For service braking, move the driver's crane handle to the V position and reduce the pressure in the surge tank by the required amount, after which the crane handle should be moved to the IV position. The first stage of braking is performed by lowering the pressure in the surge tank: in loaded trains - by 0.6 - 0.7 atm, on steep long descents - by 0.7 - 0.9 atm, depending on the steepness of the descent. If necessary, perform the second stage after at least 5 seconds after the cessation of air release from the line through the driver's valve.
If the valve has position VA, then after obtaining the necessary discharge of the surge tank with position V, it is allowed to hold the valve handle in position VA for 5-8 seconds before moving to position IV in order to stabilize the pressure in the surge tank in the shut-off position.
To prevent the depletion of autobrakes in a train when following a descent on which repeated braking is performed, it is necessary to maintain a time of at least 1 minute between braking to recharge the train's brake network. To fulfill this requirement, do not make frequent braking and do not release the autobrake at high speed. The time of continuous movement of a train with a constant braking step on the descent when the air distributors are turned on for the flat mode should not, as a rule, exceed 2,5 min. If longer braking is necessary, increase the discharge of the brake line by 0.3 - 0.5 atm and, after a sufficient decrease in speed, release the brakes.
If it is necessary to use full service braking, as well as in the process of adjusting braking when following a descent, do not discharge the brake line to a pressure below 3.8 atm. If, for any reason, when following the descent, the pressure in the TM is below 3.8 atm, stop the train, apply the auxiliary brake of the locomotive, then release the automatic brakes and charge the brake network in the parking lot before the train starts moving. If the pressure in the train line turned out to be lower than 3.8 atm at the end of the descent, and according to the conditions of the track profile, the speed of further movement will decrease so much that it will be necessary to release the automatic brakes, and in the time before the next braking it is possible to recharge the brake network to the set pressure, then stop the train for recharging is not required.
When the automatic brakes are fully released after service braking, hold the driver's crane handle in position I until the pressure in the surge tank rises by 0.5 - 0.7 above the charging one.
After emergency braking, release the auto-brakes in the freight train by moving the valve handle to position I until the pressure in the surge tank reaches 6.5 - 6.8 atm
After stopping the train with the use of automatic brakes, it is necessary to wait for the time from the moment the driver’s crane handle is moved to the release position until the locomotive is set in motion: after the braking stage - not less than 1.5 minutes with air distributors switched on to the flat mode, and not less than 2 minutes, with air distributors switched on to the mountain mode; after full service braking - Not less than 2 minutes with air distributors switched on to the flat mode, and not less than 3.5 minutes with air diffusers switched on to the mountain mode; after emergency braking in trains up to 100 axles - at least 4 minutes, more than 100 axles - 6 minutes.
5.23. Why is it necessary to reduce the pressure in the TM at the first stage of braking by at least 0.5 atm in a freight train and 0.3 atm in a passenger train?
The discharge of the brake line, set by the driver's crane to obtain the first stage of braking, must be no less than the additional discharge of the line performed by brake devices (passenger type - by 0.3 atm, cargo - by 0.5 atm). If the first stage of discharge by the driver’s crane is made less than the additional discharge, then the pressure drop in the TM through the air distributor will be greater than in the surge tank of the driver’s crane, and in the shutdown position with power, the valve will increase the pressure in the TM and uncontrolled release will occur. To obtain reliable braking and release by all devices, it is necessary at the first stage of braking to reduce the pressure in the TM by at least 0.5 atm in cargo and 0.4 atm in passenger ones.
In freight trains, when following a free section or on a green light on a flat track profile, a minimum braking step is allowed by reducing the pressure by 0.3 atm. A long exposure to such a stage can lead to the release of individual brakes, however, the safety of following will not be violated.
5.24. The procedure for checking the operation of the brakes along the route (clause 10.1.1. instr. No. 277, order No. 66 / N of 06/30/1999).
The operation of the auto brakes on the way should be checked at a speed of 40-60 km/h. If there are warnings about the speed, or it is impossible to develop a speed of 40 - 60 km / h in the established places, check the brakes for braking to a complete stop, followed by a check of the brakes on a favorable profile in the prescribed manner.
Checking the operation of automatic brakes along the route is carried out by reducing the pressure in the surge tank of a loaded freight train and a single following locomotive by 0.7 - 0.8 atm, in empty freight, passenger-and-freight trains by 0.5 - 0.6 atm, set for testing the brakes. When checking the operation of the brakes, it is prohibited to use auxiliary and electric brakes on the locomotive in all trains.
After the appearance of a braking effect and a decrease in speed by 10 km / h in a freight loaded train, a freight-passenger, passenger and single locomotive and by 4-6 km / h in an empty freight train, release the brakes. Said descents must occur at a distance not exceeding that specified by local regulations. The release of the brakes after checking on the way should be done only after the driver is convinced of their normal operation.
