Brake system malfunctions: do-it-yourself diagnostics and elimination of identified breakdowns. Possible malfunctions of the brake equipment, ways to eliminate them Reduced travel of the brake pedal

Conditional abbreviations are accepted in the text:KM - driver's crane No. 394 (395);

KBT - auxiliary brake valve No. 254;TM - brake line;PM - nutrient line;shopping center - brake cylinder;LPC - low pressure cylinder;CVP - high pressure cylinder;GR - main tank;ZR - spare tank;UR - surge tank;BP - air distributor;ZK - spool chamber of the air distributor;MK - main air distributor chamber;RK - working chamber of the air distributor;UP - balancing piston;RD - pressure regulator;THEN - Maintenance;TR - Maintenance;EVR - electric air distributor;EPT - electropneumatic brake;DNC - train dispatcher

Possible malfunctions of the driver's crane No. 394 (395)

The increase in pressure in the TM at the positionIIdriver's crane handles. Possible reasons):

increased leakage in the surge tank or its connections;

violation of the density of the reducer diaphragm at the place of its attachment or a crack in the diaphragm;

omission of the gearbox valve due to its unsatisfactory grinding or dirt particles getting under the valve;

skipping of the spool due to a violation of grinding to the mirror or contamination of the lubricant;

clogging of the 0.45 mm hole in the stabilizer with the slightest pass of the gearbox valve;

clogging of the hole 1.6 mm in the body of the middle part of the tap. With this malfunction, overpressure will be observed on the TM pressure gauge. In turn, the UR pressure gauge will not show overestimation;

inaccurate positioning of the KM handle in position II due to wear of the gradation sector on the valve body, weakening of the crane handle on the rod, drawdown of the spring fixing the handle cam, working out of the handle along the square of the rod, driver error.

Driving a train with a recharged brake line is unacceptable. In the passenger train, simultaneously with the reloading of the TM, the reloading of the SR wagons takes place. The disadvantage of the air distributor No. 292 is that the air pressure in the TC during braking depends on the pressure in the ZR. If the pressure in the TM and ZR is allowed to increase by more than 5.5 kgf / cm 2 and the train continues to be driven, then in the case of service or emergency braking, significant pressure is created in the shopping center, which leads to jamming of the wheel sets of the entire train. The result is the formation of sliders, an increase in braking distance, a threat to traffic safety.

In a freight train, when the TM is recharged, the ZR is recharged, as well as the ZK and RK in the air distributor. The increased pressure in the CR does not lead to increased pressure in the TC during braking, since the cargo air distributors have a mode switch for loaded, medium and empty modes, which will stop filling the TC depending on the set mode.

But the increased pressure in the RC makes it difficult to release the brakes after service braking, as a result of which some air distributors, especially in the tail section of the train, do not go into the released position. To release the brakes, it is necessary to further increase the already high pressure in the TM, and this is unacceptable.

If, when driving the train, the pressure in the brake line turns out to be more than 7.5 kgf / cm 2, then after the compressors are turned off by the regulator, the pressure in the main tanks will begin to decrease. When the pressure in the GR becomes less than the air pressure in the TM, the train may self-brake at position II of the KM handle.

While driving the train, the locomotive crew must constantly monitor the air pressure in the GR, UR and TM. With the timely detection of the overpressure in the TM that has begun (in a passenger train no more than 5.5 kgf / cm 2, in a freight train - no more than 6.5 kgf / cm 2), the driver must turn the driver's valve handle to position IV, observing the readings of the TM pressure gauges and UR.

