Method for calculating train braking force based on heavy-load combined train pipe pressure fluctuation

Abstract

The invention provides a method for calculating train braking force based on heavy-load combined train pipe pressure fluctuation, and belongs to the technical field of locomotive braking force calculation. The problem that the requirement for exploration and analysis of heavy-load train pipe pressure fluctuation influence factors cannot be met in the current detection and test of a heavy-load train air braking system is solved. Comprising the following steps: calculating the brake cylinder pressure of the vehicle according to pressure air of an auxiliary air cylinder when the vehicle is braked and pressure air filled into a brake cylinder by a train pipe through a local reduction valve in the secondary local reduction process; the step of calculating the braking force of the vehicle comprises the substeps of calculating brake shoe pressure; calculating the friction coefficient of the brake shoe; calculating the braking force of a single brake shoe; calculating the air braking force of the whole heavy haul train; calculating the train pipe pressure reduction r0 when the braking force of the whole heavy-load train is not influenced by the temperature, calculating the train braking force when the braking force of the whole heavy-load train is not influenced by the temperature according to the r0, and calculating the train braking force when the braking force of the whole heavy-load train is influenced by the temperature; the method is applied to train braking force analysis and calculation.

Description

Technical Field

[0001] The invention provides a method for calculating train braking force based on pipe pressure fluctuation of a heavy-load combination train, belonging to the technical field of locomotive braking force calculation. Background Art

[0002] The train's air brake system is the main component for speed regulation and parking. For heavy-load trains, it is the most important control target in the smooth operation and precise control link, and is one of the most important control systems in the train. The control end of the train's air brake system is in the locomotive, mainly the locomotive's brake machine. The locomotive driver controls the pressure of the brake machine's balancing air cylinder through the air brake handle. The balancing air cylinder controls the pressure of the train's brake pipe through the relay valve (or brake valve) module to achieve the control of the braking and relief of the entire train.

[0003] According to the principle of the train air brake system, the braking force generated by the train air brake is determined by the train pipe pressure reduction, and the train pipe pressure reduction is controlled by the locomotive driver through the brake machine. At present, high-power AC transmission locomotives used to pull heavy-load trains use "initial braking" to slow down or stop. During the "initial braking", the locomotive brake machine controls the train pipe exhaust to achieve a pressure reduction of 50kPa, which forms a braking force on the train.

[0004] However, during the operation of heavy-load trains, the pipe pressure will fluctuate, affecting the train braking force. After comprehensive analysis, it is found that the pipe pressure fluctuation phenomenon is relatively concentrated in seasons and locations. The main reason is that the pressure fluctuation is caused by factors such as temperature and air pressure.

[0005] At present, the detection and testing of the air brake system of heavy-load trains mainly detects parameters such as the train pipe pressure reduction, charging and exhaust time, coupler force, derailment coefficient, wheel weight reduction rate, etc. However, it cannot meet the needs of exploring and analyzing the factors affecting the pipe pressure fluctuation of heavy-load trains, nor does it have the function of synchronously analyzing the pipe pressure fluctuation and the abnormal increase in the pressure reduction for the master and slave controls of heavy-load combination trains, and it does not have the function of directly calculating and displaying the impact of pipe pressure fluctuation on the train air braking force. Therefore, it is necessary to monitor the pipe pressure fluctuation of the existing train air brake system in real time to facilitate the analysis of its impact on train braking. Summary of the invention

[0006] In order to solve the above technical problems, the present invention proposes a method for calculating train braking force based on pipe pressure fluctuation of a heavy-load combination train.

[0007] The technical solution adopted by the present invention is: a method for calculating the train braking force based on the pipe pressure fluctuation of a heavy-load combination train, comprising the following steps:

[0008] S1: Calculation of vehicle brake cylinder pressure: The vehicle brake cylinder pressure P is calculated based on the pressure air in the auxiliary air cylinder during vehicle braking and the pressure air in the train pipe that is filled into the brake cylinder through the decompression valve during the secondary decompression process. z ;

[0009] S2: Calculation of vehicle braking force: including:

[0010] Brake shoe pressure calculation: Single brake shoe pressure K = brake cylinder piston rod thrust P × brake ratio × brake transmission efficiency × (1 / n), where n represents the number of brake shoes driven by one brake cylinder;

[0011] Brake shoe friction coefficient ψ calculation: Its expression is: Where v is the train running speed;

[0012] Calculation of the braking force B of a single brake shoe: The expression is: B = n × K × ψ;

[0013] Air braking force of the entire heavy-load train B z Calculation: Its expression is: B z =N×B, where N is the number of vehicles in the entire heavy-load train;

[0014] Calculate the train pipe decompression r0 when the braking force of the entire heavy-load train is not affected by temperature, and calculate the train braking force B when it is not affected by temperature based on r0 z0 , calculate the train braking force B of the entire heavy-load train affected by temperature C =B z -B z0 .