If, after the first stage of braking, the initial effect is not obtained in a passenger train within 10 s, in an empty freight train up to 400 axles long and a passenger-and-freight train within 20 s, in other freight trains within 30 s, immediately perform emergency braking and take all measures to the train stop.
The operation of the automatic brakes along the train route should also be checked after a complete or shortened test of the brakes, turning on and off the automatic brakes for individual cars or a group of cars, when switching from EPT to automatic, if the travel time on the EPT was 20 minutes or more.
If it is necessary to check the operation of automatic brakes in unspecified places, it is allowed to perform it, as a rule, on the station tracks or when leaving the station on the first stage, which has a platform or descent, taking into account local conditions. In these cases, the effect of automatic brakes may be assessed by the time of speed reduction by 4–6 km/h in an empty freight train and by 10 km/h in other freight trains and single locomotives. This time is set in local instructions.
In passenger trains, first check the operation of the automatic brake, and then the EPT. To check the operation of the EPT along the route, perform a step until the pressure in the TC of the locomotive is 1.0 - 1.5 atm.
Move the control valve of the auxiliary brake to the last braking position. On locomotives equipped with a driver’s crane, in which the transmission of the control command from the control body to the actuators is carried out electrically or in another way (except mechanically), the auxiliary brake control crane in the non-working cab must remain in the train position;
Apply the automatic parking brake (if equipped);
After setting the maximum pressure in the brake cylinders, turn the locking device key and remove it.
b) on locomotives not equipped with a blocking device or with a brake blocking device No. 267:
If there is an electro-pneumatic brake, turn off the power control switch for this brake on the control panel;
Discharge the brake line to zero by setting the control element of the driver's crane to the emergency braking position;
Move the handle of the combination valve (if equipped) to the double pull position. If the lock has the function of automatic disengagement of the driver's crane with the brake line, when turning the key of the locking device, do not perform this operation;
After setting the maximum pressure in the brake cylinders, turn the key of the brake locking device No. 267 and remove it;
Close the disconnect valve from the auxiliary brake valve to the brake cylinders.
On electric locomotives of the ChS series, the disconnect valve on the air duct from the auxiliary brake valve No. 254 to the brake cylinders must be open.
Make sure that the brake cylinders are filled to full pressure and that there is no unacceptable decrease in pressure in the brake cylinders (it is allowed to reduce the pressure in the brake cylinders by no more than 0.02 MPa (0.2 kgf / cm 2) for 1 min.)
When the locomotive is equipped with a parking (hand) brake drive and pressure gauges for the brake cylinders in the body, which make it possible to control the inhibited state of the locomotive in the process of moving to another control cabin, the presence of an assistant driver in the leaving cabin is not required.
In the cab being put into operation, the driver must:
a) on locomotives equipped with a blocking device:
b) on locomotives not equipped with a blocking device or with a brake blocking device No. 267:
Open the disconnect valve on the air line to the brake cylinders from the auxiliary brake valve;
Transfer the control element of the driver's crane from the brake position to the train position, and if there is a brake lock No. 267, insert the removable lock key into the socket and turn it, charge the surge tank to the charging pressure;
Open the combined valve, charge the brake line to the charging pressure;
Move the control element of the auxiliary brake valve to the train position.
b) on locomotives equipped with a blocking device:
Insert the key into the locking device and turn it, turning off the lock and activating the controls;
Transfer the control element of the driver's crane from the brake position to the train position and fill the surge tank and the brake line to the charging pressure;
Release the automatic parking brake (if equipped).
The driver's assistant during the transition must be in the left cabin and, using the pressure gauges of the brake line and brake cylinders, control the inhibited state of the locomotive until the brake line is charged from the working cabin. In the event of a spontaneous release of the locomotive brake, the driver's assistant must activate the parking (hand) brake.
On locomotives equipped with a parking (hand) brake drive in only one cab, the assistant driver during the transition must be in a cab equipped with a parking (hand) brake drive.
On locomotives equipped with an automatic parking brake, an assistant driver in a cab equipped with a parking (hand) brake drive is not required.
After the locomotive has been hitched to the train, the presence of the driver's assistant in the cab being left is not required.
Having completed all the operations for the transition to the working cabin, the driver must:
Before setting the locomotive in motion, check, by controlling the pressure gauge of the brake cylinders, the operation of the auxiliary, and then automatic brakes;
After setting the locomotive in motion, check the operation of the auxiliary brake at a speed of 3-5 km/h until the locomotive stops.
238. For service braking, it is necessary to transfer the train brake handle from the train position to the brake position and reduce the pressure in the SD from the set charging pressure by the required amount, after that, move the train brake handle to the power-off position.