If at position IV of the KM handle:

overstatement pressure air pre abbreviated , then the fault is in the gearbox valve. You can continue driving the train at position IV of the KM handle and try to remove a particle of dirt that has fallen into the seat by lightly tapping the gearbox valve plug and press the valve to the seat. In addition, it is possible to tighten the stabilizer spring with an adjusting screw, thereby increasing the amount of air released from the SD into the atmosphere through the stabilizer, and then move the KM handle to position II. If it is not possible to eliminate the increase in air pressure, then it is necessary to return the KM handle to position IV and drive the train to the first stop, maintaining air pressure in the TM, periodically moving the valve handle from position IV to II, and then to position IV. In the parking lot, it is necessary to fix the locomotive with the sixth position of the KBT, close the combined valve, position V or VI of the KM handle to unload the UR and replace the gearbox from the non-working cab. Then it is necessary to move the KM handle to position I, open the combined valve, charge the TM, with the KM handle in position II, adjust the stabilizer (if the spring force has changed), perform a short brake test and continue driving the train;

overstatement pressure in TM and UR lengthwise huddles - spool passes air. You can tighten the stabilizer spring with an adjusting screw and return the KM handle to position II. If it is not possible to eliminate the increase in pressure, then, if possible, at the station or on a favorable track profile, it is necessary to stop the train with a service braking stage. At the parking lot, the KM and KBT handles must be switched to position VI, brake lock No. 367 must be turned off and the locomotive secured with a hand brake. On locomotives without blocking No. 367, the combined valve and the double traction valve should be closed, the KM and KBT knobs should be set to positions VI and the locomotive should be secured with a hand brake. Then proceed as follows. They replace the upper and middle parts of the crane from the non-working cab, turn on the blocking of brakes No. 367 (on locomotives without blocking, open the combined crane and the double traction crane), charge the TM, adjust the stabilizer (if the spring force has changed), perform a short test of the brakes, release the manual brake and continue driving the train;

going on decline pressure in UR and TM with actuation brakes trains. The reason is leaks in the UR through its connections either with the driver's crane, or with a pressure gauge. If it is not possible to eliminate the malfunction, then in order to clear the stage, it is allowed to switch to brake control from the rear cab, after having previously tested the brakes;

overstatement pressure in TM due to izlo ma diaphragm gearbox or violations density her mounts in corps - is determined by the output of compressed air through the atmospheric hole in the adjusting screw of the gearbox at position II of the KM handle. You can stop the overpressure of air by setting the KM knob to position IV, continuing to drive the train to the station. When the pressure in the TM drops below the charging one, you should briefly move the KM handle to position II, and after increasing the pressure in the TM to the charging one, again to position IV. In the parking lot, it is necessary to replace the gearbox from the non-working cabin by the procedure described for the case when the overpressure stops at position IV of the crane handle;

overstatement pressure in TM stop it elk, in UR and at position II , and at polo zheniya IV pens KM - pressure charger. The reason is clogging of the 1.6 mm hole. You should immediately move the KM handle to position V and stop the train. If the discharge of TM does not occur at the position V of the KM handle, then it is necessary to stop the train by emergency braking. At the parking lot, it is necessary to replace the upper and middle parts of the crane from the non-working cabin in the same way as the case described, when the overpressure in the TM and UR continues, charge the TM, test the brakes and continue driving the train.

Decrease in air pressure in TM at positionIIKM handles. Possible reasons:

error machinist . When the KM handle is shifted by about 8 degrees from position II towards position III, the feed of the UR from the GR through the spool and gearbox stops. When the KM handle is displaced by 10 - 20 degrees, UR and AC begin to communicate with TM through the check valve of the tap. In operation, there were cases of erroneous incomplete closing of the combined crane by the driver, as a result of which there is no normal replenishment of leaks in the TM;

blockage filter to nutritional valve gearbox . In this case, you can continue driving the train, maintaining pressure in the UR and TM by briefly moving the KM handle to position I. At the first stop, close the combined valve, position V or VI of the KM handle to discharge the UR, remove the gearbox and gasket, unscrew the filter and clean it. After that, assemble the crane, charge the UR and TM, test the brakes and continue driving the train. With this malfunction, you can replace the filter from the crane of the non-working cab.

Slow elimination of supercharge pressure. Causes: incorrect adjustment of the stabilizer; hole clogging 0.45 mm. It is necessary to clean the hole with a non-metallic object (for example, a pointed match).

Rapid elimination of overcharge pressure. Causes: incorrect adjustment of the stabilizer; fracture of the stabilizer diaphragm. Determined by the release of compressed air through the adjusting screw of the stabilizer. It is necessary to stop the train, if possible, at a station or a favorable track profile and replace the stabilizer from a non-working cab at position IV of the KM handle. Another reason - there were increased air leaks from the SD. In this case, after the pressure is reduced to the charging pressure, it is possible to increase the pressure in the TM. This malfunction is detected after the KM knob is moved to position IV.