[0015] Furthermore, in step S1, the pressure increase effect of the train pipe and the brake cylinder during the braking process is not considered, and the brake cylinder pressure P after braking is calculated. z1 =(r×V a +P d ×V w ) / (V c +V w ), where P d is the atmospheric pressure; r is the pressure reduction of the auxiliary air cylinder; V a V is the volume of the auxiliary air cylinder; w V is the dead volume of the brake cylinder; c is the effective volume of the brake cylinder;

[0016] Assume that during the train braking process, the pressure added by the train pipe to the brake cylinder through the local reduction valve is Δ j ,but:

[0017] Brake cylinder final pressure P z =Δ j -P d +(r×Va +P d ×V w ) / (V c +V w ).

[0018] Furthermore, the train pipe decompression amount r0=r when the braking force of the entire heavy-load train is not affected by temperature e1 -r e2 -5, where r e1 To balance the air cylinder pressure before decompression braking, r e2 To balance the air cylinder pressure after decompression braking.

[0019] Furthermore, the expression of the brake cylinder piston rod thrust P is:

[0020]

[0021] Where: d z is the brake cylinder diameter.

[0022] Furthermore, the calculated r0 is used instead of the brake cylinder final pressure P z r in the calculation, the train braking force B is calculated when it is not affected by temperature. z0 .

[0023] Furthermore, the pressure of the balancing air cylinder before the decompression braking and the pressure of the balancing air cylinder after the decompression braking are both obtained by real-time monitoring through the balancing air cylinder pressure sensor.

[0024] Furthermore, the atmospheric pressure P d Collected by air pressure sensor.

[0025] Furthermore, the auxiliary air cylinder pressure reduction amount r is calculated by collecting real-time data before and after braking through the train pipe pressure sensor.

[0026] Furthermore, the train running speed v is obtained through a locomotive safety comprehensive monitoring device connected to the train running monitoring device.

[0027] Furthermore, the data of the balancing air cylinder pressure, train pipe pressure, atmospheric pressure, temperature and humidity are acquired through the data acquisition module, and the data of the balancing air cylinder pressure, train pipe pressure, atmospheric pressure, temperature and humidity of the master locomotive and the slave locomotive in the heavy-load combination train are collected simultaneously, and the data acquisition modules on the master locomotive and the slave locomotive are accurately timed through the Beidou timing device.

[0028] The beneficial effects of the present invention compared with the prior art are as follows:

[0029] 1. It has data collection and recording functions, which can meet the monitoring and analysis of the impact of changes in ambient temperature and atmospheric pressure on the train pipe pressure of heavy-load trains;

[0030] 2. It can calculate the impact of changes in ambient temperature and atmospheric pressure on train braking force in real time;

[0031] 3. The data collection method is safe and reliable and does not affect the normal operation of trains and locomotives.

[0032] 4. It has the function of Beidou timing. After synchronous timing, it can meet the analysis of the cause of pipe pressure fluctuation of heavy-load combination trains; through the pressure data recording of the balancing air cylinder and train pipe before and after the locomotive decompression at different positions, it can analyze the influence of inconsistent train pipe pressure calibration on the train pipe pressure fluctuation and decompression amount;

[0033] 5. It is applicable to the monitoring of pipe pressure fluctuations of 20,000-ton heavy-load combined trains and the real-time calculation of the impact of braking force, and is also applicable to the relevant monitoring and calculation of unit heavy-load trains. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described below in conjunction with the accompanying drawings:

[0035] Figure 1 is a flow chart of the method of the present invention;

[0036] Figure 2 This is a schematic diagram of the clock synchronization setting of the master-slave control locomotive data acquisition and recording device of the present invention. DETAILED DESCRIPTION

