Series code sending centralized track circuit system

Abstract

The invention provides a series code sending centralized track circuit system, and belongs to the technical field of track traffic. A primary side of a first choking unit in the series code sending centralized track circuit system is used for being connected with a steel rail, a secondary side of the first choking unit is connected with an outdoor power transmission end of an indoor sending unit, and a first end of the indoor sending unit is used for being connected with an output end of a coding transmitter. The second end of the indoor transmitting unit is used for being connected with a track circuit power source, the primary side of the second choke unit is used for being connected with a steel rail, the secondary side of the second choke unit is connected with the outdoor power receiving end of the indoor receiving unit, and the first end of the indoor receiving unit is used for being connected with the output end of a coding transmitter. The second end of the indoor receiving unit is used for driving the track relay. According to the track circuit system, simplification, centralization and high reliability of the track circuit system can be achieved, and the maintenance cost is reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of rail transit technology, and in particular to a serial code-generating centralized rail circuit system. Background Art

[0002] The railway track circuit system is a general term for commanding and controlling train operation, providing train location information, transmitting command information to trains, and integrating various control equipment. The 25Hz AC phase-sensitive track circuit (hereinafter referred to as: 25Hz track circuit) is a station track circuit technology used in conjunction with electrified railways. The rails in the 25Hz track circuit are both the return channel for the 50Hz traction current of the electric locomotive and the channel for the 25Hz track circuit. In order to ensure that the track circuit is free from interference from the traction current, a choke transformer is used to achieve double-circuit electrical isolation, and the frequency difference between the 25Hz track circuit and the 50Hz electrified traction current is used to distinguish the nature of the electrical signal transmitted in the rails, thereby realizing that the traction current and the track circuit current share the rail channel. With the continuous increase in train speed, in order to more safely control the operation of the train, the 25Hz track circuit has been added with a frequency-shifted coded information function to send the locomotive to control the train speed.

[0003] Due to the continuous expansion of the functions of the 25Hz track circuit, coupled with high-speed and heavy-load trains, the actual traction (return) current exceeds 1000A, which makes the electrical isolation effect of the choke transformer continue to decline, reducing the anti-interference ability of the track circuit; secondly, various electrical equipment and instruments added to expand the functions not only reduce the reliability of the track circuit system, but also increase the workload of on-site maintenance personnel. Summary of the invention

[0004] The disclosed embodiment provides a serial code-generating centralized track circuit system to achieve simplicity, centralization and high reliability of the track circuit system and reduce maintenance costs.

[0005] The embodiment of the present disclosure provides a series code-generating centralized track circuit system, comprising a first choke unit, a second choke unit, an indoor transmitting unit and an indoor receiving unit. The primary side of the first choke unit is used to connect to the rail, the secondary side of the first choke unit is connected to the outdoor power supply end of the indoor sending unit, the first end of the indoor sending unit is used to connect to the output end of the electric coding transmitter, and the second end of the indoor sending unit is used to connect to the track circuit power supply. The primary side of the second choke unit is used to connect to the rail, the secondary side of the second choke unit is connected to the outdoor power receiving end of the indoor receiving unit, the first end of the indoor receiving unit is used to connect to the output end of the electric coding transmitter, and the second end of the indoor receiving unit is used to drive the track relay; The first choke unit and the second choke unit are both choke transformer signal coils.

[0006] In an exemplary embodiment of the present disclosure, a traction interference absorption protection box is provided on the secondary side of the first choke unit, and an access point of the traction interference absorption protection box is connected in parallel with the track power transmission circuit.

[0007] In an exemplary embodiment of the present disclosure, the indoor transmitting unit includes a transmitting track voltage adjustment transformer, a capacitor C11, a first coded transmitting transformer and a capacitor C12. The primary side of the first electro-encoded transmission transformer is used to connect to the output end of the electro-encoded transmitter, the secondary side of the first electro-encoded transmission transformer is connected in series to the track circuit power transmission loop, and the signal output by the secondary side of the first electro-encoded transmission transformer is output to the outdoor power transmission end through capacitors C11 and C12; The primary side of the transmitting track voltage regulating transformer is used to connect to the track circuit power supply, and the secondary side signal of the transmitting track voltage regulating transformer is output to the outdoor power transmission end through capacitor C11, capacitor C12 and the secondary side coil of the first coded transmitting transformer.

