DE2401623A1 - SAFETY DEVICE AGAINST COLLISION - Google Patents

Description

Safety device against collision

The present invention relates to a safety device against collision for vehicles traveling on their own route, this device having safety chains which are connected to a control center, further devices for determining the distance between two successive vehicles and for determining the distance between two consecutive vehicles and to determine the safety distance between two vehicles in order to trigger the braking of a vehicle or the interruption of the transmission line if the distance between two consecutive vehicles becomes less than the safety distance, or in the event of a fault in a safety circuit.

The previously known devices have a number of disadvantages, which are also caused by the complex, im The technical means used, as well as the faults in the security or the lack of adaptability are conditional.

The present invention is based on the object of eliminating these disadvantages by creating a safety device of the type mentioned at the outset, wherein

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the vehicles are without drivers, this means that the device according to the invention itself the risks can assess and react accordingly.

In general, the present invention proposes to create a device that has means for observation and includes for the decision, which have a secure way of working and in particular the principle of the movable and applying variable approximation sections.

For this purpose, the present invention relates to a device of the type mentioned at the beginning, against collision, which is characterized in that it has a counting device by recognizing markings which are arranged along the route, furthermore a computing device for determining the distance of the vehicle from one predetermined starting point and a device for converting this distance into a corresponding period of time, with a time stamp consisting of a synchronization pulse that is received by all vehicles in order to generate a position pulse that is transmitted by all vehicles and received by all vehicles, that the determination of the distance between a vehicle and the immediately preceding vehicle is carried out by comparing the position pulses, and that the safety device of each

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Vehicle compares this relative distance with the braking distance of the vehicle in order to brake the vehicle triggered as soon as the relative distance is lower than the braking distance.

According to a further feature of the present invention the braking distance is determined from the true speed of the vehicle "determined by a speedometer is determined with a perforated disk, which supplies its output signal to a function generator, which is set in motion by the position impulse and which emits an output signal as soon as the function generator reaches the true speed and that the vehicle is braked when the signal of the function generator is not included in the period corresponding to the distance that this vehicle is traveling and separates the immediately preceding vehicle from each other.

According to a further feature of the present invention the generation of an alarm is caused by a position alarm that is triggered separately or in Connection with a failure of the detector for the markings, a failure of the counter for the markings or a disturbance in the transmission path, this alarm becomes the control center by sending it out of a vehicle identification pulse, and the control

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According to a further feature of the present invention, the functional reliability of the chains (position calculation, braking distance calculation) is determined by the position Guaranteed from errors, whereby the functions have been divided and through self-secured testing the coincidence of the output signals of the split functions is performed, the absence of the Coincidence indicates a malfunction or risk of collision and causes the braking.

It is particularly interesting that the division or duplication of functions by two does not chains that are symmetrical to one another are ensured.

Each vehicle includes two complete safety chains. The control center also includes two complete chains associated with the two chains of each vehicle. The one from the two chains generated signals are compared for their coincidence, what the reliability of the invention Device improved. In the case of the simultaneous presence of an alarm in each chain the safety device controls the immediate interruption of the line.

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According to a further feature of the present invention, the command for immediate braking is applied all over the place Line sent from the control center by means of a logic circuit connected to a transmitter, which transmits on a security frequency that is picked up by a receiver in the vehicle, each Interference in the reception of the vehicle's transmitter signal triggers immediate braking.

In this way, a positive safeguard has generally been created by using only elementary functions. It is the logical "AND" link and the Logical function of the coincidence, which is an "AND" operation in a sampling period. The coincidence function is used to check this at given moments and during a given period of time simultaneous presence of logical states of mind.

In the safety device according to the invention, the functions are arranged twice and divided by using different circles and the coincidence of the output signals is checked. This arrangement of modules is called ⁿ self-monitoring ^{H in the following.}

The main advantage of the present invention is the absence of permanently installed devices on the ground, along the route, with the exception of the mar-

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markings. This eliminates any maintenance of equipment on the routes and has an effect significant cost reduction.