IVafter the performed braking, the pressure in the UR and TM increases. Causes: skipping of the spool or inlet valve KM with unsatisfactory density of the UE. When these faults occur, an increase in pressure in the TM can cause the brakes to release. Therefore, when driving a passenger train, position III of the KM handle can be used as an overlap. When driving a freight train, the minimum braking steps should be avoided and when the pressure rises, use the VA position of the KM handle. If, after braking, before the prohibition signal, the pressure in the TM begins to increase, then emergency braking should be applied.

When setting the KM handle to the positionIVafterperformed braking, the pressure in the UR decreases andTM. Causes: leaks in the UR or through its connections, spool or UE seal leak. These faults cause an increase in the braking effect that is uncontrollable by the driver. Therefore, when adjusting braking, the minimum set discharges of TM should be performed.

After discharging the SD to the required value and according tosetting the KM handle to the positionIV the discharge of TM continues to a large value, and then there is a sharp short-term increase in pressure in TM. Cause: Insensitive balancing piston. This malfunction can lead to the release of the brakes of a part of the train, and with minimal braking steps with a discharge of UR by 0.3 kgf / cm 2, the pressure in the TM may not decrease at all.

It is very difficult and dangerous from the point of view of traffic safety to drive a train and control the brakes with the given KM malfunction. To clear the haul after the train stops, you can switch to brake control from a non-working cab. At the station, it is necessary to disassemble the faulty CM, carefully inspect it, and also wipe the UE and piston sleeve, lubricate them, and then assemble the valve and check its operation. The sensitivity of the UE must be monitored in the process of acceptance of the locomotive.

After reducing the pressure on the UR manometer by the required value by position V of the KM handle and moving it to position IV, the pressure observed on the UR manometer is briefly overestimated. Reason: the hole in the fitting from the UR to the driver's tap is narrowed. With this malfunction, the discharge of TM occurs by a smaller amount than the driver planned, which, in turn, reduces the braking effect. In the worst case, a malfunction can lead to a short-term increase in pressure in the TM. In this case, after the braking stage, it is necessary to briefly hold the KM handle in position III, and then transfer it to position IV.

Slow rate of discharge of UR and TM at position V of the KM knob. Causes: clogging of holes 2.3 or 1.6 mm; skip sealing UE. These faults can be identified when checking the CM during the acceptance of the locomotive at the depot.

When the KM handle is briefly placed in position V, the TM is completely discharged. Causes: the tube from the UR to the KM is frozen; “the hole in the fitting from the UR is blocked. If you cannot find the fault and eliminate it, then you need to switch to brake control from the rear cab.

Before looking for the causes of brake problems, make sure that the tires are in good condition and correctly inflated, that the wheel alignment is well adjusted and that the load is evenly distributed in the vehicle.

Vehicle pulls to one side when braking
Incorrect adjustment brake pads.
Non-simultaneous replacement of pads on both wheels of the same axle.
Unequal air pressure in the tires of the front wheels.
Seizures or deep scratches on the mirror of one of the front wheel brake drums.
Damaged, wet or oily front brake pad on one side.
The material of the front brake pad or the disc on the other side is badly worn.
Loose or loose front suspension parts.
The piston has scratches or has acquired an oval shape.
The caliper mounting bolts are loose.
Wheel bearing misaligned.
Brake fluid leak in one of the wheel cylinders.
Jamming of the piston of the wheel cylinder.
Blockage of the steel pipe due to a dent or blockage.
Different tire pressures.
Incorrect wheel alignment.
Incorrect pressure regulator settings.
Defective pressure regulator.

Squeal
Front brake pad wear - the noise is caused by the wear sensor rubbing against the disc.
"Polished" or dirty front pads.
Dirty or scratched disc.
Support plate bent.
Weakening of the return spring of the rear brake pads.
Ovality of the rear brake drums.
Lubrication of friction linings.
Wear of linings or the inclusion of foreign bodies in them.
Excessive brake disc runout or uneven wear.

