STOPPING DEVICE.

- Patented July 25, 191B.

4 SHEETS-SHEET 2.

APPLICA'HON' FILED MAY 5, 19I3' WITNESSES |N\/E mo L-MARCROFT.

AUTOMATIC TRAIN STOPPING DEVICE.

Patented July 25, 1916 4 SHEETS-SHEET 3.

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:m mm o. c.

1. MARCROFT. AUTOMATIC TRAIN STOPPING DEVICE.

APPLICATION FILED MAY5 I913 Patented J uly 25, 1916.

4 SHEETS-SHEET 4 WITNESSES .pelled-enginesn a.

z saws JESSE MARGROFT, 0F PROVIDENCE, RHODE ISLAND.

AUTOMATIC TRAIN-STOPPING DEVICE.

Application filed May 5, 1913. Serial No. 765,638

State of Rhode Island, have invented. certain new and useful Improvements in Autoinatic 'lrain-Stopping Devices, of which the following is a specification. E

My invention relates to safety stoppingdevices for railroad trains and consists pf an improved mechanism for automatically shutting off the power and applying the, brakes when a danger signal is set against the train.

The object of my improvement is to provide a device which will be absolutely positive in action, thoroughly reliable under all conditions and completely independent or the manual means of control for the engine, so as to be entirely beyond the control of the engineer.

The invention is fully described in the following specification, illustrated by the accompanying drawings, in which like letters of reference designate like parts.

In the drawings: Figure 1 illustrates a usual type of steam locomotive with my new stopping-device applied thereto; Fig. 2 is an enlarged, sectional view of the principal elements of the device ;Fig; 3 is a rearend view of the locomotive shown in relation to the rails and signal-mast to illustrate the electrical connection tl'icrebetween; Fig.4 is an enlarged, detail view of the automatic electric-switch on the signal-mast; Fig. 5 is a view showing the electrical connections between the locomotive and the cars of the train; Fig. 6 is a diagram of onesystem of electrical WlPlIlg which may be employed do control the device. it i I have referred to herein.

- Referring first itoLFig. :1, I A; aiep lustrat'e and" describe my inventioni applied to steamlocomotive and arrangeclzegtoflbe operated through steam pressure, butirit 1 is/to he Jun-"I; derstoodthati the samednechanism might be operated by any fluich 1f1ressinie, suchl as air, and theref re ii lie device is adapted rot-r use" on electric locomotivesiorf oniothen'se ff rsentswa well known-1 type of steam ilocomotiivei 01":611-i3 gine having the ,usiral longitudinal boiler with the @engineers cab oat thenreai' ends 0111 the top of tlieboiler B Tis'the.steam tdomey D from which the steam leads to the driving I p cylinders 0 through the main supply-pipeEf see also Fig. 2. The steam is admittedto the pipe E through two opposite ports 0, a, normally closed by a double throttle-val .'e F

of the puppet type. Th throttle-valve F is H k 'cranklever 7. which is controlled by a rod operated by arstem-f connected to a :bell- Specification of Letters Patent. Pa tnted July 25 1916; V

or link 7. Thelink f runs longitudinally of the boiler and is connected with the engiers throttle-lever located in the cab of the l engine, but not here shown.

The above designated elements are all common to the usual'type of steam locomotive and my new mechanism is arranged in relation thereto as now described.

Between the throttle-valve F and the cylinders I'place anauxiliary shut-otf valve 9- in the pipe E adapted to entirely close said pipe to prevent the steam from reaching the cylinders to operate the engine notwithstanding the throttle may be open. The

valve G may be of any suitable form, but as hererepresented is of the butterfly type having'a pivoted plate 9 arranged to swing across the opening of the pipe E when operated by the crank arm g.

Tapped into'the end of the main steampipe E, is a relatively small pipe H which leads through a stufling-box h in the side of the steam-dome D and is connected to a. small cylinder or steam-chest J. The cylinder J serves as a valve-chamber and forms part of or is attached to a larger cylinder K, the two being connected at their lower ends by a pipe 2' or any suitable arrangement of steam duct. Adapted to slide in the valve chamber J is balance-valve ordouble pitston Jzuhaving.twoheads j, j arranged at a-w distance apart and' normally positioned equidistant from the opening of the =le'ad'-w- 59.5 valve-chamber J- are arranged 1 to register with the piston heads j; j to be closed thereby:

pipe HM Twoports 7' 7' in the side of the when the piston J is" in its lowermost posi tionu T-he wports j fi fare' connected duct 7'? which renders them-intercommunicatingz" The/rod 3' of the piston J extends i through a stalling-box j. and is. connected at its'endawith a linker connecting+rodl The opposite end ofthe link [is connected to one i end: of a lever or rocker-arm Ir pivoted at Z one'any insuitablewfixed support, not heron. :1.