Due to its extremely high performance, the device according to the invention allows the infrastructure to be used to the maximum. For comparison, the train sequence can be increased by 50 % compared to conventional devices which require a minimum time interval of 90 seconds between trains, while the device according to the invention allows this interval to be reduced to 60 seconds.

The device according to the invention is also characterized by * if characterized by their low manufacturing costs, as well as by their great reliability.

In addition, the device according to the invention comprises no electromechanical components. The device is of versatile use 'and can be connected to any transport system with its own route be measured.

In the following the present invention is ad of an embodiment of a safety device against collision for vehicles running on their own route using the attached drawings in individually explained. Show it:

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Fig. 1 is a block diagram of the inventions according to s Safety device,

Fig. 2 is a diagram showing the receiver output signal, of the position impulse and the gate impulse for distance evaluation in Dependence on time,

Fig. 3 is a diagram for the time-dependent representation of the synchronization pulse, the time to Measurement, the true speed (E), the braking distance (F), the maximum speed (Gr), the braking distance pulse (H) and the Gate impulse for distance evaluation (I),

4 shows an illustration of the signals received by the control center as a function of currently.

According to the present invention, the security device between each train and the next train (or between each individual vehicle) Maintain a distance that is equal to or greater than that in a transport system with its own route than the braking distance of the next train in order to avoid a collision between two trains or vehicles.

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In order to simplify the description, the term "vehicle" alone is used in the following.

In the part of the safety device according to the invention located on board each vehicle, to at all times it is assumed that the respective preceding vehicle is at zero speed.

When the distance that separates a vehicle from the vehicle in front is equal to the braking distance of the vehicle behind Vehicle (accurate to a distance threshold value), the following vehicle applies rapid braking the end.

This is how the safety device according to the invention against collision, which is composed, functions in general from an on-board unit (V), which is installed once on board each vehicle group or individually on board running vehicle, and from a control center (PCC), which centralizes all information, to redistribute them among the various vehicles in a line or network. The inventive The device has to measure the relative distance between two vehicles, the braking distance of one to calculate each vehicle and this braking distance with the relevant relative distance for the purpose of eventual

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Compare triggering the Sclmell "braking.

In the following description, the safety device according to the invention is shown in its simplest form "limited. That means * that a part of the On-Board Unit (V) (the safety chain l) and a Part of the control center (PCC) is described, the description of the details not referring to the redundant Parts of the circuit are expanded (safety chain 2) 1

In order to measure the relative distance, each vehicle is equipped with a counter 1, which allows it to determine the distance traveled from a fixed starting point by counting fixed markings, also called "Eontakte ¹ *" and which are at constant intervals on the Each vehicle sends its distance value to all other vehicles. The difference between the distance traveled by the preceding vehicle and the distance traveled by the vehicle in question gives it the relative distance to be measured, Das Vehicle device (V) recognizes the distance covered by the preceding vehicle by selecting the distance value that it has received and which is immediately above its distance value.

The markings arranged on the route

2 consist for example of plates of about 0.1 m

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They are made of a light alloy and are set up about every 20 m. These marks are recognized by the vehicles by means of detectors for the markings that are attached below the vehicles and consist of oscillators with coils whose degree of coupling can be seen in the presence of a metallic mass changed (principle of inductive proximity detectors).

The pulses delivered by the detector for the markings are counted by a binary counter 2,2 '. This counter is reset to zero as soon as the train rolls over the starting point of the distance measurement section (Terminals). The state of this counter measures the distance traveled by the train.