[0037] like Figure 1 and 2 As shown, the present invention provides a method for calculating the train braking force based on the pipe pressure fluctuation of a heavy-load combined train. By comprehensively considering the changes in the balancing air cylinder pressure when the locomotive is running and the temperature, humidity and air pressure values ​​of the locomotive operating environment, the influencing factors of the train pipe pressure fluctuation are comprehensively analyzed, and the data of the above sensors are collected into a monitoring device, and the train braking force is calculated by a processor module built into the monitoring device; and according to the air braking principle of the combined train, the balancing air cylinder pressure, train pipe pressure, atmospheric pressure, temperature and humidity of the master locomotive and the slave locomotive are collected simultaneously, and the data acquisition modules on the master locomotive and the slave locomotive are accurately timed by the Beidou timing device, and the Beidou clock information is received through the Ethernet or RS485 port to ensure the synchronization of data collection on the master locomotive and the slave locomotive, thereby ensuring the accuracy of the train braking force calculation.

[0038] The step of calculating the train braking force of the present invention comprises:

[0039] S1: Calculation of vehicle brake cylinder pressure: The air braking force of a heavy-duty freight train is determined by the vehicles in the train, and the braking force of each vehicle is directly controlled by the vehicle brake cylinder pressure. According to the working principle of the 120-1 type control valve of the truck brake system, when the vehicle is decompressed, the compressed air in the vehicle brake cylinder includes the compressed air of the auxiliary air cylinder and the compressed air filled into the brake cylinder by the train pipe through the decompression valve during the secondary decompression process. Therefore, the vehicle brake cylinder pressure is determined by the volume ratio of the auxiliary air cylinder and the brake cylinder and the pressure increment formed by the train pipe on the brake cylinder during the secondary decompression process. Before air braking, the total amount of compressed air in the vehicle is the sum of the volumes of the auxiliary air cylinder, the connecting pipeline, and the front end space of the brake cylinder piston. For the convenience of calculation, the pressurization effect of the train pipe and the brake cylinder during the braking process is temporarily not considered (later it is calculated separately by superposition through △J, see formula (3)), and the brake cylinder pressure after braking is calculated using formula (1).

[0040] P a ×V a +P d ×V w =(P a -r)×V a +P z1 (V c +V w )(1);

[0041] Where: P a is the pressure of the auxiliary air cylinder before braking; P d is the atmospheric pressure; P z1 is the brake cylinder pressure, in kPa; r is the pressure reduction of the auxiliary air cylinder, in kPa; V a V is the volume of the auxiliary air cylinder, take 50L; w V is the ineffective volume of the brake cylinder (including the volume inside the rear cover of the brake cylinder and the volume of the brake cylinder pipeline), which is 5.5L; c is the effective volume of the brake cylinder, that is, the piston area of ​​the brake cylinder (305 2 *π / 4) multiplied by the piston stroke (155±5mm), V c =11.3L.

[0042] By transforming the above formula, we can get formula (2):

[0043] P z1 =(r×V a +P d ×V w ) / (V c +V w )(2).

[0044] Consider the impact of the following two factors on the calculation: adjust formula (2) to formula (3):

[0045] ① During the train braking process, the pressure added by the train pipe to the brake cylinder through the local reduction valve is Δ j .

[0046] ② The relationship between ambient atmospheric pressure and atmospheric relative pressure (gauge pressure). Adjust formula (2) to formula (3).

[0047] P z =Δ j -P d +(r×V a +P d ×V w ) / (V c +V w )(3);

[0048] Substitute the determined parameters, where V a =50, V w =5.5, V c =11.3, based on experience, take Δ j =15, we can get formula (4):

[0049] P z =2.9762r-0.6726P d +15(4).

[0050] S2: Calculation of vehicle braking force, including:

[0051] ① Brake shoe pressure calculation:

[0052] Since there is no mixed formation of heavy-load trains, especially 20,000-ton heavy-load trains, all use C80B vehicles. Therefore, in order to improve the calculation accuracy, the actual brake shoe pressure is directly used instead of the converted brake shoe pressure. According to the structure and parameters of the braking force transmission link of the railway freight car braking system, the brake shoe pressure of a single freight car is:

[0053] Brake shoe pressure K = brake cylinder piston rod thrust P × brake ratio × brake transmission efficiency × (1 / 8);

[0054] According to the C80B vehicle structure, one brake cylinder drives eight brake shoes. Therefore, when calculating the pressure of a single brake shoe, 1 / 8 of the total value should be taken.