shown. Connected to the opposite end of the rocker-arm L is a link Z having its lower end attached to a hinged arm M which serves as an armature for the electro-magnet M. A suitable coiled spring 0 attached to the arm L serves to normally maintain the armature M in a raisediposition away from the ends of the magnet M. The magnet M as here shown is of a well known type having two coils m, 'm and the usual axial cores m, m. In place of this arrangement however, the common form of solenoids might be employed with their armatures atta ched to the link Z and arranged to slide in the coils. One lead fromthe magnet M is connected to a battery N by the wire n and the opposite lead grounded in the frame of the locomotive at a.

The 1 cylinder; K is designed: to serve as the main sourceof power for'actuatingthe mechanisnrwhich shuts off the powerofithe engine and operates the brakes of the train.

7 Arranged to slide'in the cylinder K iS'a piston K having its rod 76 extendingthrough a stuffing-box 7c and pivotally attached to the connecting-rod 72.5, The rod 79 has its op posite end connected to one arm of a bellcrank-lever P which is pivoted at p to any suitable bracket or standard(not here shown, attached to the-frame of the engine. The

opposite arm of the lever Pis connected to a link or rod P which extends to the arm g to adapt it to operate the valve Gin the main steam-pipe E.

A spring 72 serves to normally maintain the lever P in the position illustrated in Fig. 2 with the piston K adjacent the bottom ofthe cylinder K;

The air-brakes of thetrain are usually controlled through the relief of air-pressure which'no'rmally acts to 7 hold the brake mechanism inoperat ve. For this purpose theengme carries-an air tank I sometimes arranged at the side of the cab C as illus-. trated in Fig. 3, and connected with a pipeline leading through the cab 1 and-thence to the several coaches of the train; The engineers brake-operat ng valve 1s located on this line, within convenient reach in the cab,

arranged to operate arelief-valve R located at the end of a pipe 7 leading from'the plpe g. 7 Referring to the enlarged view of the mechanism, Fig. 2', the valve R may be of anysuitable type and as here shown is operated by'a lever 1 connected by a rodor link '1, leading to the bell-crankJeVer P.

For'the sake of clearness'I have shown the elements of thedevice above described as exposed to view on theoutside of .the locomotive. It is to be understood, however,

Referring to Figs. 1 and 3, one pole of the battery N is connected by a wire s to a contact-shoe S located at any convenient point 'on the engine frame. For convenience of illustration I have shown the shoe S at the rear of the driving wheels, but the preferable arrangement would be to place it either under the pilot or between'the wheels. In

either ofithesepositions it will then be out p of the way and beyond reachfrom the outside so as to prevent disconnection of the wiring or interference with its operation. The shoe S may be of any suitable form.ar-

ranged to be pressed against a contact-rail 1 running parallel with the main rails T,

T .v As here illustrated the shoe S is pressed into contact with the rail T by a' coiled spring 5 on the rod 8 and these parts are insulated from the iron-work of the engine by suitable means, such as the wooden blocks. Any other arrangement of'contact-shoe' and rail could be used in place of that here shown; for. instance the usual third-rail system of electric roads might'be employed. The contact-rails Tare placed alongside the main rails, either inside or outside thereof,

at points adjacent the signal-masts of'the block-signal system now generally used on railroads. In Fig. 3 I have shown a usual form of signal-mast U having a pivoted semaphore-arm .U at the top arranged to be actuated through the vertical roda. The

rod u is operated throughthe usual mechanism, not here shown, which is'controlled from the signal tower or despatching station by either mechanicalbr electrical meansL Mounted on or formed as a part of the mast U, I provide a switch-box o inwhich is incased the circuit-closing switch V for the electrical controlling-meansfor the stoppingdevice. The switch V may be of any suit able form, but as here shown is of the knife type having a blade 4) pivoted at one end on a binding-post v The outer end of the blade 4) is connected to the rod to,

preferably through a pin-and-slot arrange ment shown at c A second binding-post v is provided with the usual spring-contacts adaptedito impinge upon the blade c. From the binding-post o a wire tleads to one of the main rails T, being electrically connected therewith; and a second wire 6 leads from the post 12 and is electrically connected with the c0ntact-rail'T.. a