[0008] In an exemplary embodiment of the present disclosure, a capacitor C13 is connected in series to the primary side of the first coded transmitting transformer.

[0009] In an exemplary embodiment of the present disclosure, the indoor receiving unit includes a capacitor C21, a second electronically coded transmitting transformer, a capacitor C23 and a cable simulation resistor RX. The primary side of the second electric code transmission transformer is used to connect to the output end of the electric code transmitter, and the secondary side of the second electric code transmission transformer is connected in series to the track circuit receiving circuit. The signal output by the secondary side of the second electric code transmission transformer is output to the outdoor receiving end through the capacitor C21; The track voltage received by the outdoor power receiving end drives the track relay through the secondary side coil of the second coded transmitting transformer, the capacitor C23 and the cable simulation resistor RX.

[0010] In an exemplary embodiment of the present disclosure, the series-coded centralized track circuit system further includes a candidate compensation capacitor and a switching switch. The switching switch is used to switch the secondary side coil of the second coded transmitting transformer to be connected with the capacitor C23 or the candidate compensation capacitor.

[0011] In an exemplary embodiment of the present disclosure, a capacitor C24 is connected in series to the primary side of the second coded transmitting transformer.

[0012] In an exemplary embodiment of the present disclosure, the transformation ratio of the signal loop of the choke transformer is 1:40.

[0013] The beneficial effects of the serial code-generating centralized track circuit system provided by the embodiment of the present disclosure are as follows: In the disclosed embodiment, the primary sides of the first choke unit and the second choke unit are connected to the rails, and can obtain signals and currents on the rails. The secondary sides are respectively connected to the outdoor power transmission end of the indoor transmitting unit and the outdoor power receiving end of the indoor receiving unit, so that the traction current, track circuit current and coded information share the rail channel.

[0014] Among them, this embodiment cancels the track transformer. At the same time, because the attenuation of the track transformer to the 2000Hz electro-coded frequency shift is eliminated, the electro-coding and track circuit loops are completely merged, which not only reduces the taps of the choke transformer signal loop, but also cancels the electro-coded isolation inductor and 25Hz isolation capacitor. The choke unit circuit is simpler and has fewer components, thereby realizing the simplification, centralization and high reliability of the track circuit system and reducing maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 It is a diagram of the traction return current path in the traditional track circuit system; Figure 2 It is a track circuit loop current path diagram in a traditional track circuit system; Figure 3 It is the parallel transmission and isolation principle diagram of the indoor transmission unit in the traditional track circuit system; Figure 4 It is the schematic diagram of parallel transmission and isolation of indoor receiving units in the traditional track circuit system; Figure 5 It is a schematic diagram of a serial code-generating centralized track circuit system provided by an embodiment of the present disclosure; Figure 6 yes Figure 5 The serial code transmission current path diagram of the sending unit in the middle room; Figure 7 yes Figure 5 The serial code current path diagram of the receiving unit in the middle room; In the figure: 1-rail, 2-outdoor power transmission end, 3-outdoor power receiving end, 4-track relay, 5-first choke unit, 6-second choke unit, 7-indoor sending unit, 8-indoor receiving unit, 9-first coded sending transformer, 10-second coded sending transformer, 11-transmitting track voltage adjustment transformer. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the present solution, the technical solution in the embodiments of the present solution will be clearly described below in conjunction with the drawings in the embodiments of the present solution. Obviously, the described embodiments are embodiments of a part of the present solution, not all embodiments. Based on the embodiments in the present solution, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present solution.

[0018] The term "including" and any other variations in the specification and claims of this solution and the above drawings mean "including but not limited to", and are intended to cover non-exclusive inclusions and are not limited to the examples listed in the text. In addition, the terms "second" and "second" are used to distinguish different objects, not to describe a specific order.

[0019] In the traditional track circuit system, each 25Hz track circuit section is composed of an indoor isolation box at the power transmission end, an outdoor trackside XB box and a track transformer inside the box, an outdoor isolation box, a current-limiting resistor, a choke transformer and a rail lead-in wire, a rail lead-in wire at the power receiving end, a choke transformer, a trackside XB box and a current-limiting resistor inside the box, a track transformer, an outdoor isolation box, and an indoor isolation box, a protective box, and a binary two-position relay at the indoor power receiving end.