The first stage of braking must be performed by reducing the pressure in the UR:
in loaded trains - by 0.6-0.7 kgf / cm 2;
in loaded trains on steep long descents - by 0.7-0.9 kgf / cm 2, depending on the steepness of the descent;
in empty trains - by 0.4-0.5 kgf / cm 2.
On a flat track profile with a descent of up to 0.008 ‰, when following the green light of a traffic light or along a free stretch, the first stage of braking (except for checking the operation of automatic brakes) is allowed to be performed by reducing the pressure in the UR by 0.3-0.5 kgf / cm 2.
If necessary, perform the second step after at least 5 seconds.
If the train brake handle has the VA position, then after receiving the necessary discharge of the UR with the V position, it is allowed to hold the train brake handle in the VA position for 5-8 seconds before moving to the overlap position with power to stabilize the pressure in the UR in the overlap position.
239. Repeated braking must be performed in the form of a cycle consisting of braking and transferring the brake handle to the overlap position to achieve the required speed of the train, after which it is necessary to release the automatic brakes in accordance with the requirements of paragraphs 243, 244 of this Instruction.
If after the release of the automatic brakes of the train with the flat mode of the air distributors, the time for the pressure to change from increased to normal charging was less than 1 minute, then the next stage of braking must be performed by reducing the pressure in the UR by 0.3 kgf / cm 2 more than the first braking.
240. In order to prevent depletion of automatic brakes in a train when following a descent on which repeated braking is performed, it is necessary to wait at least 1 minute between braking to recharge the train's braking network. To fulfill this requirement, do not allow frequent braking and do not release the autobrakes at high speeds. The time of continuous movement of a train with a constant braking step on the descent, with the air distributors switched on in the flat mode, should not exceed 2.5 minutes. If more prolonged braking is necessary, it is necessary to increase the discharge of TM by 0.3-0.5 kgf/cm 2 and, after a sufficient decrease in speed, release the automatic brakes of the train.
The time of continuous movement of the train with a constant braking step on the descent, with the air distributors turned on in the mountain mode, should not exceed 10 minutes, then the braking force is adjusted upward or downward in steps depending on the speed and track profile.
241. On long descents of 0.018 ‰ and steeper, when controlling the automatic brakes of a train with a charging pressure of TM 5.6-5.8 kgf / cm 2, the first stage of braking must be performed at a speed set in local instructions and regime maps, by reducing the pressure in UR by 0.7-0.8 kgf / cm 2, and on slopes steeper than 0.030 ‰ - by 0.8-0.9 kgf / cm 2.
Further, the braking force must be adjusted depending on the speed of the train and the track profile. At the same time, do not allow full release of autobrakes if the train speed exceeds the set speed before the end of recharging the brake network and performing repeated braking.
If it is necessary to use full service braking, as well as in the process of adjusting braking while following the descent, it is not allowed to discharge pressure in the TM below 3.8 kgf / cm 2.
If, for any reason, when following the descent, the pressure in the TM is lower than 3.8 kgf / cm 2, it is necessary to stop the train, activate the locomotive brake, then release the automatic brakes and charge the brake network in the parking lot before the train starts moving (or for at least 5 minutes if the train is held by the locomotive brake).
If the pressure in the TM of the train turned out to be lower than 3.8 kgf / cm 2 at the end of the descent, and according to the conditions of the track profile, the speed of further movement will decrease so much that it will be necessary to release the automatic brakes and, in the time before the next braking, it is possible to recharge the brake network to the set pressure, then It is not necessary to stop the train to recharge the auto brakes.
After the train passes a long descent and transfers its brake network to normal charging pressure at the station, the inspectors of the cars are required to check the release of all automatic brakes in the train and switch the air distributors in the train to the flat mode.
242. When a freight train is traveling at a speed of more than 80 km / h and a yellow light appears at a locomotive traffic light, it is necessary to put the brakes into action by reducing the pressure in the UR: in a loaded train - by 0.8-1.0 kgf / cm 2, in an empty - by 0.6-0.7 kgf / cm 2. At a lower train speed and longer block sections, braking should be started, taking into account the speed and effectiveness of the train's brakes, at an appropriate distance from the traffic light.
243. In freight trains with a charging pressure in the TM from 4.8 to 5.5 kgf / cm 2 with the full release of the auto brakes after service braking, it is necessary to hold the train brake handle in position I until the pressure in the UR increases by 0.5-0.7 kgf/cm 2 above the charger (on locomotives of the CKD series - up to the charger). After reducing the pressure to normal charging, if necessary, repeat the indicated overpressure.
244. On short descents, where repeated braking is applied and the flat mode is switched on on the air distributors of the train, the release of the train brakes between repeated braking must be carried out by moving the train brake handle to position I and holding it until the charging pressure in the UR.
If there is time between repeated braking for the transition from increased pressure in the line to normal charging pressure, then the release of autobrakes between repeated braking must be carried out in accordance with paragraph 243 of this Instruction.
