Auto Locomotive Alarm

Almost any known encoding method can be used to encode a signal. However, in Russia and the CIS countries , two methods of coding ALSN signals are used: pulse numerical, based on the transmission of a series (bursts) of alternating current pulses (information carries the number and duration of pulses in a burst), and frequency, in which alternating current of a certain frequency is continuously transmitted (information carries the frequency ). On land railways, pulse coding is used and for the transmission of additional information in some systems, frequency, in subways - only frequency. On high-speed railways, the ALS-EN system with double phase difference modulation of the carrier frequency is used.

The signal is transmitted along the rail circuit . The signal current is supplied from the transmitter to the train via one rail, flows through a pair of wheels through the closure rails and returns to the transmitter through the other rail. In this case, the rails and wheelset form a frame with a current, the magnetic field of which is captured suspended in front of the first wheelset at an altitude of 110-240 mm above the rails of the receiving coils. On the sorting hills, where there are cars in front of the locomotive, and therefore it is not possible to transmit a code signal in front (the rail circuit is closed by wheel pairs of cars, and the signal current does not reach the locomotive), coding follows - the signals are sent from behind. In the subway with the DAU system (two-way coding), signals for reliability are transmitted both in front and after.

In rare cases (short rail lashes, low resistance of the ballast layer, in which a significant part of the signal current flows through the ballast and does not reach the locomotive), the signal can be transmitted not along the rails, but along a special loop laid along them. Currently, work is underway on the development of systems for transmitting traffic signals to a locomotive using radio communications (for example, the ALSR system).

ALSN locomotive equipment (now universally replaced by the KLUB-U electronic complex locomotive safety device, which, however, has the same principles for receiving and indicating ALSN signals) contains: receiving coils, a filter , an amplifier , a decoder, as well as a locomotive traffic light and vigilance handles. The filter installed at the input of the amplifier passes only code alternating current, cutting off all other currents - interference from radio communications, locomotive electrical equipment, etc. Code current on non-electrified and 3 kV DC lines has a carrier frequency of 50 Hz. On lines electrified with alternating current voltage of 25 kV and a frequency of 50 Hz, this is unacceptable due to the influence of traction current on the ALSN, therefore, code-current with a carrier frequency of 25 Hz (in some sections - 75 Hz) generated at signal point converter . Locomotives that can travel to areas with different code current frequencies ( diesel locomotives , VL82 M dual-supply electric locomotives) are equipped with toggle switches for switching the filter frequency - 25/50 Hz, and the signal signs “ALS-50” and “ALS” are installed at the borders of these sections -25 "or, for example, shields, on the one side of which is written" 25 ", on the other -" 50 ".

Generates code combinations a special device at the signal point - code path transmitter. A conventional KPTSh transmitter (plug-in) consists of an asynchronous electric motor with a gearbox rotating the cam shaft, and contacts closed by this shaft. Depending on what code the signal point should transmit, alternating current is supplied to one or another KPTSh contact, and from them it enters the rail circuit. Contacts “Z” are closed three times for about 0.3 seconds with intervals between closures of 0.12 seconds (small intervals), followed by an interval of 0.57-0.8 seconds (large interval) and the code combination is transmitted again. This is how the code combination corresponding to the green light at the traffic light is transmitted.

The code combination corresponding to the yellow fire is created by the “G” contacts and consists of two pulses, the “KZh” code combination transmitted during the red light at the traffic light is one. The duration of the pulses varies slightly depending on the type of KPTSh, their types are always different on adjacent block sections and the change in pulse duration is a sign by which CLUB-U determines the change of block sections. There are also electronic transmitters and other devices that transmit exactly the same code signals. The exact data for one of the most common transmitters (KPTSh-5) are shown in the figure “Coding of ALSN signals”.

The decoder decodes the code combinations, generates the signals of a locomotive traffic light, controls the shutdown of the EPA in violation of traffic safety. There are two main modifications to the device: the DKSV-1 relay decoder and the DKSV-M microprocessor decoder, which works with frequencies of 25 Hz, 50 Hz, 75 Hz and does not require periodic check of the relay.

When receiving the “KZL” code combination, the corresponding red-yellow light burns at the locomotive traffic light. If the ALSN code signal is lost (ceases to be received) after receiving the “QOL” code combination, then a red light lights up at the locomotive traffic light - it is believed that the locomotive passed the red light of the traffic light and entered the rail circuit, which is still shunted by the train ahead. When the code signal is lost in the event of the burning of the fire “Z” or “G”, a white light comes on at the locomotive traffic light. Usually this means that the train has entered an uncoded path, or it reports a malfunction (malfunction of a signal point, broken rail circuit) or a sudden red light on a traffic light in front. If there is a traffic light ahead of a crossing or other dangerous place, the appearance of a white light requires an immediate stop.