[0020] There are three current loops in the 25Hz track circuit: traction current loop, track circuit loop, and coding loop. The working principles of each loop are introduced below: (1) Traction current circuit like Figure 1 As shown in the figure, the current output from the traction substation of the electric locomotive is connected to the locomotive through the overhead contact network, and then returns to the traction substation through the two rails 1 after passing through the locomotive traction motor. The current returning from the rails 1 to the substation is called traction return current. When the two rails 1 are normal, the return currents of the two rails 1 are in the same direction and equal in magnitude; when the currents of the two rails 1 flow into the terminals 1 and 2 of the choke transformer respectively and flow out from the middle tap 3, since the current directions of the choke transformers 1-3 and 2-3 are opposite, a directional variable magnetic field cannot be generated, so there is no 50Hz traction current induction output on the secondary side of the choke transformer, thereby realizing the 50Hz traction current loop and the 25Hz track circuit loop.

[0021] (2) Track circuit loop The 25Hz track circuit power supply is output by the track transformer at the power transmission end, enters the secondary side of the choke transformer at the power transmission end, induces the output track surface voltage between the terminals 1-2 on the primary side of the choke transformer, and is sent to the two rails 1 through the lead wires; at the power receiving end of the track circuit, the track surface voltage of the two rails 1 enters the terminals 1-2 on the primary side of the choke transformer at the power receiving end respectively. Since the current directions of the two coils 1-3 and 3-2 are the same, the track voltage is induced and output on the secondary side of the choke transformer at the power receiving end. After passing through the track transformer at the power receiving end, the track relay 4 is driven to be sucked up, indicating that there is no train occupying the track section; when the train is occupied, the train wheelset short-circuits the track surface voltage of the two rails 1, the power receiving end cannot receive the track surface voltage, and the track relay 4 falls, indicating that there is a train occupying the track section.

[0022] (3) Coding circuit Track circuit coding, that is, sending frequency-shifted electrical signals with a center frequency of 1700Hz-2600Hz containing train speed control information to two rails 1 through the power transmission and receiving end track transformers and choke transformers indoors. The frequency-shifted signals are superimposed on the 25Hz track circuit loop in parallel. In order to avoid mutual interference and absorption of electrical signals from two different loops, indoor and outdoor isolation devices are set up in the 25Hz track circuit loop. Figure 3 L+C1 in the figure is the electronic coding interference blocking element, and C3 blocks the 25Hz track circuit signal from entering the electronic coding element: Figure 4 L2 in the figure is the electronic coding interference blocking element, and C4 blocks the 25Hz track circuit signal from entering the electronic coding element to ensure the normal transmission of the corresponding loop signal.

[0023] The following is a detailed description of the implementation of the present disclosure in conjunction with the specific drawings: This embodiment is based on the actual existing application needs of the 25Hz track circuit, comprehensively considers the anti-interference problem under the large traction return state, the effective superposition of electric coding, the reduction of phase shift, the reduction of outdoor trackside equipment and other factors, breaks through the original technical structure of the 25Hz track circuit system, simplifies the 25Hz track circuit system, and realizes the goals of simplification, centralization, high reliability and low maintenance of the track circuit system.

[0024] Specifically, Figure 5 As shown, the serial code-generating centralized track circuit system of this embodiment includes a first choke unit 5, a second choke unit 6, an indoor transmitting unit 7 and an indoor receiving unit 8. The primary side of the first choke unit 5 is used to connect to the rail 1, the secondary side of the first choke unit 5 is connected to the outdoor power supply end 2 of the indoor sending unit 7, the first end of the indoor sending unit 7 is used to connect to the output end of the electric coding transmitter, and the second end of the indoor sending unit 7 is used to connect to the track circuit power supply. The primary side of the second choke unit 6 is used to connect with the rail 1, the secondary side of the second choke unit 6 is connected with the outdoor power receiving end 3 of the indoor receiving unit 8, the first end of the indoor receiving unit 8 is used to connect with the output end of the electric coding transmitter, and the second end of the indoor receiving unit 8 is used to drive the track relay 4; The first choke unit 5 and the second choke unit 6 are both choke transformer signal coils.