245. After emergency braking, to release the automatic brakes of the train, it is necessary to move the handle of the train brake to position I until pressure is obtained in the UR: 3.0-3.5 kgf / cm 2 - without a stabilizer, 6.5-6.8 kgf / cm 2 - in the presence of a stabilizer (on locomotives of the TE33A series - up to 6.0-6.2 kgf / cm 2). After that, move the train brake handle to the train position.
246. When the length of the freight train is from 100 to 350 axles, simultaneously with the start of the release of the automatic brakes of the train, it is necessary to brake the locomotive (if it has not been braked earlier) with a pressure in the TC of 1.0-1.5 kgf / cm 2 and keep it in a braked state for 20-30 seconds, then release the locomotive brake in stages.
The use of a pneumatic or electric locomotive brake when the train brakes are released (to compress the train) is carried out by the driver, if necessary, when driving a train with cars of different loads, after determining the first check of the brakes for efficiency and the existing reactions of the train when the brakes are released.
For freight locomotives with cast-iron blocks and double-sided pressing on the wheel, the locomotive brake must be applied in advance before the release of the train brakes by smoothly increasing the pressure in the locomotive's TC to 0.5-0.7 kgf / cm². After transferring the train brake handle to the released position, the pressure in the locomotive's TC should be gradually increased to 1.5-2.0 kgf/cm², depending on the weight of the train.
The value of the required pressure in the TC or the current of the electric brake for locomotives of the TE33A, KZ8A series, depending on the pressure (ts) on the axle and the braking force of the locomotive, is set by local instructions for automatic brakes, based on the results of experimental trips.
It is necessary to use a locomotive brake to compress the train when the brakes are released on breaks in sections of the haul, on a broken track profile, when the brakes of a loaded train are released on the descent, and also in winter at low temperatures (when the propagation time of the release wave increases and there is a possibility of TM freezing).
247. In trains with a train with a length of more than 300 axles, it is not allowed to release the automatic brakes of the train at a speed of less than 20 km / h to a complete stop. As an exception, when following a descent with a speed limit of 25 km/h or less, the release of the train's automatic brakes should be performed in advance (15-20 seconds) by applying the locomotive brake.
248. On steep long descents, in trains with a charging pressure of 5.6-5.8 kgf/cm 0.7 kgf/cm 2 above charging pressure (on CKD series locomotives - before charging pressure).
If the train brakes are on the mountain mode and full release is not required, then stepwise release is performed by transferring the train brake handle to the train position until the pressure in the UR increases at each stage of release by at least 0.3 kgf / cm 2.
When the pressure in the TM is 0.4 kgf/cm 2 below the pre-brake charge pressure, only fully release the brakes.
249. On locomotives of the CKD series, in order to apply service braking, it is necessary to transfer the JZ-7 train brake handle from the train position to the brake position (handle positions from III to V) to reduce the pressure in the UR from the set charging pressure by the required value. Perform the first stage of braking by reducing the pressure in the SD: in empty trains - by 0.5-0.6 kgf / cm 2, in loaded trains - by 0.6-0.7 kgf / cm 2, on steep long descents - by 0.7-0.9 kgf / cm 2, depending on the steepness of the descent.
On a flat track profile with slopes up to 0.008 ‰, when following the green light of a traffic light or along a free stretch, the first stage of braking is allowed (except for checking the operation of automatic brakes) 0.5 kgf / cm2 with the release of air from the TM. The second stage, if necessary, should be performed after at least 5 seconds.
250. In a moving train with a length of up to 100 axles, it is allowed to turn on the traction on the locomotive no earlier than 30 seconds after the train brake handle has been moved to the release position.
In a moving train with a length of more than 100 axles, it is allowed to turn on the traction on the locomotive no earlier than after the time specified in the VU-45 certificate, which is necessary to release the brakes of the tail car.
251. After stopping the train with the use of automatic brakes, it is necessary to wait for the time from the moment the train brake handle is moved to the release position until the locomotive is set in motion:
after the stage, if the flat mode is turned on on the air distributors - at least 1.5 minutes, the mountain mode - at least 2 minutes;
after full service braking, if the flat mode is switched on on the air distributors - at least 2 minutes, the mountain mode - at least 3.5 minutes;
after emergency braking in trains with a length of up to 100 axles, if the flat mode is turned on on the air distributors - at least 4 minutes, the mountain mode - at least 6 minutes;
after emergency braking in trains with a length of more than 100 axles, if the flat mode is turned on on the air distributors - at least 6 minutes, the mountain mode - at least 9 minutes.