The above described mechanism with its electrical connectionsis sufficient in itself to accomplish the object of the present invention, that is, the automatic stopping of the train through the operation of the signal system, as hereinafter fully explained' To make the device more dependable and eflicient, however, and to provide for its manual control from the several cars or coaches of the train I provide the additional electrical connections shown in Fig. 5 and now de scribed: Connected with the wire 8 leading from the battery N is a wire to or other conductor arranged to extend the length of the train. That is to say, each car or coach will be wired on a lead w from the battery N to connect with every other car. This wiring can be carried in suitable conduits arranged to be coupled with the air-pipe couplings at the ends of thecars. On one of the trucks of each car I provide contact shoes Sf, S etc, see Fig. 6, havingelectrical connections w, 10 etc., leading from the wire w. These shoes may be similar in form to the shoe S carried by the locomotive and, like the latter, are insulated from all other parts of the cars. Their operation and purpose are also the same as that of the shoe S, that is, to close the electrical circuitto energize the magnet M, as more fully explained hereinafter. Through this arrangement I provide a plurality of contacts which insure a more reliable control of the device and guard against failure of operation should the contact shoe on the engine become broken or deranged. Another advantage in this extended system is that the contact-rails along the tracks can be made shorter, since a relatively long period of time will elapse during the passage of the whole train over a given length of rail, and hence there can be no danger of the train coasting beyond the signal and then being started again. Still another benefit arising from the continuous circuit throughout the train is that it allows for placing emergency-switches in the coaches, which take the place of the usual conductors valve for the air-brakes, and can be operated in case of accident or should other occasion require. Referring again to Figs. 5 and 6, I propose to install in each coach a hand-switch l/V arranged as follows: Any suitable manually-operable type of switch can be employed for this purpose and as here shown one of its contact-points w is connected bya wire w leading to the wire w; which connects with; the contact shoe S I throughthe wire 'wf, while theaothcr contact.

point'w has awire ,wc'wgrounded inthe' inetalrframe of'the truckjm of the coach 1A hand-lever 0 i of the knife-blade: type, or of. any-other suitable form, is arranged to I be. thrown to connect the two contacts; The

switch W ,is preferably inclosed -in'a suitable case W whlch may} be sealed with a glass ,door similar jgto those used: for fire-alarm boxes. In'this way the switch would be pro tected frommaliclous orj ignorant tampering, while at the same time being easy of access for those in authority. I i,

The operation of my complete device is as tem generally employed on railroads it'is I usual to control the blocks in pairs as follows: If one block is closed the next previous one will have its signal set at caution and. this distant signal, as it is called, warns the engineer to slow down his train so that he can come to a full stop before entering the next block should the home signal be set at danger. In some cases, however, only two positions of the semaphore are provided for, one indicating that the block is clear and the other that it is closed. My device can be applied to either system, but for the sake of simplicity I prefer to illustrate and describe its operation in connection with the one last described.

Referring to Fig. 3, the semaphore arm U is here shown in its raised position at danger, indicating that the block is closed. When the arm U is carried up into this po sition' through the operation of the rod u the movement of the latter actuates the switchblade 12 to carry it between the spring contacts on the bindingpost 0*, as shown by full lines in Fig. The closing of the switch V acts to connect the rails T and T through the wires If and t and in this way the contact-rail T is electrically connected with the rail T. Now as the train approaches the block if the engineer fails to observe the signal and does not stop the shoe S will come into contact with the rail T and complete the electrical circuit. The closing of the circuit operates the stoppingdevice in the following manner: The currentfrom the battery N passes from one pole thereof through the wire at to the magnet M and thence through the wire ml which is grounded in: the frame of the locomotive tob rin'gra'll of the metal parts thereof in circuit. Nowfsince the 'wheels of the 1000;;

motive-constitute a part of the circuit, the

current will pass therethrough to the rail" T and thence through the vvire[t ,"switch V and wire t; to thecontact 'aikT. From the above-it"will be seen that the opera tion of theswitch V as before described will close the circuit l'eading from' the batteryand includlng' the magnet M" and hence when this takes place the magnetcoils will lie tion of the valve J this pressure will be exerted equally against both heads 7', j, and