[0025] In this embodiment, the primary sides of the first choke unit 5 and the second choke unit 6 are connected to the rail 1, and can obtain the signal and current on the rail 1. The secondary sides are respectively connected to the outdoor power transmission end 2 of the indoor receiving unit 8 and the outdoor power receiving end 3 of the indoor sending unit 7, so that the traction current, track circuit current and coded information share the rail 1 channel.

[0026] Among them, the first end of the indoor sending unit 7 is connected to the output end of the coded transmitter, receives and processes the coded information, and outputs it to the outdoor power transmission terminal 2; the second end of the indoor sending unit 7 is connected to the track circuit power supply, and outputs the track circuit power supply to the outdoor power transmission terminal 2.

[0027] The first end of the indoor receiving unit 8 is connected to the output end of the electrocoded transmitter, receives and processes the electrocoded information, and outputs it to the outdoor power receiving terminal 3; the track voltage received by the track surface of the power receiving terminal is output through the second end of the indoor sending unit 7 to drive the track relay 4, so as to realize the mutual compatibility between the electrocoded information of the power receiving terminal and the track circuit loop.

[0028] This embodiment eliminates the track transformer. At the same time, because the attenuation of the track transformer to the 2000Hz coded frequency shift is eliminated, the coding and track circuit loops are completely merged, which not only reduces the taps of the choke transformer signal loop, but also eliminates the coded isolation inductor and 25Hz isolation capacitor. The choke unit circuit is simpler and has fewer components, thereby achieving simplification, centralization and high reliability of the track circuit system and reducing maintenance costs.

[0029] In one embodiment of the present disclosure, a traction interference absorption protection box is provided on the secondary side of the first choke unit 5, and an access point of the traction interference absorption protection box is connected in parallel with the track power transmission circuit.

[0030] In this embodiment, it is considered that in the railway track circuit system, when the traction current passes through the rail 1, if the traction current is unbalanced, it will cause interference to the 25 Hz track circuit loop and the coding loop.

[0031] In order to solve the above problem, a 50Hz traction interference absorption protection box (ie, an outdoor adjustment protection box) is provided on the secondary side of the first choke unit 5 and the secondary side of the second choke unit 6 to absorb and suppress interference signals.

[0032] Furthermore, the access point of the 50Hz traction interference absorption protection box is merged with the track circuit loop access point, which further reduces the reflection impedance of the 50Hz absorption loop to the rail 1 side and improves the ability to resist unbalanced current.

[0033] Similarly, a traction interference absorption protection box is also provided on the secondary side of the second choke unit 6, and the access point of the traction interference absorption protection box is connected in parallel with the track power receiving circuit.

[0034] In one embodiment of the present disclosure, the indoor transmitting unit 7 includes a transmitting track voltage adjustment transformer 11, a capacitor C11, a first coded transmitting transformer 9 and a capacitor C12. The primary side of the first electro-encoding transmission transformer 9 is used to connect to the output end of the electro-encoding transmitter, and the secondary side of the first electro-encoding transmission transformer 9 is connected in series to the track circuit power transmission loop. The signal output from the secondary side of the first electro-encoding transmission transformer 9 is output to the outdoor power transmission terminal 2 via capacitors C11 and C12; The primary side of the transmitting track voltage regulating transformer 11 is used to connect the track circuit power supply, and the secondary side signal of the transmitting track voltage regulating transformer 11 is output to the outdoor power transmission terminal 2 through the capacitor C11, the capacitor C12 and the secondary side coil of the first coded transmitting transformer 9.

[0035] In this embodiment, in the traditional track circuit system, a parallel coding method is usually adopted, that is, the electronic coding loop and the track circuit loop are connected in parallel. In order to avoid mutual interference and influence between the electronic coding loop and the track circuit loop, various isolation inductors, capacitors and other devices need to be set, and the circuit structure is complicated.

[0036] In this embodiment, the electronically coded transmitter adopts a serial coding method, which can eliminate various isolation inductors, capacitors and other devices, simplify the circuit structure and the number of components of the 25Hz track circuit system, so as to reduce the failure rate of the track circuit system and improve the system reliability.