In January 2007, on the South-Western Road (Ukraine), an automatic coupler broke in the middle part of a freight train weighing 5.2 thousand tons and 56 cars long, which was driven by an electric locomotive VL80T. The marriage was allowed on a steep section with a critical path profile (ascent - a small platform - descent) at the moment the brakes were released, when, after discharging the brake line (TM) by 0.7 kgf / cm 2, the speed decreased from 58 to 40 km / h.
In the composition, as it was later found out, the brakes in six cars did not work, five of which were in its head part, and the tail part contained eight loaded tanks. On the overhanging profile, the brakes at the head of the train were released much earlier than at the tail, so the head cars, already on the descent, rolled forward. At the same time, the tail section was still on the site in a braked state.
Additionally, at the moment of jerking the head of the train forward, its rupture was facilitated by the weight of the tanks, the brakes of which, moreover, had not yet been released (the break occurred at the 25th second after the start of setting the driver’s crane handle to the released position with the actual release of the tail cars in 44 s) . Traces of old cracks with an area of up to 9% of the entire section were visible on the shank of a broken coupler. The driver should, when releasing the auto-brakes with the auxiliary brake valve No. 254, keep the electric locomotive in the inhibited state until the release process in the train is completed.
Could the driver know when the brakes on the train would be released so that later the auxiliary brake of the locomotive would be released in steps? Of course, before that there was enough time and braking (the last before the cliff was the fifth from the beginning of the movement). After all, the driver, checking the effectiveness of the automatic brakes along the route (along the distance traveled and the speed drop by 10 km / h), must also evaluate how they behave during the vacation period. If, having carried it out with the driver’s crane, the speed of the train stopped decreasing (stabilized) or began to increase (on the descent), then we can tentatively assume that the autobrakes have already been released. Usually this time is 40-100 s.
Now let's consider what requirements for the release of brakes in a freight train are imposed by instructions No. TsT-TsV-TsL-VNIIZhT / 277 in the system of Russian Railways and No. TsT-TsV-TsL / 0015 - roads of Ukraine. The braking time by a step of 1.5 - 2.0 kgf / cm 2 by crane No. 254 during the release of automatic brakes in the train, the first instruction sets 30 - 40 s, the second - 40 - 60 s, and then the locomotive brake must be released in steps. Moreover, the instruction No. TsT-TsV-TsL / 0015 indicates the condition that the handle of the crane No. 254 should be finally set to the released position only after the complete release of the autobrakes in the composition, including in its tail section.
But, as a rule, in winter, vacation for all freight trains exceeds the time set by the instructions. The same applies to any time of the year when following trains that contain tanks and hopper-dispensers of all modifications, and also have an increased length. The release of the brakes in trains takes much longer than for the 30 - 40 (40 - 60) s established by the instructions. If, after this time, the brake of the locomotive is released, the previously compressed train will begin to "shoot". When a freight train is moving downhill, when the brakes of the wagons in its tail section have not yet been released, the breakage of the automatic coupler in the second or third part is guaranteed. How can you be a driver? Undoubtedly, the regulated 30 - 40 (40 - 60) seconds of holding the locomotive brake must be increased to the full release of the automatic brakes in the train. According to the same instructions, the release time of the brakes of the tail cars in a train with a length of more than 200 axles can be 80 s, and at sub-zero temperatures - 120 s. Of course, the driver can be guided by the time indicated in the VU-45 certificate, in accordance with the procedure established for Russian roads (unfortunately, such regulations have not been introduced on the roads of Ukraine). But this time can be put down fictitiously. Therefore, the driver additionally evaluates the duration of the release of the automatic brakes when checking the effectiveness of their action. He must be guided by this time, driving the train in the future.
So, when checking the operation of the brakes, the time of their release is approximately determined from the moment the driver's crane handle is set to the release position until the train speed reduction (stabilization) is clearly stopped. If the vacation time was 60 - 120 s (which corresponds to the instructions), then questions arise: how will the wheelsets of the locomotive behave, will they overheat, will the tires shift when braking by crane No. 254 with the same time? Here, of course, ambient temperature matters. In winter, of course, the probability of overheating of tires decreases and, accordingly, it is possible to increase the continuous time of braking by the auxiliary brake valve.
Although it is known that on a shunting diesel locomotive, where often a reduction in the speed of the train occurs only due to the use of crane No. 254, the time of 30–40 (40–100) s is significantly exceeded, but no shifts of the bandages are observed. Therefore, it is necessary to conduct additional studies (theoretical and practical) in order to finally say what the time of continuous braking by crane No. 254 can be and with what allowable pressure in the TC so that the braking conditions are acceptable for the condition of the wheelset tires.
Here, of course, in addition to the ambient temperature, one should also take into account the diameter of the wheel, the thickness of the tire, the speed of movement, i.e. conditions for the distribution (dissipation) of thermal energy. It is clear that if the locomotive has an electrodynamic brake, these problems are removed. The conditions for braking, releasing and switching on traction are facilitated if the train and on the locomotive have a pressure control device ТМ for the tail car.