To transfer the state. This counter to the other vehicles is used in a safety-related transmission device, which consists of a transmission line laid along the route and of transmitting and receiving antennas that are attached to the vehicles and the control center (FCC). At regular intervals, for example every 2 seconds, the control center sends a synchronization signal on the transmission line, which consists of a synchronization pulse, for example with a duration of 33 ms . This synchronization pulse is received by all vehicles. As soon as a vehicle

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receives this synchronization pulse, it sends a pulse on the transmission line, for example from 4 ms duration, which is delayed with respect to the synchronization pulse by a period which is proportional the state of its distance counter. The largest of these delays is even lower than that Period of the synchronization impulse (2s) · All these response impulses from the vehicles are in the control center (PCC) and immediately sent back on the transmission line to the vehicles. The measurement the relative distance of a vehicle in relation to the previous vehicle is carried on board the former vehicle in the following way:

As soon as a vehicle has sent its reply pulse, it hears the reply on the transmission line other vehicles. The first response pulse received by this vehicle is that of the previous one Vehicle · The time that separates this response impulse from the i's own response impulse is the too measuring relative distance proportional. This relative distance is converted into the duration a square-wave voltage, whose transition to the logic voltage value "1" by its own, transmitted Response impulse is triggered, and its return to the logical voltage value "1" by its own, transmitted Response impulse is triggered, and their

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Return to the logic voltage ^{value M} O ^{H is} brought about by the first response pulse "received after this pulse. This square-wave voltage is referred to as the gate pulse for evaluating the (relative) distance.

Calculation of the braking distance.

The braking distance of a train whose speed is V is given by:

d = aV ² + bV + c.

This theoretical braking distance takes into account the uncertainties in the true value of the negative rapid braking acceleration, the response time of the brake and all sources of error in the device.

a, b and c are coefficients. The calculation of the braking distance is based on the real speed of the train or vehicle, this speed is measured by means of the speedometer 10.

This speedometer 10 consists of a perforated disc (not shown) which is fixed to a guide wheel connected is. There are no braking or grinding processes, so there is also no slip.

The perforated disc is a metal disc with teeth, which is evenly spaced around the circumference

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are arranged; these teeth are scanned by an inductive pick-up, "using the same principle as applied to the detector for the markings. The repetition frequency of the pulses at the output of this transducer is proportional to the speed of the vehicle.

Starting from the measurement of the speed, the braking distance is provided by a binary function generator 11 Memory calculated.

The device according to the invention causes the comparison the distances and the control of the braking as follows: The relative distance results in the form of Duration of a square wave voltage. A simple means of making the comparison is to also use the Express braking distance in the form of a square wave voltage. To do this, 'create one opposite the own response pulse delayed pulse 12, which is synchronized with the rising edge of the gate pulse 6 for distance evaluation and has a duration, which is proportional to the braking distance.

If this pulse is generated during the duration of the gate pulse 6, the braking distance is shorter than the relative one Distance; So there is no risk of collision, so there is no reason to operate the quick brake.

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If, however, during the duration of the gate impulse 6 has not given a braking distance pulse, the brake is applied. Establishing presence or absence a pulse within the gate pulse 6 for distance evaluation is through a coincidence circuit carried out, which is designed in positive safety technology.

Above were the general punctures to be performed Are defined. To achieve these punctures, a certain number of elementary puncture blocks are used, which are shown schematically in FIG.

On board the vehicles are:

- security transmitter 19, security receiver 18,

- Obtaining the synchronization pulse 4,

- Generation of the position impulse 1,2,3,5,

- Gate impulse for distance evaluation 6,

- Generation of the braking distance pulse 11,12,.

- Coincidence circuit 14 *

The control center (FCC) contains:

- transmitter 20, receiver 21,

- Clock generator 22, for generating the synchronization pulse

In addition, each train is equipped with the following to detect certain system malfunctions:

- a test device for the detector f "v die Markings and for the transducer of the

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speedometer, I ¹ , - a test device for the transmission path

That in Pig. 1 block diagram shows two independent chains to secure against;. = collisions recognize; the mode of operation of a chain is examined, then the mode of operation of the two chains common parts.