[0055] The braking ratio of C80B open wagon is 7.3. According to historical data, the transmission efficiency of the brake shoe of the freight car is 0.50 (50%). The single brake shoe pressure of C80B can be calculated by the above formula to obtain formula (5).

[0056] K=P×7.3×0.5×(1 / 8)=0.4563×P(5);

[0057] According to the brake cylinder structure, the calculation method of the brake cylinder piston rod thrust P is formula (6);

[0058]

[0059] Among them, P z is the air pressure in the brake cylinder (kPa), d z is the brake cylinder diameter (m), which is 305. Substituting formula (6) into formula (5) yields formula (7).

[0060] K=0.0333×P z (7).

[0061] ② Calculation of friction coefficient:

[0062] Since there is no mixed formation of heavy-load train vehicles, especially 20,000-ton heavy-load trains, all use C80B vehicles, so the actual friction coefficient is used for calculation. According to the traction calculation rules, C80B vehicles use high-friction synthetic brake shoes, and the brake shoe friction coefficient ψ is related to the brake shoe pressure and the train running speed v, and the calculation method is formula (8).

[0063]

[0064] ③Calculation of braking force B:

[0065] The braking force B of a single vehicle is composed of the braking forces of eight brake shoes. The value of the braking force of each brake shoe is the product of the brake shoe pressure and the friction coefficient, and the calculation method is formula (9).

[0066] B = 8 × K × ψ (9).

[0067] A 20,000-ton heavy-load train is composed of 210 vehicles, so the air braking force of the entire train is B z The calculation method is formula (10).

[0068] B z =210×B(10).

[0069] Therefore, the mathematical calculation formula for the train air braking force is summarized as the following equation group, namely formula (11).

[0070]

[0071] In this mathematical formula, the variable is P d (atmospheric pressure), r (decompression), v (speed), where P dThe (atmospheric pressure) variable is directly collected by the monitoring device through the sensor, the r (pressure reduction) variable is calculated by collecting real-time data before and after braking through the train pipe pressure sensor, and v (speed) is obtained from the RS485 bus data through the locomotive safety comprehensive monitoring device, thereby calculating the braking force of the entire train in real time.

[0072] If the train pipe pressure of a heavy-load train is not affected by temperature, the train pipe pressure reduction r0 is directly related to the pressure reduction of the balancing air cylinder, and the calculation formula is formula (12).

[0073] r0=r e1 -r e2 -5(12).

[0074] r0 is the decompression of the train pipe when it is not affected by temperature, r e1 To balance the air cylinder pressure before decompression braking, r e2 To balance the air cylinder pressure after decompression braking, r e1 、r e2 All are obtained through real-time monitoring using a balanced air cylinder pressure sensor.

[0075] Use r0 instead of r and substitute it into formula (11) to calculate the train braking force B when it is not affected by temperature. z0 , B z With B z0 By subtracting, we can get formula (13), and the result is the value B of the braking force of the entire heavy-load train affected by temperature. C .

[0076] B C =B z -B z0 (13).

[0077] Combining formulas (11), (12), and (13) we can obtain formula (14).

[0078]

[0079] Calculation example:

[0080] According to the monitoring and calculation data of the heavy-load trains on the Daqin Railway, when the temperature does not change and the running speed is 70km / h, the train air is initially braked, the train pipe pressure reduction is 50kPa, and the device automatically calculates the train braking force to be 1998kN. When the train passes through the Jundushan Tunnel, the temperature in the tunnel rises, causing the train pipe pressure to rise abnormally, resulting in a train pipe pressure reduction of 55kPa, and the train braking force is automatically calculated to be 2290kN. The device automatically calculates that the train braking force affected by the pipe pressure fluctuation is 2290kN-1998kN=292kN.

[0081] In addition, the environmental data required for the train braking force calculation in the present invention is collected synchronously with the data of the locomotive braking system. According to the principle of the train air brake system, the braking force generated by the train air brake is determined by the train pipe pressure reduction, and the train pipe pressure reduction is controlled by the locomotive balancing air cylinder. Therefore, the parameters of the heavy-load locomotive braking system are mainly monitored by the air pressure of the brake balancing air cylinder and the train pipe. The present invention monitors the locomotive brake balancing air cylinder and train pipe pressure by using a pressure sensor with an accuracy of 0.5‰. The installation position of the pressure sensor is selected at the corresponding position of the brake unit balancing air cylinder pressure detection hole and the train pipe pressure detection hole.