[0037] Among them, at the first end of the indoor transmitting unit 7, the capacitor C11 is an absorption capacitor, which can absorb the interference signal on the secondary side of the first electrocoded transmitting transformer 9. At the same time, considering that the electrocoded frequency shift frequency is only about 2000Hz, which is slightly different from the 25Hz power supply frequency of the track circuit, the inductance of the first electrocoded transmitting transformer 9 is also high, and its 25Hz impedance is also high. If it is directly connected in series to the power transmission circuit of the track circuit, the track circuit loop loss is too large, and the normal operation of the track circuit cannot be guaranteed.

[0038] In order to reduce the loss of the 25Hz track circuit, this embodiment uses the secondary side coil of the first coded transmitting transformer 9 and the capacitor C12 to form a 25Hz series resonant circuit, which can reduce the loss of the first coded transmitting transformer 9 to the track circuit loop, thereby ensuring the normal operation of the track circuit.

[0039] At the second end of the indoor sending unit 7, the 25Hz track circuit signal output by the track voltage adjustment transformer 11 is sent, and the low-resistance characteristics of the 25Hz series resonant circuit composed of the secondary side coil of the first coding sending transformer 9 and the capacitor C12 are utilized to output the track power supply to the outdoors, thereby realizing the mutual compatibility between the coding at the power transmission end and the track circuit loop.

[0040] In one embodiment of the present disclosure, a capacitor C13 is connected in series to the primary side of the first electronically encoded transmitting transformer 9 .

[0041] In this embodiment, the capacitor C13 is a frequency shift isolation capacitor, which allows the coded frequency shift signal to pass smoothly while preventing other unnecessary frequency components from entering the subsequent circuit links.

[0042] In one embodiment of the present disclosure, the indoor receiving unit 8 includes a capacitor C21, a second electronically encoded transmitting transformer 10, a capacitor C23 and a cable simulation resistor RX. The primary side of the second electric code transmission transformer 10 is used to connect to the output end of the electric code transmitter, and the secondary side of the second electric code transmission transformer 10 is connected in series to the track circuit receiving circuit. The signal output by the secondary side of the second electric code transmission transformer 10 is output to the outdoor receiving terminal 3 through the capacitor C21; The track voltage received by the outdoor power receiving terminal 3 drives the track relay 4 through the secondary side coil of the second coded transmitting transformer 10 and the capacitor C23.

[0043] In this embodiment, at the first end of the indoor receiving unit 8, the secondary side of the second coded transmitting transformer 10 is connected in series to the 25Hz track circuit receiving loop, and the signal output from the secondary side of the second coded transmitting transformer 10 is output to the outdoor receiving terminal 3 via the interference absorption capacitor C21.

[0044] At the second end of the indoor receiving unit 8, the track voltage received by the receiving end track surface drives the track relay 4 through a 25Hz series resonant circuit composed of the secondary side coil of the second coding transmitting transformer 10 and the capacitor C23, thereby achieving mutual compatibility between the receiving end coding and the track circuit loop.

[0045] In one embodiment of the present disclosure, the serial code-generating centralized track circuit system further includes a candidate compensation capacitor and a switching switch. The switch is used to switch the secondary coil of the second coded transmission transformer 10 to be connected to the capacitor C23 or the candidate compensation capacitor.

[0046] In this embodiment, there may be multiple candidate compensation capacitors, such as Figure 5The capacitors C24, C25, C26 and C27 in the circuit have different capacitance values. The position of the switching switch can be adjusted according to actual needs to connect the capacitor C23 or the candidate compensation capacitor to the secondary coil of the second coded transmitting transformer 10 to form a resonant circuit with a specified resonant frequency and adjust the phase of the track circuit.

[0047] In this embodiment, considering that the rail 1 in the track circuit presents inductive characteristics to the 25Hz transmission loop, which will affect the phase of the track circuit signal at the receiving end, in order to solve the above problem, this embodiment sets capacitor C23 and multiple candidate compensation capacitors, and the secondary side of the second coded transmission transformer 10 and capacitor C23 or candidate compensation capacitors form a series resonant circuit. When the resonance point is 25Hz, it does not affect the phase of the track circuit. When the resonance point is lower than 25Hz, the resonant circuit is inductive; when the resonance point is higher than 25Hz, it is capacitive. By adjusting the capacity of the resonant capacitor, the resonance point of the resonant circuit is changed, and the impedance properties of the resonant circuit are also changed, thereby compensating for the phase of the track circuit receiving signal.