Too much brake pedal travel
Lack of fluid in the master brake cylinder.
Air in the system.
Disk beating.
Brakes not adjusted.
Damage to the cuff of the master cylinder.
Fluid leaking from wheel cylinders.

Pedal fails
Lack or absence of fluid in the master cylinder reservoir. .
Defective master cylinder.

Springy when the brake pedal is pressed
Air in brake lines.
Worn out rubber brake hoses.
Loose brake master cylinder mounting bolts. Master cylinder defective.
Incorrect front or rear brake pad clearance.
The outlet of the tank cap is clogged.
Deformed rubber brake pipes.
Soft or swollen caliper seals.
Poor quality brake fluid.

Brake pedal vibrates when brakes are applied
Damaged, worn or misaligned wheel bearings.
The caliper is incorrectly installed.
Worn and not parallel disks.
Not the same thickness of all disks.
The drums have acquired an oval shape.

Jamming brakes
(manifested in a decrease in engine speed or excessive heating of the wheel disks after movement)
Incorrect adjustment of the output rod on the brake pedal.
Cylinder regulator blocked.
Jamming of the pistons of the working cylinders.
Worn front brake pads.
The parking brake does not release.
Clogged brake lines.
Incorrect clearance between shoe and drum. :
Blockage in the compensation hole of the master cylinder.
Swelling of the rubber cuffs of the main cylinder (all cylinders do not brake) or the cuffs of the wheel cylinders due to the ingress of mineral oil or gasoline into the system.
There is no free play in the brake pedal due to the incorrect position of the brake light switch.
The protrusion of the adjusting bolt of the vacuum booster relative to the mounting plane of the main cylinder is broken.

Clogged compensation hole in the master cylinder.
Seizure of the master cylinder piston.

Rear brakes lock up under light braking

Heavy tire wear.
Damaged or misadjusted brake force corrector.

Rear brakes lock up under heavy braking
Too high tire pressure.
Heavy tire wear.
The front brake pads are contaminated with oil, dirt or water, the master cylinder or caliper is faulty.

Reduced brake pedal travel
The thrust ring of the device for automatically maintaining the gap between the shoe and the drum does not fix the shoe in the braked state.

Incomplete return of the brake pedal after braking due to the weakening of the pedal return spring
Jamming of the movable seat of the hydraulic vacuum booster follower when returning to the lower position after stopping pressing the pedal.
Weak or broken brake shoe return spring.
Seizure of the piston in the wheel cylinder due to corrosion or clogging.
Swelling of the wheel cylinder seals as a result of the ingress of mineral oil or some other petroleum-based liquid.

Lots of pedal effort when braking
Worn pads.
Lubrication of brake pads.
Incomplete fit of brake pads.
blockage air filter hydraulic booster.
The diaphragm of the hydraulic vacuum booster chamber is torn.
The diaphragm of the movable seat of the hydraulic vacuum booster is torn.
The ball valve of the hydraulic vacuum booster piston leaks brake fluid, the pedal retracts.
Vacuum booster air filter clogged.
Jamming of the valve body of the vacuum booster due to swelling of the diaphragm or pinching of the seal of the booster cover or protective cap.
The hose connecting the vacuum booster and the engine intake pipe is damaged, or its fastening on the fittings is loose.
Swelling of cylinder seals due to the ingress of gasoline or mineral oils into the liquid.

Rattle or "squeak" in the brakes
Loose brake shield.
Poor contact of linings with drums.
The nuts of the support pins of the pads have loosened.

Large force on the handbrake handle
Lubrication of the brake linings with brake fluid flowing from the rear wheel cylinder.

The brake drums are heated when the foot brake pedal and the parking handle are released brake system
The wheel does not break.
Incorrect adjustment of the parking brake drive.
Lack of return of the pads and the spreading lever of the manual drive to its original position due to jamming of the cables in the guide tubes.

Doesn't hold parking brake
Large free play in the hand brake drive mechanism.