On the other hand, regulatory documents allow holding the brakes of a freight train at one braking stage for up to 2.5 minutes (and even longer for two or more stages). Consequently, the brake of the locomotive can also be in such a inhibited state. After all, it is not written anywhere that during the period of operation of automatic brakes in a train, crane No. 254 should be placed on the “buffer”, i.e. release the brake of the locomotive (except when checking the operation of the auto brakes). Also, nowhere is it specified how long it is possible to apply the auxiliary brake (simultaneously with the braking of the train) and then, accordingly, continue to keep it in the inhibited state already during the release of the auto-brakes in the composition.
Probably, if the auxiliary brake of the locomotive was not applied during the period of braking by the train, then the duration of its application, even when the automatic brakes of the train are released, may exceed the established 30 - 40 (40 - 60) s. Therefore, in the Instruction for the operation of road brakes of Ukraine No. TsT-TsV-TsL / 0015, the holding time of the locomotive in a braked state with a pressure in the brake cylinder of 1.5 - 2.0 kgf / cm 2 when releasing the automatic brakes of a freight train up to 350 axles is increased from 30 - 40 to 40 - 60 s. But after that, the locomotive brake is released in stages so that its complete release by crane No. 254 does not precede the time for the complete release of the train brakes. An exception can be made only in cases where the train is on the platform or rise.
The use of position II of the driver's crane handle for releasing the automatic brakes makes it possible to somewhat slow down this process and thereby keep the train in a compressed state (without leaving its head part forward), using the pressure in the TC that is permissible for such cases up to 2.0 kgf / cm 2. After the gradual release of the autobrakes, the longitudinal dynamic responses will also not change rapidly. And in the future, the position I of the driver's crane will ensure a reliable release of the tail section of the train. That is, when following the descent of an increased mass, it is better to release the brakes in the above way, and of normal or increased length, as well as containing tanks and wagons of a hopper-dosing type (with delayed release), to accelerate the release, apply position IV of the driver's crane.
Of course, it is difficult to keep a train of increased mass, which follows the descent, in a compressed state during the release of automatic brakes, using only crane No. 254. It is necessary to increase the pressure in the shopping center to 2.5 - 4.0 kgf / cm 2 or keep the valve in a slow state for a long time. Therefore, in the newly issued instruction No. TsT / 0150 on the roads of Ukraine on preventing the breakage of automatic couplers, it is allowed for the driver to release the brakes on the slopes by setting the crane handle for 20 - 30 s to position II. Then position I, according to the requirements of the instructions for the brakes, set the pressure in the TM to 0.5 - 0.7 kgf / cm 2 above the charging one. In the process of release, valve No. 254 remains in the brake position with the pressure in the TC maintained from 1.5 to 2.5 kgf / cm 2. Or at the same time use an electric brake (if available).
Knowing the approximate release time of the automatic brakes, the driver can control the train with less risk of breaking the automatic coupler. Consider several options for the operation of autobrakes.
First option: the brake release time is too high. This symptom is already determined when checking the operation of the brakes - the speed of the train, even after setting the driver's crane handle to the release position, continues to fall. Such differences can be from the speed of the beginning of the brake test of 40 - 60 km / h to its decrease within 10 - 30 km / h, i.e. the speed is reduced by 20 - 40 km/h. This phenomenon is especially often observed in trains that include hopper-dosing-type cars and tanks.
If the release of automatic brakes is carried out slowly, then the driver, when further following, in order to speed up this process, must use position IV, i.e. leave to carry out position I, setting the pressure in the surge tank (UR) higher than the charging one by 0.5 - 1 kgf / cm 2, depending on the length of the composition and the actual density of the TM. Then the crane handle should be transferred from position I to IV and after 30 - 40 s, after briefly moving the handle to position I, install it in the train.
With this very effective method of improving the release of automatic brakes, it is necessary to be sure that the density of the UR and the equalizing piston (UP) in position IV is sufficiently high and meets the established standards (a pressure decrease of 0.1 kgf / cm 2 occurs in at least 3 minutes). In the case of a low density of UR and UE, the release of autobrakes using position IV becomes impossible, since there is a high probability of their operation.
Second option operation of automatic brakes: when checking their action and further driving the train, it was determined that during braking and release, significant longitudinal dynamic forces are observed (rollback of the head section, incursion of the tail section, etc.). In this case, when following the descent and the need to reduce speed, use the VA position of the driver's crane. First, the brake line is discharged by 0.3 - 0.5 kgf / cm 2 with the V position, and then with the VA position until the pressure drops by the required amount.
The use of such braking (V -VA), instead of only one stage by reducing the pressure by 0.8 - 1.2 kgf / cm 2, as suggested by engineer N.K. Vasin in the article “Why automatic couplers break in freight trains” (see Lokomotiv No. 12, 2006), can reduce the effort in the train during braking and, in addition, practically eliminate the overpressure in the UR at position IV of the driver’s valve and a large discharging TM.