The generation of the position pulse (Pig, 1): The output of the detector 1 for the markings supplies pulses which are counted in two counters: a binary counter 2 and a pseudo-random counter 2 ·. -

The content of this counter fc4.2 £ is compared to one the synchronization pulse at the output of the pulse recovery stage 4 delayed pulse 3.3 * converted by means of a downward counting counter that is controlled by a clock sequence of the clock generator. ^. This backwards counting counter is initially based on the value of the counter of the markers are set as soon as the sync pulse is received, and the counting backwards with the beat of the clock begins immediately. When the counter has reached the state "O *", a pulse of 4 ms duration generated.

A coincidence circuit 5 checks whether the pulses at the outputs of the two counters occur simultaneously.

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If this is the case, the circuit generates a pulse of 4 ms duration, which is sent to the transmitter 19. In the opposite case, rapid braking of the vehicle is initiated via 7,14,15, and to the Control center will send a security alarm on 9.19; so there is no transmission of a Position pulse on this chain.

gorimpuls for the removal rating (Fig l.): The the distance between two vehicles corresponding square-wave voltage is generated by a flip-flop 6 ( "AND" function with back looped fuse) your set to logic "I ¹¹ caused by the position pulse, the Resetting to the logical state · Ο ^Μ by the output signal of the receiver, the course of the signals is shown in FIG.

The timing diagram for generating the braking distance pulse is shown in FIG.

The true speed of the vehicle is determined by counting the pulses on the speedometer's perforated disk 10 calculated during a certain period of time, for example 300 ms, before the occurrence of the position pulse is located; this time is obtained by reading the downward counting binary counter, which is used to generate the position pulse.

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Now the expression for the braking distance was of the form (see also Pig. 3 -F) J

CJ = aV ² + bV + c
V is the speed, a, b, c are coefficients.

• * ι

The reverse equation gives a maximum speed depending on the braking distance:

^v m ^s r? r - 4 a (c - cf)

δ = X _t (see Fig. 3-F).

The generator of this function V _m (o) is a memory whose input signal is a number that is linear with time X ₄ . increases. The increase in ο is set in motion by the position impulse. The output voltage of the memory (FIG. 3 - curve G) is a variable that increases continuously with time. As soon as V _m »V (V is the true speed of the vehicle), an impulse is generated.

This pulse is delayed compared to the position pulse by a time that is proportional to the braking distance (curve H). ... · ■■

One checks with each episode by means of an "AND ^M gatea 14. to secure whether it is during the Torimpuleee for the

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Distance assessment has given a braking distance pulse. In the opposite case, the emergency braking (FU) triggered because there is a risk of collision.

Two safety chains are provided in each vehicle; each of which is equipped with a transmitter 19 and a receiver. The control center (PCC) is with two Transmitter-receiver arrangements 20, 21 equipped for each Chain for the whole of the vehicles.

The position pulses are amplitude-modulated by the vehicles transmitted by means of an antenna which is coupled to the transmission line laid on the ground.

These pulses are received from this transmission line by the receiver 21 of the control center and immediately transmitted again by the transmitter 20 on the transmission line, with an additional synchronization ^{pulse via the "AND 11} gate 23 , which allows to eliminate (PCC) again received from the vehicles ^r .Impulse the relations established by the delay in the transmission path errors.

Kittels a coupled to the transmission line Antenna, all vehicles receive the transmission of the control center (PCC), namely the response pulses of all Vehicles and the synchronization pulse.

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In general, the anti-collision function is secured by using self-monitoring for the complex functions and through, the positive Sieherungsteehnik achieved for the elementary punctures.

Detection of malfunctions in the device according to the invention takes place in the following way:.

Disturbances in the detectors are recognized by a monitoring circuit of the detectors I ¹ . This circuit measures the length between the markings by means of a counter and the perforated disk of the speedometer 10 and checks whether this length is always in the vicinity of a constant value.