Insufficient braking performance
The brake booster is not working well.
Severe wear on the gaskets or front brake pads.
One or more pistons are stuck.
The front brake pads are contaminated with oil or grease.
The new front brake pads haven't worn in yet.
Worn or damaged master cylinder.
Leakage of brake fluid from the wheel cylinders.
Air in the brake system.
Damaged rubber seals in the main brake cylinder. ;
The rubber hoses of the hydraulic drive system are damaged.

Spontaneous braking when the engine is running
Air leakage in the vacuum booster between the valve body and the protective cap: destruction or distortion of the cover seal or poor fixation due to damage to the locking parts, wear of the seal, insufficient lubrication of the cover seal.

One wheel does not brake
The brake shoe rotates tightly on the support pin.
Lack of clearance between the lining of the shoe and the drum due to incorrect installation of the automatic adjustment stop ring.
Weak or broken rear brake shoe return spring.
Seizure of the piston in the wheel cylinder due to corrosion.
Swelling of the O-rings of the wheel cylinder due to the ingress of fuels and lubricants into the liquid.
No gap between pads and drum.
Violation of the position of the caliper relative to the brake disc when the bolts of fastening to the bracket are loosened.
Increased runout of the brake disc (more than 0.5 mm).

Uneven wheel braking
Shock absorbers don't work.
The camber angle of the wheels is violated (wear of the inner tracks of the tread).
Reduced air pressure in tires (great wear at the edges of the tread).
Increased air pressure in tires (great wear in the middle part of the tread).
The convergence of the front wheels is underestimated (wear of the inner tracks of the tread).
Increased toe-in of the front wheels (wear of the outer tread tracks).

Wheel runout
Wheel imbalance: uneven tread wear around the circumference, displacement of balancing weights and tires during installation, rim deformation, tire damage.
Increased clearance in the wheel bearings.

Brake system malfunctions

Brake malfunctions that occur during the operation of the car include: insufficient braking efficiency, not simultaneous action, poor release or jamming brake mechanisms, increased free or working stroke of the pedal, incomplete releasing of the wheels, strong heating of the discs and brake drums, increased effort applied to the brake pedal, skidding or withdrawal of the car when braking, creaking or vibration of the wheel brake mechanisms, spontaneous braking when the engine is running.

Insufficient braking efficiency excludes the possibility of a timely stop of the car under normal driving conditions, and in difficult situations to traffic accidents.

The nonsimultaneity of the action of the brakes does not allow to stop the car in a timely and correct manner, and leads to a skid when braking. Poor wheel release causes overheating of the brake mechanisms, rapid wear of the brake linings and, as a result, jamming or weak brake action.

The reason for the weak action of the brakes may be a lack of tightness of the pneumatic drive system, a violation of the adjustment of the drive and brake mechanisms, wear or oiling of the brake pads, insufficient pressure air in the pneumatic brake system.

The inconsistency of the action of the wheel brakes can be caused by: a violation of the adjustment of the drive or brake mechanisms, jamming of the rods, as well as clogging of hoses and pipelines.

Jamming of the brakes may be due to: breakage of the coupling springs or breakage of the lining of the brake shoes, jamming of the expander cams and drive rollers, malfunction of the brake valves.

Page 2

Spontaneous braking with the engine running can be caused by a malfunction of the vacuum booster, as well as clogging or blocking of the compensation holes of the main brake cylinder.

A defective vacuum booster must be replaced or repaired.

To determine clogging or overlapping of the compensation holes of the main brake cylinder of cars, remove the reservoir of the main cylinder and use a soft wire with a blunt end to probe the edges of the cuffs through the compensation holes. If the tip of the wire, without encountering elastic resistance, passes to a depth of more than 2 mm, then the hole is not blocked by the edge of the cuff. If the wire inserted into the compensation hole meets elastic resistance, disconnect the main cylinder from the amplifier. The release of the compensation hole after this indicates incorrect adjustment of the amplifier. If the compensation holes after disconnecting the amplifier remained blocked by the edges of the cuffs, remove and disassemble the main cylinder. The causes of the described defect may be swelling of the cuffs of the main cylinder, contamination of the mirror of the main cylinder, breakage of the return spring.