When downhill is a heavy train with significant reactions, quickly releasing the auto brakes can increase the forces on the auto couplers. Therefore, in these cases, it is not worth using position IV of the driver’s crane for release. From the experience of driving trains, it is recommended to gradually release the brakes by putting the driver's crane handle in the train position for 20 - 30 s, and then release the brakes in position I, setting the pressure in the TM by 0.5 - 0.7 kgf / cm 2 above the charging one. In this case, during the release of the brakes in the train, crane No. 254 remains in the inhibited position, maintaining the pressure in the TC from 1.5 to 2.5 kgf / cm 2, or an electric brake is used. When investigating cases of breakage of automatic couplers, it is necessary to carefully conduct a control check of the brakes, to find out the reasons that influenced the occurrence of reactions in the train. Here it is important to check the release time of the brakes of the tail cars (and not just the last one), the density of the TM in positions II and IV of the driver’s crane, the pressure of the TM in the tail section of the train, the presence of disconnected, failed or spontaneously released brakes in the group of cars. Especially such shortcomings in the head of the train during vacation can lead to its rollback when following the descent and, as a result, to a break in the automatic coupler.
Those members of the commission who check the operation of the automatic brakes separately for the head and tail parts of the train act unskilled. It is important when investigating on a speedometer tape (a magnetic carrier of an electronic speedometer or ALS-Mu, CLUB) to make sure that the brakes are applied correctly, depending on the track profile. It should be noted that during the investigation, they “forget” to analyze how this train (if it was transit) was driven by previous drivers.
Already during the maintenance of the freight train by these drivers, the longitudinal-dynamic forces in it could give rise to the appearance of a crack in one of the automatic couplers. Later, under certain conditions, it developed to a complete breakage of the coupling device. Moreover, because of the short time, the crack did not have time to darken (oxidation of the metal and darkening of the fracture site occur within two to five days, depending on weather conditions). That is, the commission that investigates the case of a break may mistakenly consider a “fresh” break only as the fault of the last driver.
In conclusion, it should be noted that the use of only crane No. 254 instead of braking a train consisting of empty cars located in its head part can lead to unacceptable compressive forces in case of deviations from the norms for the maintenance of rolling stock and rail track. As a result, the empty car will be squeezed out and come off. In order to be able to correctly analyze the procedure for applying the auxiliary brake valve, it is necessary to provide for the recording of its operation on a magnetic medium (movement parameter recorder) in electronic systems.
9.1.18. For all types of service braking with automatic brakes, reduce the pressure in the surge tank by the driver’s crane from the set charging pressure by at least the first stage value set for all passenger and freight trains in accordance with clauses 9.2.1.1, 9.3.1 of these Rules. In case of stepwise braking, the subsequent stages of braking should be performed by reducing the pressure in the surge tank in the range from 0.3 to 0.8 kgf/cm2, depending on the need. When the train moves to the planned stop, start braking with the first stage, after reducing the speed by 25-50% of the initial one, if necessary, increase the braking.
The best train braking smoothness is ensured by the discharge of the brake line at the beginning of service braking by the value of the first stage.
9.1.19. When braking from a speed of 40 km/h or less in trains with 50% or more cars equipped with composite brake pads or disc brakes, the brakes must be actuated somewhat earlier than with cast-iron brake pads.
9.1.20. When performing full service braking in one step, reduce the pressure in the surge tank by 1.5 - 1.7 kgf / cm2. This type of braking should be used in exceptional cases when it is necessary to stop the train or reduce its speed at a shorter distance than when performing stepped braking.
9.1.21. Emergency braking in all trains and on any track profile should be used only when an immediate stop of the train is required. It is carried out by the driver's crane, and, if necessary, by a combined crane from the leading or driven (with double or multiple traction) locomotives. After moving the handle of the driver's crane or the combined crane to the emergency braking position, activate the sandbox and the auxiliary brake of the locomotive and turn off the traction, leave the handle of the driver's crane or the combined crane in the emergency braking position, and the auxiliary brake handle - in the extreme braking position until it stops completely.
9.1.22. In order to avoid a sharp deceleration of the movement of the locomotive when the auxiliary brake valve is used and the occurrence of large longitudinal-dynamic reactions in the train at speeds of 50 km / h or less, it is necessary to brake with this crane when driving the train in steps, except in the event of an emergency stop.
When actuating the auxiliary brake of passenger and freight locomotives (except for shunting locomotives), avoid systematic effective braking with an increase in pressure in the brake cylinder at one time to more than 1.5 kgf/cm2. As a rule, service braking with an auxiliary brake with a pressure of more than 1.5 kgf/cm2 in the brake cylinders of the locomotive with ridge brake shoes should be repeated in a second step after holding the pressure in the cylinders up to 1.5 kgf/cm2 for 30-40 s.