[0082] After a long period of tracking analysis and data verification, it was found that the stable train pipe pressure is not only affected by internal factors such as changes in the balancing air cylinder pressure, but is also easily affected by external factors such as changes in ambient temperature, resulting in pressure fluctuations. Therefore, while collecting the balancing air cylinder pressure and train pipe pressure of the locomotive braking system, the temperature, humidity and air pressure values ​​of the locomotive operating environment are also collected in real time to comprehensively analyze the factors affecting the train pipe pressure fluctuations, forming a monitoring device with data collection, display, storage and calculation functions. In order to further analyze the impact of train pipe pressure fluctuations on the braking force of heavy-loaded trains, a calculation model is formed through theoretical deduction and implanted into the monitoring device. The air braking force of heavy-loaded trains is calculated in real time based on the collected data, and the braking force deviation caused by the fluctuation is analyzed simultaneously.

[0083] For a 20,000-ton heavy-load combined train, there are two locomotives distributed throughout the train, forming a power distributed marshaling mode. The locomotive at the head is the master locomotive, and the locomotive in the middle is the slave locomotive, which jointly control the traction and braking of the train. According to the air braking principle of the combined train, both the master and slave locomotives control the train pipe pressure, and there are factors that affect mutual disturbance. Therefore, when detecting pipe pressure fluctuations in the combined train, it is necessary to use two sets of monitoring devices to synchronously monitor the two locomotives respectively, and comprehensively analyze whether the train pipe and equalizing air cylinder pressure parameters of the master and slave locomotives are consistent. If the parameters are inconsistent, the recorded data can be used to analyze its impact on the decompression of the entire train and the time required for relief.

[0084] After the locomotive is powered on, the monitoring device broadcasts the locomotive's driving information, including running speed, position, number of trains, etc., through the LKJ93 junction box. The monitoring device is connected to the LKJ93 junction box via the RS485 data bus to collect the position and speed information of the train. The driving record is used to calculate dynamic parameters such as the friction coefficient of the brake shoe, and the driving position is recorded for data statistical analysis. Through statistics, it can be determined at which positions of the train are prone to pipe pressure fluctuations and the magnitude of the fluctuation, which is convenient for formulating targeted measures.

[0085] The monitoring device is mainly composed of a processor module, a power module, a data acquisition module and a sensor. The processor module is used to receive the data output by the data acquisition module, and at the same time receive the data from the RS485 bus, display the collected data in real time, calculate the braking force of the train and the change in the braking force caused by the pipe pressure fluctuation, and record the collected data and the calculation result data; the power module is used to convert the AC220V power supply or DC110V power supply into a stable 12V power supply required by the internal module of the device; the data acquisition module is used to collect the analog data output by the sensor and send the converted digital quantity to the processor module; the sensors include the equalizing air cylinder pressure sensor, the train pipe pressure sensor, the atmospheric pressure monitoring sensor, the temperature and humidity sensor, etc., among which the equalizing air cylinder pressure sensor and the train pipe pressure sensor use a gauge pressure sensor to monitor the parameters of the locomotive braking system; the atmospheric pressure sensor uses an absolute pressure sensor to monitor the atmospheric pressure at the location where the train passes; the temperature and humidity sensor is used to monitor the temperature and humidity at the location where the train passes.