Brake hoses must not show visible cracks on the outer sheath and traces of chafing, they must not come into contact with mineral oils and lubricants that dissolve rubber (by strongly pressing the brake pedal, we check if swelling appears on the hoses, indicating their unsuitability).

Leakage of a liquid from connections of the main cylinder with a tank and from fittings is not allowed. If necessary, replace the bushings of the tank and tighten the fittings without exposing the pipelines to deformation.

Faults found during the inspection must be eliminated with the replacement of damaged parts with new ones.

Checking the performance of the vacuum booster

1. Press 5-6 times on the brake pedal when idle engine to create in cavities A and E the same pressure, close to atmospheric. At the same time, by the force applied to the pedal, we determine whether there are any jamming of the valve body 22 (Fig. 4).

2. Stop the brake pedal in the middle of its travel, start the engine. With a working vacuum booster, the brake pedal should “go forward” after starting the engine.

3. If the pedal “does not move forward”, we check the fastening of the tip 29 (Fig. 4), the condition and fastening of the flange 1 (Fig. 4), the hose to the tip and fitting of the engine inlet pipe, since loosening of the fasteners or damage to them sharply reduces the vacuum in cavity A and the efficiency of the amplifier.

4. In case of spontaneous braking of the car, we check the vacuum booster for leaks with the engine running, first with the fixed brake pedal released and then pressed. "Suction" of the protective cap 12 (Fig. 4) to the shank of the valve body and the hiss of the sucked air indicates insufficient tightness of the amplifier.

5. Even in the absence of “suction” of the protective cap, we check the condition of the seal 18 (Fig. 4), for which we carefully remove and then shift the protective cap 12 (Fig. 4) from the flanging of the hole on the cover 4 (Fig. No. 4).

6. With the engine running, shake the protruding shank of the valve body in the transverse direction with a force of 29.4–39.2 N (3–4 kgf); in this case, there should not be a characteristic hiss of air passing inside the amplifier through the seal 18 (Fig. 4) of the cover.

7. If the vacuum booster is not tight, disconnect the pusher 14 (Fig. No. 4) from the brake pedal, remove the protective cap 12 (Fig. No. 4) and put 5 g of CIATIM-221 grease between the seal and the flange of the cover and valve body, then check the condition air filter 15 (Fig. No. 4), if necessary, replace it and install the protective cap in place.

8. If in this way it is not possible to eliminate air leakage, then it is necessary to replace the vacuum booster.

Adjustment of a drive of brakes

The brake pedal free play with the engine off should be 3–5 mm. This value is obtained by adjusting the position of the brake light switch 6.

Rice. 6. Brake pedal:

1 - vacuum amplifier; 2 - pusher; 3 - brake pedal; 4 – brake light switch buffer; 5 - switch nut; 6 - stoplight switch; 7 – retractable pedal spring; 8 - master cylinder

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The interaction of employees of the locomotive and wagon economy when the brakes are applied or the locomotive crew claims insufficient brake pressure (breakage of supply pipes, end valves, disconnection of brake hoses, malfunction of air distributors)

If there was a spontaneous operation of the auto brakes, then in this case a short test of the auto brakes is carried out with a check of the state of the brake line by the action of the brakes of the two tail cars.
If, when the train is moving, the break signaling device is triggered and the traction mode is turned off due to self-braking and additional discharge of the line by air distributors, the train speed does not sharply decrease. The driver in this case is obliged to check the integrity of the brake line by setting the driver's crane handle to position III. Convinced of the integrity of the line by the absence of a rapid continuous decrease in pressure, the driver performs a braking stage and releases the brakes.
If the signal lamp lights up at the train stop and the traction mode does not turn off, which may indicate the overlap of the end valves in the train or arbitrary discharge of the brake line in the train. In this case, before the departure of the train, it is necessary to make sure that the signaling device is in good condition by giving a braking stage by reducing the pressure by 0.6-0.7 kgf / cm2 (the lamp goes out) and releasing the brakes. After that, the possibility of switching on the traction mode is automatically restored. In the event of a faulty signaling device, an abbreviated test of the autobrakes is carried out with a check of the operation of the brakes of two tail cars.
Reduced testing of the brakes is also carried out after any separation of the hoses in the train.
When the associated end valve is closed, braking will occur in the disconnected part of the highway and the train will stop if braking force will be greater than the thrust force.