It is prohibited to use the auxiliary brake to prevent the locomotive from slipping.
9.1.23. The auxiliary brake of the locomotive, if used, should be released after the autobrakes of the train have been released.
9.1.24. Before braking by reducing the pressure in the surge tank by more than 1.0 kgf/cm2 with automatic brakes or with pressure in the brake cylinders of locomotives over 2.5 kgf/cm2 with electro-pneumatic brakes, first activate the sandbox.
9.1.25. When stopping braking using sand on a locomotive, stop the sand supply at a speed of 10 km/h before stopping. If a single following locomotive is stopped with sand in a section with automatic blocking or in a station equipped with electrical interlocking, then it is necessary to set the locomotive in motion and move onto clean rails.
9.1.26. When approaching the station, prohibition signals and speed reduction signals, it is necessary to activate the automatic brakes in advance and reduce the speed of the train so as to prevent the passage of the established stopping place at the station, the prohibition signal, the limit post, and the speed reduction signal and the speed limit place should proceed at speed set for this location. The speed of movement should not exceed 20 km / h at a distance of at least
400 - 500 m to the prohibition signal.
When approaching a prohibition signal or a limit post, the full release of the brakes should be made only after the train has stopped.
9.1.27. If, after the release of the automatic brakes, it becomes necessary to re-brake, this release, both in passenger and freight trains, should be carried out in advance at such a speed as to ensure the necessary charging of the brakes for repeated braking.
9.1.28. In order to avoid a train rupture or the occurrence of large longitudinal-dynamic reactions in it, when starting from a stop after a stop using automatic brakes, it is allowed to set the locomotive in motion only after all automatic brakes in the train are released.
9.1.29. When hitching two or more operating locomotives to the train, the driver of the first locomotive controls the brakes in the train.
9.1.30. The control of auto brakes of a raft of inactive locomotives and multiple unit rolling stock shall be carried out in the manner established by these Rules for the corresponding type of train with locomotive traction.
9.1.31. Trains with locomotives equipped with an electric brake must be operated with the obligatory use of this brake. Braking modes and places for applying electric brakes are set in local instructions and mode maps of the infrastructure owner, which are developed on the basis of calculations, the results of experimental trips and taking into account the requirements of the factory operating instructions for this series of locomotives. At the same time, the braking force should not exceed the maximum allowable value in terms of the stability of the rolling stock in the track, in terms of its strength and impact on the track.
9.1.32. To ensure the set speed of movement (20 km/h), when approaching prohibition signals and train stop signals, it is necessary to apply braking by automatic brakes, and in passenger trains - by electro-pneumatic ones in accordance with clauses 9.1.26, 9.2.1, 9.2.2 of these Rules.
9.1.33. In a freight-passenger train, if there are no freight cars in its composition, the brakes are serviced and controlled as in a passenger train.
9.1.34. Each stop of a freight train, a single following locomotive, should be carried out using automatic brakes.
9.2 Brake control in passenger trains.
9.2.1. Control of auto brakes by cranes of the driver No. 000, 394, 395.
9.2.1.1. For service braking en route, it is necessary to transfer the driver’s crane handle from train to position V and reduce the pressure in the surge tank from the set charging pressure at the first stage by 0.3–0.5 kgf/cm2, regardless of the train length.
When the required pressure in the surge tank is reached, move the driver's valve handle to position IV (shut off with mains supply). If necessary, the next stage of braking can be performed only after the release of air from the line through the driver's valve is completed.
When approaching prohibitory signals and stopping at stations, after stopping the release of air from the brake line through the driver’s crane, turn his handle to position III (except for trains that include cars with Western European-type automatic brakes with stepped release).
If the train is braked by a step of 0.3 kgf/cm2, then before the start of the holiday, increase the discharge of the brake line to 0.5 kgf/cm2.
9.2.1.2. When approaching signals with a permissive indication and repeated or imprudent braking, when the train can stop earlier than the established or required place, release the autobrakes after each braking by moving the driver’s valve handle to position I until the pressure in the surge tank rises to
5.0 - 5.2 kgf / cm2; then move the crane handle to the train position, and before subsequent braking - to position III.
If, during the release of the automatic brakes, the spare tanks do not have time to recharge to the set pressure, to perform the next (repeated) braking, reduce the pressure in the brake line by at least 0.6 kgf/cm2.
It is allowed, if necessary, in case of imprudent braking to stop, to release the automatic brakes by moving the driver’s crane handle to the train position and, after reaching the required increase or stabilization of the train speed, move the crane handle to position III (shutdown without mains power supply) with the readiness to perform repeated braking to stop the train in the required location.