In the sections St. Petersburg - Moscow and St. Petersburg - Buslovskaya of the Oktyabrskaya Railway, together with ALSN, the ALS-EN system is used, which uses two-phase phase difference signal modulation and a modified Bauer code (Vekovishchev code). Unlike the classic ALSN, ALS-EH controls the availability of up to five block sections in front of the train, which is necessary to ensure high-speed movement in this section. As in the ALSN system, in ALS-EN the encoded signal to the locomotive is transmitted along the rail circuit.

The classical system for monitoring vigilance and emergency braking, which is part of the locomotive descrambler ALSN, operates as follows. An electro-pneumatic valve for hitchhiking EPK-150 is installed in the cockpit. During normal operation, the ALSN supplies power to its electromagnet. If necessary, check the vigilance of the driver, the power is removed, air begins to escape from the time-delay chamber of the EPC through a special whistle. The whistle serves as a signal for checking vigilance. To stop the whistle, the driver must press the vigilance knob of the Republic of Belarus, while the power supply of the EPA electromagnet is restored, the time delay camera is again filled with air. As soon as air comes out of the time delay chamber, which takes 6-8 seconds, the pressure of this air can no longer be held by the EPA stall valve - the stall valve opens, releasing air from the brake line, which causes emergency braking. Immediately before the start of autostop braking, the contact opens in the power circuit of the EPA electromagnet and when the RB is pressed, the power of the EPA is no longer restored.

When receiving the code combination “Z”, vigilance is not checked, and the speed is practically unlimited (or limited at the level of the set speed or slightly higher). With any change in the signal of a locomotive traffic light to a lower resolution, a single check of vigilance takes place. When driving while receiving the code combination “G”, a periodic (after 15-20 s) check of the driver’s vigilance is carried out if the speed exceeds the controlled one, usually 60 km / h. When receiving the “QOL” code combination, a periodic check of vigilance is carried out at any speed, and at a speed above the threshold (60 km / h) unconditional emergency braking occurs. Thus, it is actually forbidden to drive a yellow signal at a speed of more than 60 km / h. When switching a locomotive traffic light to a red light (for example, when driving through a closed signal), a periodic check of vigilance is also carried out, and if the speed exceeds 20 km / h, unconditional emergency braking is performed. To control speeds of 20 and 60 km / h, signals are used from a 3SL-2M mechanical speed meter, an KPD-3P series electronic speed meter, or other speed measuring device.

This ALSN system, adopted on railways, cannot provide an acceptable level of traffic safety without human assistance (in the case, for example, if a driver in a sleepy state “mechanically” presses a vigilance button, he can bring the train to a closed signal at a speed of 60 km / h). More modern alertness monitoring systems use more sophisticated work algorithms, which differ in the use of different light and sound signals for checking alertness, the number and location of buttons and handles for confirming alertness, but generally perform the same task and control the same speeds.

The most famous and widespread of the complementary ALSN systems is UKBM, a device for monitoring the alertness of a driver. PSS (preliminary light alarm) lamps are installed on the remote control. If it is necessary to check the vigilance, the UKBM lights PSS lamps, which can be extinguished by pressing the vigilance knob. There are no sound signals. If the PSS is not repaid within 5-8 seconds, then the power is removed from the EPA, which cannot be restored by the regular vigilance handle. To stop the whistle of the EPA, you need to press the top vigilance handle, which you can press, only getting up from the chair.

More secure and perfect are the various ALS-ARS systems used in the subways of the former USSR. As a rule, these systems use a frequency code and a relatively large number of indications indicating the permissible speed in a given section, and in some cases also in the following.

A path sensor is installed at the signal point, which generates information about the state of the path lying behind it, an encoder that selects a frequency in accordance with this information, and a track generator that generates alternating current of the desired frequency. This alternating current is continuously supplied to the rail circuit, received by the receiving coils and decrypted by locomotive receivers. Locomotive receivers transmit information to the signal unit, which lights up the corresponding display with the maximum speed, compares the maximum speed with the current one and, if necessary, turns off the traction motors and performs braking. The current speed signal comes from the speed measuring unit and is also displayed on the board.

"*" - depends on the installed speed on the line and the structural speed of the car

Currently, the ALSN system is widespread on the Russian railway network, which, due to limited functional capabilities, is unsuitable for sections with high-speed traffic. For a number of reasons, the more advanced ALS-EH system was not widespread (with the exception of the high-speed section of Moscow - St. Petersburg). There are also systems that transmit information to the locomotive automation about the distance to the next signal to provide targeted braking of the train before the closed signal. The most common of these systems is the automatic control system for braking the SAUT . Today, a certain part of locomotives and SSPS are already equipped with the CLUB, a promising integrated locomotive safety device (there are various modifications: CLUB, CLUB-P, CLUB-U, CLUB-UP - the latter is intended for installation on the SSPS (Special self-propelled rolling stock) and therefore rated at 24 V ), which implements the functions of ALS and ALS-EN on a locomotive.

• Equipment for railway automation and telemechanics: Reference. In 2 tons Soroko V.I., Razumovsky B.A., Moscow, Transport, 1981.
• Guide to repair and maintenance of locomotive hitchhikers. Moscow, State Transport Railway Publishing House, 1956.