When the opposite end valve is closed, air will be released from the head of the line, due to the additional discharge of the line, braking will spread further towards the locomotive. On a freight locomotive, the brake line break signaling device with sensor No. 418 is activated and traction is turned off.
After the end of the additional discharge of the line, the driver's crane will increase the pressure in the line and the air distributors will be released to the closed end valve. Behind the point of closing the end valve, the supply of leaks from the main line will stop and the air distributors of the freight train will be activated for full braking.

The peculiarity of cargo air distributors is that in almost all cases of power failure of the line when the end valves are closed, they are braked due to the fact that their spare tanks are disconnected from the line by check valves, which gives a rapid decrease in pressure in the line under the influence of leaks.

In all cases of detecting closed end valves after the train stops, it is necessary to release the brakes with the driver’s crane, open the end valve, perform a short test of the auto brakes and be sure to check the release of the brakes to the last car.

Braking in the train, which occurred with the train position of the driver's crane handle, is called SPONTANEOUS ACTIVATION OF AUTO BRAKES.

1. The reason for it can be a rapid decrease in pressure in the line in cases of self-disengagement, breakage and separation of sleeves, breakage of the outlet from the line to the air distributor, closing (shutdown) of the oncoming end valve or both end valves with the release of compressed air from the line through their control holes. This group of reasons is associated with a violation of the density of the highway.
2. Spontaneous operation of automatic brakes is also possible with a decrease in pressure in the line in cases of overlapping of the associated (backward) end valve, the formation of an ice or mechanical plug in the line.
3. Separate cases of self-braking occur as a result of unreliable release of the brakes due to their malfunction.
4. Spontaneous operation of autobrakes is possible during the transition from increased to normal charging pressure due to an accelerated transition rate (not repaired driver's crane stabilizer)
5. There are also cases of self-braking air distributors No. 483 in operation. They occur when there is a change in leakage from the brake line when driving along curves of small radius or arrows, as well as during a sharp dynamic impact on cars that have weakened fastenings of the working chambers of the air distributors or brake lines. This operation is most likely for the main part, in which the softness throttle hole is clogged, or due to the increased spring force, the softness valve does not lift and open.

Identification of the causes of spontaneous operation of the brakes in the train

Spontaneous operation occurred when the train was stopped, the cause of operation may be:

1. poor air permeability at the locomotive;
2. faulty or incorrectly adjusted stabilizer of the driver's crane (liquidation in excess of the charging pressure is faster than the established standards). The brakes are activated when the driver's crane handle is moved from position 1 to position 2;
3. defective air diffuser.

Identification of the reasons for the spontaneous operation of the brakes in the train must begin with checking the tightness of the brake network of the train, then, having disconnected the cars (the brake system of the cars), check the locomotive.

1. Find out at what pressure in the main reservoirs the brakes actuate. If operation is observed at the lower pressure limit of 7.5 atm., check the air permeability of the brake and power supply network of the locomotive.
The air permeability of the brake system is checked by opening the end valve on the locomotive at least 3 times (through the blocking device of the driver's crane). With a drop in pressure - the permeability is low, freezing, clogging of the supply or brake line is possible. Check the passage of air through the blocking device. After the compressors stop and when the pressure in the main tanks reaches at least 8 atm. On an electric locomotive, the compressors are turned off; on a diesel locomotive, diesel is stopped. The handle of the driver's crane is transferred to the VI position. The connecting sleeve is removed from the suspension and holding it open the end valve.
The handle of the driver's crane is transferred to position I. The time of pressure reduction in the main tanks from 6.0 to 5.0 atm is measured, which should be for tanks U = 1000 l. no more than 12 s. for the rest, the time increases proportionally.