The reverse case corresponds to a fault in the detector 1 for the markings or the perforated disk 10. A signal is then sent to the "AND" gate 7 for the Backup directed.

A circuit with self-monitoring is used to generate the position pulse. The same function is implemented twice, the output signals are compared with one another by a coincidence circuit using positive safety technology. The second circuit is indicated schematically by the block 100, which is connected to the first circuit by the coincidence circuit 13, the “OR ¹¹ gate 16 and the S.

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Fuse is connected.

A circuit with self-monitoring is also used to generate the braking distance pulse, this function however, it is only formed once within each safety chain. Indeed, the effects are in the system if this function is disturbed, it is less critical than for the position pulses.

The disturbances in the transmission are detected by a monitoring circuit 8 of the transmission. This circuit 8 checks whether a synchronization pulse is transmitted 18 by a vehicle this pulse also returning from the control center (PCC) is received again. When the vehicle receives the impulse that it sent out again without a load it will also receive all further pulses perfectly because the transmission conditions are identical are. In the opposite case, the monitoring circuit 8 of the transmission found a transmission fault and sends a signal to the "AND" gate 7 for backup.

The fuse block diagram presented for protection against Collisions are justified in the area of the evaluation of the alarm signals.

The degree of functional safety of the plant is not dependent on the level of safety in the realization of the

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Security functions measured, but by the amount of Security in the detection and transmission of malfunctions in the device according to the invention.

In general and in contrast to the previously known security devices, interference is caused by coincidence testing detected, and the output voltage of the relevant circuits triggers the braking.

The circuit for determining the fault is itself designed in such a way that it triggers the braking itself in the event that it is disturbed.

These circuits are referred to as “intrinsically secured” or “positive fuse-technical ¹¹ ”.

In the circuit shown in FIG. 1, the safety circuits are implemented in negative logic. The output delivers the logic voltage value "0" as soon as the associated DOG ¹ * gate 7, 14, 14 'has a fault indicating a fault. Receives signal with ^w 0 ^H.

The rules used to maintain safety against collisions are the following: - Any determination of a risk of collision or a fault in the safety circuits has result in rapid braking of the vehicle. -All at the same time on both safety chains

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Any malfunctions will result in the immediate interruption of line 25.

Position pulse disturbance alarm:

The modules 7,9,19,21,24 are affected. In order to meet the aforementioned conditions, you have to have twice in each Chain, i.e. four times for each device, the generation of a position pulse is realized. This precaution is chosen in such a way that a vehicle which detects a fault in its safety device is not forced is to demand immediate braking across the board.

In fact, in the event of such a malfunction, the disturbed vehicle must be braked immediately, and the next one Vehicle is to be protected; a vehicle * which has a disruption of a safety chain of its cerates recognizes, so always immediately sends its true position to the next vehicle. If on the other hand If a fault is discovered in every security chain, one no longer protects the next one just for all cases Vehicle, but you trigger the immediate braking all along the line. This is the only one remaining possibility to protect the next vehicle.

As a malfunction of the detector for the markings or a transmission malfunction in a chain also increases

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lead to a disturbance of the position pulse, a Generates an alarm, the sum formed by the "AND" gate 7 in a negative logical combination of the following Represents states:

- Disturbance of the position pulse generation 5,

- Detector malfunction "! ',

- transmission disruption 8,

If one of these three malfunctions is detected in a chain on board the vehicle, it will be on the control center (PCC) securely transmits the fault alarm for this chain 9,19,21,24.

If you receive the alarm of chain 1 and chain 2 of a vehicle at the same time in the control center (PCC), so the vehicle following the one who reported both malfunctions is no longer protected. The control center (PCC) therefore commands immediate braking along the entire line via the transmit / receive circuit 26,27,28,17.