hence the valve will normally remain balanced-in the position illustrated in Fig. 2, V wlthout any tendency to move one way or the f other. When, however, the valve J 1s raised 7 bythe action of the magnet M theheads j, 7' will slide past the ports f, j to open the latter. The opening of the ports j j admits steam through the upper one and allows it to pass through the duct i and back into the cylinder J through the lower port sothat pressure is exerted against the lower end of the piston J to assist and accelerate the movementof the latter. At the same time, the movement of the piston or valve J admits the steam to the pipe 71 which leads to the cylinder K and consequently pressure is exerted again st the lower end of the piston K. This pressure forces the piston K upward in the cylinder K and through the connecting-rod 2) acts to rock the bell-crank-lever P against the action of its spring 32 The r rocking motion of the lever P actuates the rod P to turn the crank-arm g and close the auxiliary shut-off valve G. In this way the steam is entirely shut off from the driving-cylinders of the engine and hence the latter becomes inoperative or dead and 7 must stop.

To expedite the stopping of the train and prevent its coasting on a down-grade I have adapted my mechanism to effect the operation of the air-brake simultaneously with the shutting oif of the power of the locomotive. As here shown, this part of the device consists simply of the link or rod 7' con necting the lever P with the'relief-valve R and acting to open the latter when the steam-valve G is closed by theautomatic operation of the piston K. The relief of air-pressure in the pipe 7, which leads from the main pipe line of the brake-system, causes the operation of the brakes in the well known manner throughout the whole train. This brake-controlling mechanism is not absolutely necessary to the successful operation of my device and could be eliminated if desired. For instance, if the de-' vice were used only for slowing up trains at switches, crossovers, etc., it might not be required to apply the air-brakes and therefore only the steam-valve operating connections would be needed. At thev same time, the

device would be" more eflicient for all purposes if adopted'in its entirety andtherefore the complete arrangement is preferable. For instance, my new device is much more practical and elfective as an emergency-stop controlled from'thecoaches than the usual means of control through the conductors valve. With this latter device the power cannot be controlled from the coaches, but only the air-brakes. Therefore, ifemer= gency requires the stopping of the train by the conductor and his only meansis the airvalve, then the brakes will be set' while the;

power remains on and" consequently they will not have their maximumeliiciency. Besides this, when the'b'rakesiare' set against the power of the engine the shock and strain on the running gear are enormous and liable V to cause derailment and greatdamage. With my new device it is only necessary for the conductor or any other authorized'p'erson to throw one of the switches lV' located in the coaches and the electrical circuit will be completed to actuate the stopping-mechanism as previously described. In this way the power is cut from the engine and the brakes applied simultaneously so that the train will come to a stop in a very'short 7 time. This adaptation of the device is especially valuable as providing against'the locomotive running away or getting beyond control, due to incapacity ofthe engineer through accident, sickness or death.

After the train has been stopped through the operation of the signal-switch it is impossible to start it again until the signal isreturned to its clear position. The en gineer may manipulate his throttle as'much as he pleases, but as long as the armature M remains attracted by the magnet M steam will be admitted to the cylinder K to maintain the piston K" raised and thelaux- I iliary shut-oil valve G closed. Another advantageous feature of my deviceis that the engine will not start of itself even if the throttle is left open'when' the signal is returned to clear and the electric, circuit becomes interrupted or broken. When this takes place the magnet Mf w ll be deenerglzed, but its armature cannot be raised because the pressure of the steam admitted by are valvesand joints, will allow the piston K to be returned to itsnormal position, as illustrated in Fig. 2, under action of the spring 19 on the lever P. Now, when the magnet M is deenergized the armature M will be released to allow the return of the valve J under action of the spring 0, and hence when the throttle is opened again the ports j 7' will have been closed. This renders the piston K inoperative so that the valve G remains open and the engine can therefore be started again. To effect a quicker release of the pressure in the valvechamber J and cylinder K the engineer can open the air-cocks on the main cylinders through the operation of the lever usually provided. If desired a small relief-valve could be applied to the cylinder K and this might be arranged to be operated automatically.

One important advantage of my new device is that it can be applied to any type of steam locomotive now in use without material change in the mechanism of the latter. All that is required to put the device into practice is to mount its main operating parts on the engine in any convenient location and to connect it with the main steam-supply pipe for the cylinders. This connection simply necessitates an auxiliary shut-off valve in the steam-pipe E and a small pressure supplying pipe H leading therefrom.