2. If the operation occurs after 1-2 minutes, after the start of the holiday,
check the rate of liquidation over charge and the operation of the gap alarm
brake line, then - the density of the surge tank follow
in order:
release by holding the driver's valve handle in position 1 to the pressure in the surge tank from 6.5 to 6.8 kg / cm2, followed by transfer to the train position. The decrease in pressure in the surge tank from 6.0 to 5.8 kg / cm2 should occur in 80-120 s.
On a locomotive equipped with "TM", the signaling device should not work during the transition from high pressure to normal.
To check the density of the surge tank, charge the brake network to a normal charging network, turn the driver's crane handle to position IV. The density is considered sufficient if the pressure drop in the surge tank does not exceed 0.1 kg/cm2 for 3 minutes. Overpressure in the surge tank is not allowed.

3. Identification of faulty air distributors.
A faulty air distributor UEL No. 483 is detected by the following signs: it works when the brake network is charged, when the pressure in the spare tanks begins to equalize with the line pressure (the noise in the spare tanks stops) and then periodically works at certain intervals.
To identify such an air distributor, it is necessary to establish in which part of the composition it is located. To do this, the train is divided “in half”, the brakes of the head of the cars remain on, the rest are turned off by end valves. If a faulty device (the additional charging valve and the softness valve do not work satisfactorily) is located in this part of the train, then when charging after 3-7 minutes, the automatic brakes will spontaneously operate, leaving the fourth part of the cars from the head switched on, repeat the check.
Thus, a group of cars is installed in which the faulty device is located. Then, with the help of uncoupling valves, the air distributors are sequentially turned off and, having determined the faulty one, replace it.

Spontaneous operation occurred when the train was set in motion

The most common reasons for the activation of autobrakes are:

1. the presence of hidden air leaks in the brake system;
2. defective air distributor, condition No. 483 (sinking of the rubber seal at the valve of the chamber for additional discharge of the line, insufficient rigidity or discrepancy between the valve spring and the established dimensions)

1. Leaks are detected by outward signs by ear, by touch, by the presence of a roller of dust, dirt, by tearing of paint, in winter by the presence of frost, frost at the leak. When checking, it is necessary to inspect the condition of the coupling joints, threads, the presence of cracks, breaks in the line and supply pipes.
In addition, of great importance for the stability of the operation of any connection is the reliable fastening of the air duct of its branches, reservoirs and brake cylinders. Fastening violations entail a breakdown of the connections and, as a rule, leads to the operation of the brakes along the route.
Having found out the leak, you need to make sure that it leads to the operation of the brakes along the route. The check is carried out with a crowbar, which is wound up between the main and the center beam by pressing it down. If the coupling is poorly fixed on the line (on 2-3 threads), a bend occurs in the coupling joint, the leakage increases greatly, which leads to the brakes.
The quality of fastening of air ducts and brake fittings is checked by tapping the places of their fastening to the car frame with a control hammer.

2. To identify a faulty air distributor leading to
the operation of the brakes in the train, you need to know that it comes into action due to the oscillatory movement of air in the line from the impact. Moreover, the greatest effect of identifying a faulty air distributor is obtained by tapping the sleeves (250 mm from the end valve) and the main part of the device at the time of transition from overpressure to charging (when eliminating overcharge pressure).
After setting the minimum value for eliminating overcharge pressure (80 sec.), at the moment of transition from overpressure to charging pressure, it is necessary to tap with a hammer (crowbar) on the sleeves and devices of the air distributors on the locomotive and cars (on the body of the main part, the direction of blows is horizontal).
But since the time for tapping is limited by the time of elimination of supercharge pressure, tapping must be carried out at the command of the locomotive driver in a certain period of time, which is calculated by the formula:

T=Tlik. x 0.08,

where T is the desired tapping time (in minutes) T lik. - overcharge liquidation time.

EXAMPLE: T lik - 80 s. then T \u003d 80 x 0.08 \u003d 6.4 min. i.e. after 6 minutes, stop tapping and wait for the driver’s command to resume the check.

In the presence of a faulty air distributor, the brakes are activated, being in a braked state, the air distributor, after a certain period of time, releases air into the atmospheric opening of the main part. Usually a faulty air distributor is triggered 5-6 cars before the one where the hose was hit.
All identified malfunctions that lead to spontaneous operation of the brakes are eliminated and carried out full testing brakes, the driver is issued a new certificate VU-45.