-Unlike the previous alarm affects one Alarm for the braking distance pulse only the disturbed vehicle. When a vehicle no longer has its braking distance can determine, it does not endanger the safety of the other vehicles and thereby ensures its security that it stops immediately, the tax

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central (PCC) not affected.

Any disturbance of the braking distance pulse is determined in a secure manner by the coincidence circuit 13.

The gate impulse 6 for distance evaluation is carried out in terms of safety technology, so any disturbance of this puncture leads to the disappearance of the gate impulse, the ^M AND ^M gate 14 then triggers the immediate braking of the vehicle.

Blocking the alarm signals:

At the output of the "AND" gates 7,14,14 'for the fuse that controls the emergency braking, one has ^M OR ⁿ gatesl5, l6 that make it possible to block the control of the brake by safety remote control devices TC that are based on the one * dder? .d ± e other chain has an effect, but never on both chains at the same time. These remote control devices TC are designed in such a way that any failure of these remote control circuits or any simultaneous transmission of two remote control commands results in the disabling of the alarm signals.

These disabling of the alarm signals allow a vehicle to continue driving with a defective safety tag chain. Permission to do so can only be granted if there is sufficient information in front of and behind the vehicle

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Safety distance has been created, and this only in order to lead this vehicle back to the parking area So you always have a safety chain to protect the vehicles. When a second alarm occurs, amn is forced to use the next vehicle to drive this vehicle to the parking area create, the latter pushing the former.

The transmission of the alarm signals in the event of a fault in the position pulses' 9 is carried out securely and uses the same transmitter 19 as the position pulse itself, 21, 24.

In the case of the present specific embodiment is used for the first 300 ms of the anti-collision time sequence, it is the time it takes for the two synchronization pulses to be sent out by the Control center (PCC), corresponding to 2 β (see Fig. 4), separates.

When the vehicle receives the synchronization pulse, it transmits via the transmitter IiSBeinen to this synchronizing pulse delayed pulse after a time equal to its identification number 9 corresponds to (see Fig. 4)

The alarm signal is transmitted to the control center (PCC), whereby the transmission of the pulse via the

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Chain that generated the alarm is suppressed.

The signal received by the control center (PCC) usually has the one in Pig on each chain. 4 shown Setup when all vehicles are on the route.

If there is an alarm on either of the two safety chains of a certain vehicle, you can observe the disappearance of the in the control center (PCC) Alarm signal on the corresponding route.

The control center (PCC) also consists of two

Transmitters / receivers and the device for generating the synchronization pulse, a logic safety circuit 25 that decides the immediate braking across the board if there is an alarm in both chains of a vehicle at the same time, a manual control device is assigned to immediately interrupt the line TC, this command is ^{fed to the 11} AND "gate 26.

The command for immediate braking along the entire line is carried out safely and is carried out by means of a Transmitter 27, which transmits an unmodulated carrier frequency, namely the Safety frequency, radiates. All vehicles set this frequency by means of an antenna and a receiver

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28- fixed. When a vehicle receives this frequency, if it works normally, if not, it applies its quick brake. If the control center (PCC) has the immediate Braking all along the line is decisive, it is sufficient to interrupt the transmission of the safety frequency.

It can be of interest to block a route section to all vehicles that are on it Arrive section without affecting the vehicles that have already passed this section. For this purpose a. Simulated vehicle that stopped at this point. This can be, for example, the blocking of a switch, the protection of a repair on the route, act as an interruption zone of the transmission line, etc.

In order to simulate the vehicle stopped on the route, the control center (PCC) adds next to the Synchronization pulse and the position pulses of the vehicles on the lane at the transmitters the control center a position pulse that is generated there and the response pulse of a corresponds to a fictitious vehicle that has been stopped on the route. The position of this impulse in the pulse sequence to secure against collision defines the point of the route where the vehicle "

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is simulated.