As before stated, the same arrangement of mechanism can also be adapted to control the operation of electric locomotives by slightly modifying its connections. For instance, the pressure necessary for operating,

the piston K could be supplied by air taken from the main air-tank used for supplying the brake-mechanism as now generally ar ranged. The pipe H would then be connected to lead from the air-tank with a valve arranged to control the pressure. This valve would be operated automatically from the controller-devices for the motors so that when the locomotive was under power air would'be admitted to the valve-chamber J. Upon the closing of the circuit and energizing of the magnet M the valve J would be moved to admit air to the cylinder K. This air-pressure would then actuate the piston K to throw a cut-out switch and shut off the power from the motors. This cut-out switch would of course be independent of the manually-operated controller-dd vices of the locomotive, just as the shut-off valve G is independent of the main throttle F of the engine hereinbefore described, and all of such connections would be so simpic that illustration is hardly necessary; It will also be obvious that my improved device might be operated by air-pressure even when applied to a steam locomotive; That is to say, instead of leading the pipe H from the steam-pipe E, as first described, it might be led from the air-tank and with this arrangement there would be a valve in said pipe adapted to be opened automatically when the throttle is opened. It will be understood that any of these modifications might be made within the scope of the present invention.

While my device as above described is designed to be controlled by electrical means it might easily be adapted for operation through a mechanical trip-contact. Such an arrangement, however, would not be reliable, as it would be more liable to be rendered inoperative from outside influence, particularly in stormy weather, and could be tampered with more easily.

It will also be obvious that my new stop ping-device might be operated independently of the signal-mechanism. That is to say, the circuits could be closed by switches located at the signal-towers or despatching stations without dependence on the movement of the semaphore arms.

Various modifications might be made in the form and arrangement of my new device without departing from the spirit or scope of the invention.

Therefore, without limiting myself to the exact construction shown and described, what I claim is 1. In an automatic stopping-device for railroad trains, the combination with a locomotive having manually-operated powercontrolling means, of means outside the control of the operator for shutting off the power without operating the manual means, a fluid-controlled device for operating said shut-off means, means controlled, by the power-controlling means to maintain pressure in said fluid-device during the operation of the locomotive, and automaticallyactuated means controlled by danger conditions to release the pressure to operate the shut-off means.

2. In an automatic stopping-device for railroad trains, the combination with a locomotive having manually-operated powercontrolling means, of means outside the control of the operator for shutting off the power without operating said first-named means, a fluid-controlled device for operating said shut-ofi means, means operated by the power-controlling means to maintain pressure in said fluid-device when the power is on, and electrically-controlled means to release the pressure to operate the shut-off means.

3. In an automatic stopping-device for railroad trains, the combination with a locomotive having manually-operated powercontrolling means, of means outside the control of the operator for shutting off the power without operating said first-named means, a fluid-controlled device for operating said shut-oil" means, means connected with the power-controlling means to maintain pressure in said fluid-device during the operation of the locomotive, a signal-system, and means operated through said signal-system to release the pressure to operate the shut-off means.

4. In an automatic stopping-device for railroad trains,rthe combination with a locomotive having manually-operated powercontrolling means and power-actuated brakes, of means outside the control of the operator for shutting off the power and applying the brakes without operating the manual means, a fluid-controlled device for operating said shut-ofi means and brakeapplying devices, means operated by the power-controlling. means to maintain pressure in said fluid-device during the operation of the locomotive, and automaticallyoperated devices controlled by danger conditions to release the pressure to simultaneously shut oli the power and apply the brakes. l

5. In an automatic train-stopping device,

the combination with a locomotive having manually operated throttle valve for controlling the steam supplied to the cylinders, of an auxiliary shut-01f valve adapted to be operated without operating the throttlevalve, a fluid-pressure device for operating said shut-off valve, means controlled by the operation of the throttle-valve to maintain pressure in the fluid-device during the operation of the locomotive, and automatically-operated means controlled by danger conditions to release the pressure to cause the closing of the shut-off valve to effect the stopping of the train.

6. Inan automatic train-stopping device, the combination with a locomotive having a manually-operated throttle-valve, of an auxiliary shut-off valve adapted to shut oli the steam while the throttle-valve is open, a fluid-pressure device for operating the shutoff valve, means controlled by the operation of the throttle-valve to maintain pressure in said fluid-device when the throttle is open, and automatic devices controlled by danger conditions for releasing said pressure to operate the shut-0H valve to effect the stopping of the train.