[0048] In one embodiment of the present disclosure, a capacitor C24 is connected in series to the primary side of the second electronically encoded transmitting transformer 10 .

[0049] In this embodiment, capacitor C24 is a frequency shift isolation capacitor, which allows the coded frequency shift signal to pass smoothly while preventing other unnecessary frequency components from entering the subsequent circuit links.

[0050] In one embodiment of the present disclosure, the transformation ratio of the signal coils of the choke transformers in the first choke unit 5 and the second choke unit 6 is 1:40.

[0051] In this embodiment, a large number of experimental studies by the inventors have shown that setting the transformation ratio of the signal loop of the choke transformer to 1:40 can achieve the best transmission efficiency of the signal in the track circuit.

[0052] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure 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 make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A series code-generating centralized track circuit system, characterized in that: It includes a first choke unit, a second choke unit, an indoor transmitting unit and an indoor receiving unit, The primary side of the first choke unit is used to connect to the rail, the secondary side of the first choke unit is connected to the outdoor power supply end of the indoor sending unit, the first end of the indoor sending unit is used to connect to the output end of the electric coding transmitter, and the second end of the indoor sending unit is used to connect to the track circuit power supply. The primary side of the second choke unit is used to connect to the rail, the secondary side of the second choke unit is connected to the outdoor power receiving end of the indoor receiving unit, the first end of the indoor receiving unit is used to connect to the output end of the electric coding transmitter, and the second end of the indoor receiving unit is used to drive the track relay.

2. The tandem code-generating centralized track circuit system according to claim 1, characterized in that: A traction interference absorption protection box is provided on the secondary side of the first choke unit, and an access point of the traction interference absorption protection box is connected in parallel with the track power transmission circuit.

3. The tandem code-generating centralized track circuit system according to claim 1, characterized in that: The indoor transmission unit includes a transmission track voltage adjustment transformer, a capacitor C11, a first coded transmission transformer and a capacitor C12. The primary side of the first electro-encoded transmission transformer is used to connect to the output end of the electro-encoded transmitter, the secondary side of the first electro-encoded transmission transformer is connected in series to the track circuit power transmission loop, and the signal output by the secondary side of the first electro-encoded transmission transformer is output to the outdoor power transmission end through capacitors C11 and C12; The primary side of the transmitting track voltage regulating transformer is used to connect to the track circuit power supply, and the secondary side signal of the transmitting track voltage regulating transformer is output to the outdoor power transmission end through capacitor C11, capacitor C12 and the secondary side coil of the first coded transmitting transformer.

4. The tandem code-generating centralized track circuit system according to claim 3, characterized in that: A capacitor C13 is connected in series to the primary side of the first coding transmission transformer.

5. The serial code-generating centralized track circuit system according to claim 1, characterized in that: The indoor receiving unit includes a capacitor C21, a second electronically coded transmitting transformer, a capacitor C23 and a cable simulation resistor RX. The primary side of the second electric code transmission transformer is used to connect to the output end of the electric code transmitter, and the secondary side of the second electric code transmission transformer is connected in series to the track circuit receiving circuit. The signal output by the secondary side of the second electric code transmission transformer is output to the outdoor receiving end through the capacitor C21; The track voltage received by the outdoor power receiving end drives the track relay through the secondary side coil of the second coded transmitting transformer, the capacitor C23 and the cable simulation resistor RX.

6. The tandem code-generating centralized track circuit system according to claim 5, characterized in that: Also included are candidate compensation capacitors and switching switches, The switching switch is used to switch the secondary side coil of the second coded transmitting transformer to be connected with the capacitor C23 or the candidate compensation capacitor.

7. The tandem code-generating centralized track circuit system according to claim 5, characterized in that: A capacitor C24 is connected in series to the primary side of the second coding transmission transformer.

8. The serial code-generating centralized track circuit system according to claim 1, characterized in that: The transformation ratio of the signal coils of the choke transformers in the first choke unit and the second choke unit is 1:40.

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