In an analogous manner, it is necessary to issue warning pulses for vehicles in the parking area simulate to avoid immediate braking on the line if not all vehicles on the main route are. This simulation is carried out securely: you make it impossible to drive a vehicle onto the To bring the main route, whose alarm signals are simulated. For this purpose the code numbers of the parked vehicles entered directly at 24, so that by removing the appropriate alarm signals changed list becomes complete again.

Finally, the position counters, which are used to generate the position pulses, are reset to the Terminals, on arrival or departure, carried out.

It goes without saying that the present invention is not limited to that described and illustrated above Embodiment is limited, but that you can provide for this other embodiments without to depart from the scope of the present invention.

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Claims (6)

PATENT CLAIMS Cl. j Safety device against collision for vehicles that travel on their own route, this device having safety chains that are connected to a control center, further devices for determining the distance between two consecutive vehicles and for determining the safety distance between two vehicles in order to brake one Vehicle or the interruption of the transmission line if the distance between two successive vehicles is less than the safety distance, or in the event of a fault in a safety circuit, characterized in that it has a counting device by recognizing markings (1,2,2 ») , which are arranged along the route, also a computing device (3,3 ') for determining the distance of the vehicle from a predetermined starting point and a device (4,4 ») for converting this distance into a corresponding time period, with a time stamp that consists of a synchronization pulse which is received by all vehicles to generate a position pulse which is transmitted by all vehicles and received by all vehicles, that the determination of the distance between a vehicle and the immediately preceding one - 29 - 409833/0683 Vehicle is carried out by comparing the position pulses, and that the safety device of each vehicle compares this relative distance with the vehicle's braking distance to obtain the Triggering the vehicle's braking as soon as the relative distance becomes lower than the braking distance. 2. Safety device according to claim 1, characterized in that the braking distance from the true speed of the vehicle is determined by a speedometer with a perforated disc (10) is determined, which is its output signal to a Function generator that is set in motion by the position pulse and that provides an output signal outputs as soon as the function generator (ll) reaches the true speed, and that the braking of the Vehicles is triggered if the signal of the function generator (11) is not included in the period which corresponds to the distance between this vehicle and the vehicle immediately ahead separates. 3. Safety device according to claim 1, characterized in that the generation of the alarm is effected by a position alarm (7.9 _f 19) - 30 - 409833/0683 which is triggered separately or in conjunction with a fault in the detector (l ¹ ) for the markings, a fault in the counter (5) for the markings or a fault in the transmission path (8) that this fault (9, 19) is transmitted to the control center • and that the control center evaluates the alarm signals. 4 safety device according to claim 1 to 3, characterized in that the functional reliability of the safety chains for the position and braking distance calculation based on the detection of errors is ensured, with the functions have been divided and by self-assured checking of the coincidence of the output signals "of the divided Functions, and that the lack of coincidence indicates a malfunction or risk of collision and the Braking causes. 5. Safety device according to claim 4, characterized in that the division of the Functions is ensured by two chains (2.2 ·) which are not symmetrical to one another. 6. Safety device according to claim 1 to 5, characterized in that gee has two complete safety chains in every vehicle, as well as two complete safety chains in the control center (PCC) includes that the security chains in - 31 - 409833/0683 are assigned to each other in a speaking manner, and that the signals supplied by these security chains are compared for coincidence (13) to improve the reliability of the device, and that the simultaneous presence of an alarm on each safety chain causes immediate braking on the whole line triggers. 7 · Safety device according to claim 1 to 6, characterized characterized in that the command signal for immediate braking across the board from the control center (PCC) is sent out by means of a logic circuit that is connected to a transmitter (27), which transmits on a security frequency picked up by a receiver (28) in each vehicle, and that any interference in the reception of the transmitter signal on board the vehicle triggers the emergency braking of the same (17). 8 · Safety device according to claim 2, characterized in that the markings Are metal plates, and that the associated detectors act electromagnetically - 32 409833/0683 3 *. Blank page