[0086] For unit trains, since there is only one locomotive, only one set of test equipment is needed during the monitoring process. If there are multiple locomotives, multiple monitoring devices are required. For the test of the 20,000-ton heavy-load combination train, since there are two locomotives in the train, two sets of test equipment are required. Before monitoring the 20,000-ton combination train, it is necessary to use the Beidou timing device to synchronize the two sets of monitoring devices to ensure that the clock scales of the two sets of devices are consistent and to ensure the time consistency of the two sets of devices recording the data of the two locomotives. The monitoring device is synchronized using the universal Beidou timing device, and the monitoring device receives Beidou clock information through the Ethernet or RS485 port to ensure the synchronization of the clocks of multiple devices.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating train braking force based on pipe pressure fluctuation of heavy-load combination train, characterized in that: The following steps are involved: S1: Calculation of vehicle brake cylinder pressure: The vehicle brake cylinder pressure P is calculated based on the pressure air in the auxiliary air cylinder during vehicle braking and the pressure air in the train pipe that is filled into the brake cylinder through the decompression valve during the secondary decompression process. z ; S2: Calculation of vehicle braking force: including: Brake shoe pressure calculation: Single brake shoe pressure K = brake cylinder piston rod thrust P × brake ratio × brake transmission efficiency × (1 / n), where n represents the number of brake shoes driven by one brake cylinder; Brake shoe friction coefficient ψ calculation: Its expression is: Where v is the train running speed; Calculation of the braking force B of a single brake shoe: The expression is: B = n × K × ψ; Air braking force of the entire heavy-load train B z Calculation: Its expression is: B z =N×B, where N is the number of vehicles in the entire heavy-load train; Calculate the train pipe decompression r0 when the braking force of the entire heavy-load train is not affected by temperature, and calculate the train braking force B when it is not affected by temperature based on r0 z0 , calculate the train braking force B of the entire heavy-load train affected by temperature C =B z -B z0 .

2. The method for calculating train braking force based on pipe pressure fluctuation of heavy-load combination train according to claim 1, characterized in that: In step S1, the pressure increase effect of the train pipe and the brake cylinder during braking is not considered, and the brake cylinder pressure P after braking is calculated. z1 =(r×V a +P d ×V w ) / (V c +V w ), where P d is the atmospheric pressure; r is the pressure reduction of the auxiliary air cylinder; V a V is the volume of the auxiliary air cylinder; w V is the dead volume of the brake cylinder; c is the effective volume of the brake cylinder; Assume that during the train braking process, the pressure added by the train pipe to the brake cylinder through the local reduction valve is Δ j ,but: Brake cylinder final pressure P z =Δ j -P d +(r×V a +P d ×V w ) / (V c +V w ).

3. The method for calculating train braking force based on pipe pressure fluctuation of heavy-load combination train according to claim 2 is characterized in that: The train pipe decompression when the braking force of the entire heavy-load train is not affected by temperature is r0 = r e1 -r e2 -5, where r e1 To balance the air cylinder pressure before decompression braking, r e2 To balance the air cylinder pressure after decompression braking.

4. The method for calculating train braking force based on pipe pressure fluctuation of heavy-load combination train according to claim 3 is characterized in that: The expression of brake cylinder piston rod thrust P is: Where: d z is the brake cylinder diameter.

5. The method for calculating train braking force based on pipe pressure fluctuation of heavy-load combination train according to claim 3 is characterized in that: Use the calculated r0 instead of the brake cylinder final pressure P z r in the calculation, the train braking force B is calculated when it is not affected by temperature. z0 .

6. The method for calculating train braking force based on pipe pressure fluctuation of heavy-load combination train according to claim 3 is characterized in that: The pressure of the balancing air cylinder before decompression braking and the pressure of the balancing air cylinder after decompression braking are both obtained by real-time monitoring through the balancing air cylinder pressure sensor.

7. The method for calculating train braking force based on pipe pressure fluctuation of heavy-load combination train according to claim 2, characterized in that: Atmospheric pressure P d Collected by air pressure sensor.

8. The method for calculating train braking force based on pipe pressure fluctuation of heavy-load combination train according to claim 2 is characterized in that: The decompression amount r of the auxiliary air cylinder is calculated by collecting real-time data before and after braking through the train pipe pressure sensor.

9. The method for calculating train braking force based on pipe pressure fluctuation of heavy-load combination train according to claim 1, characterized in that: The train running speed v is obtained through the locomotive safety comprehensive monitoring device connected to the train running monitoring device.

10. The method for calculating train braking force based on pipe pressure fluctuation of heavy-load combination train according to claim 1, characterized in that: The data of balancing air cylinder pressure, train pipe pressure, atmospheric pressure, temperature and humidity are acquired through the data acquisition module. The data of balancing air cylinder pressure, train pipe pressure, atmospheric pressure, temperature and humidity of the master locomotive and the slave locomotive in the heavy-load combination train are collected simultaneously, and the data acquisition modules on the master locomotive and the slave locomotive are accurately timed through the Beidou timing device.

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