7. In an automatic train-stopping device, the combination with a locomotive having a manually-operated throttle-valve for controlling the power thereof, an independent shut-off valve between the throttle-valve and the cylinders, a steam-pressure operated device for closing said shut-off valve, means to admit steam to said device through the throttle-valve, and automatically-operated devices controlled by danger conditions to release the steam-pressure to close the shutoff valve to stop the train.

8. In an automatic train-stopping device, the combination with a locomotive having a manually-operated throttle-valve for controlling the power thereof, a separate shutofl valve between the throttle-valve and the cylinders, a fluid-pressure device for closing said shut-off valve, a valve-chamber 1n said device, means controlled by the operation of the power without operating the manual.

means, a fluid-pressure device for operating said shut-ofimeans, a valve-chamber in said device, means operated by the power-controlling means to maintain pressure in said valve-chamber while the power is on, a valve normally maintained balanced against said pressure, and automatically-operated means controlled by danger conditions to move said valve to overcome its balance and release the pressure to operate the shut-off means. V7

10. The combination with a locomotive having manually-operated power-controlling means, of auxiliary means for shutting ofl the power without operating the manual means, a fluid-pressure cylinder, a piston in said cylinder connected to operate the shut- 0E means, a valve-chamber communicating with said cylinder, a double-headed piston valvein said chamber, means to maintain pressure in the valve-chamber during the operation of the locomotive to hold the valve normally balanced, and automatically-actuated devices controlled-by danger conditions to operate the valve to overcome the balance to admit pressure to the cylinder to operate the shut-off means.

11. The combination with a locomotive having manually-operated power-controlling means, of auxiliary means for shutting off the power without operating the manual means, a fluid-pressure cylinder, a piston in said cylinder connected to operate the shutofi means, a valve-chamber communicating with said cylinder, a double-headed valve in said chamber, means to maintain pressure in said valve-chamber, two intercommunicating ports in the chamber normally closed by said valve, and automatically-operated means controlled by danger conditions to move the valve to open the ports to admit pressure through one of them to pass through the other and enter the cylinder to operate the piston therein.

12. The combination with a locomotive having manually-operated power-controlling means, auxiliary means for shutting as the power without operating the manual means, a fluid-pressure cylinder, a piston in said cylinder connected to operate the shutoff means, a valve-chamber communicating with said cylinder, a double-headed piston valve in said chamber, intercommunicating ports in the chamber normally closed by said valve, means to admit pressure against both heads of the valve to maintainv the latter balanced, and means to move the valve to open the ports to admit pressure against the end of the valve to accelerate the movement of the latter and release the pressure to operate the shut-ofl?operating piston.

13. In a train-stopping device, the combination with a locomotive, of means to shut ofl" the power thereof, a piston for operating said means, a cylinder in which the piston slides, a valve-chamber communicating with said cylinder, two intercommunicating ports in said valve-chamber, a double-headed piston valve in said chamber arranged to normally close both ports, means to admit pressure to the valve-chamber to maintain the valve balanced, and means to move the valve to open the ports to admit pressure through one of them and allow it to pass through the other to enter the cylinder and operate the piston therein.

14. In a train-stopping device, the combination with a locomotive, of means to shut off the power thereof, a piston connected to operate said means, a cylinder in which the piston slides, a valve-chamber communicating with said cylinder, means to maintain pressure in said valve-chamber, two intercommunicating' ports in said valve-chamber, a valve adapted to normally close both of said ports, an electro-magnet, an armature connected to the valve, and means to energize the magnet to attract the armature and operate the valve to admit pressure to the cylinder for operating the piston therein.

15. In a train-stopping device, the combination with the main steam-pipe of the locomotive, of a shut-off valve therein, a lever for operating said valve, a piston for actuating the lever, a cylinder in which the piston slides, a valve-chamber communicating with said cylinder, 'a pipe leading from the main steam-pipe to the valve-chamber, two intercommunicating ports in the valvechamber, a double-headed piston valve adapted to be normally balanced by the steam-pressure to close both ports, and means to move the valve to admit steam through one of the ports and out through the other and thence into the cylinder to operate the piston therein.

In testimony whereof I affix my signature in presence of two witnesses.

JESSE MARCROFT. Witnesses:

WVILLIAM MARCROFT, HERBERT K. ALLARD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G.

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