GB2621327A

GB2621327A - Rail network management system, and train for operation on a rail network

Info

Publication number: GB2621327A
Application number: GB2211375.7A
Authority: GB
Inventors: ishikawa Shinichiro
Original assignee: Hitachi Rail Ltd
Current assignee: Hitachi Rail Ltd
Priority date: 2022-08-04
Filing date: 2022-08-04
Publication date: 2024-02-14
Also published as: GB202211375D0

Abstract

A system for managing movements of trains 1 on a rail network has trackside communications devices in communication with a central control centre 3. The trackside communications devices wirelessly receive sensor information from on-board train control systems and communicate it to the control centre. The sensor information measures performance parameters (e.g. train speed) and/or external environmental conditions (e.g. weather conditions or leaf fall) of the trains. Based thereon, the control centre identifies network sections where trains may experience wheel slip or slide; determines respective operational requirements for running trains through the identified sections without slip or slide; and communicates the identified sections and operational requirements to on-board train control systems via the trackside communications devices. The operational requirements may include maximum speed limits or commands to operate sandboxes or air blowers 5 (e.g. for gritting or removing leaves or moisture from rails) or switch from axle train speed sensors 2 to radar train speed sensors 4 while running through the identified sections.

Description

RAIL NETWORK MANAGEMENT SYSTEM, AND TRAIN FOR OPERATION ON A RAIL NETWORK

Field of the Invention

The present invention relates to a rail network management system and a train for operation on a rail network.

Background

When rails of a rail network become moist due to bad weather, or when fallen leaves accumulate on the rails, the coefficient of friction between the rails and the wheels of trains running on the rails decreases. This can cause sliding on train decelerations and slipping on train accelerations, and for several reasons punctual train operation can be affected.

Firstly, sliding increases braking distance such that it becomes necessary to reduce operating speeds for safe train operation. In practical terms, maximum speed limitations on train movements may be imposed across wide regions of the network, leading to delays and timetable disruption.

Secondly, slipping can cause problems for axle speed sensors which measure train speed by measuring rotational speeds of wheels or axles of the train. For example, slipping can lead to poor calculation of train position (by overestimation of distance travelled). As a result, network operating densities may be decreased to increase minimum distances between trains, again leading to delays and timetable disruption.

Thirdly, most trains have multiple sensors from which speed and/or position measurements are derived, e.g. plural axle speed sensors on different axles of the train. These multiple sensors provide useful redundancy in case of sensor failure. However, under conditions causing sliding or slipping, different sensors may provide different readings due to different degrees of sliding or slipping at the different sensors. For example, wheels at the front of a train tend to be more susceptible to sliding and slipping than wheels further back, and thus axle speed sensors at the front of a train may provide different readings to those further back. Thus even though the sensors may not be faulty, the conditions can cause discrepancies to occur in the readings from different sensors. Such discrepancies can grow over time, and when they reach a certain level they may cause the train control system into which they feed to enter a "degenerate mode" which the control system can only exit by rebooting itself A hiatus such as this in the normal operation of the train control system can be a further source of delays and timetable disruption.

Conventionally, when conditions occur on a network that might lead to sliding or slipping (e.g. heavy rain, or heavy leaf fall), advance precautions are taken, such as imposing suitable maximum speed limits on those sections of the network where the conditions are expected to occur. This is illustrated schematically in Figure 1, which shows a train 101 having a control system (which generally includes a train management system (TMS), a signalling system, and a traction system) running on the network. The control system receives sensor information from sensors such as axle speed sensors 102. The train control system is in communication with a central control centre 103 via trackside communications devices (e.g. radio antennae). Typically the communication between the train 101 and the trackside communications devices is wireless, while the communication between the central control centre 103 and the trackside communications devices can be wired or wireless. The train 101 and the central control centre 103 both also receive satellite position information (i.e. GPS). An indicated section of the network is exposed to poor weather conditions and/or heavy leaf fall and thus wheel slide and slip are likely in this section. In reaction to this, the central control centre 103 imposes a precautionary maximum speed limit over a section of the network that includes, but also extends significantly beyond, the section exposed to difficult environmental conditions. The speed limit information can be relayed to the train 101 via the trackside communications devices, and the central control centre 103 can also control trackside signalling displays to show speed limits.

However, in order to eliminate wheel sliding or slipping, such pre-emptive action must over-compensate in time and in space, leading to unnecessary delays and timetable disruption.

Thus it would be desirable to be able to manage operation of trains on a rail network in such a way as to reduce instances of sliding and slipping, but without imposing unnecessary or overly broad (in time and space) speed restrictions.

One option is to provide train traction systems with a function that reduces decelerations and accelerations when sliding and slipping are detected. This is effective at avoiding further sliding or slipping, but the function only comes into operation on a given train after the phenomenon has already occurred on that train.

Another option is to provide train signalling systems with a function that detects occurrences of sliding and slipping based on the fluctuation of value inputs from the axle speed sensors. The function can then also correct the calculated speed from the sensors. This can be effective at preventing system entry into the "degenerate mode", with its subsequent need for a reboot. However, again, the function only comes into operation on a given train after the phenomenon occurs on that train.

The present invention has been devised in light of the above considerations.

Summary of the Invention

In a first aspect, the present invention provides a rail network management system for managing movements of trains on a rail network, the management system having a central control centre and a system of trackside communications devices in communication with the central control centre; wherein the central control centre is configured to: receive real time data which include sensor information from the trackside communications devices, the sensor information measuring performance parameters of trains on the network and/or measuring external environmental conditions of trains on the network; on the basis of the real time data, identify sections of the network where trains on the network may experience wheel slip and/or wheel slide and determine respective operational requirements for running trains through the identified sections without experiencing wheel slip and wheel slide; and communicate the identified sections and operational requirements to the trackside communications devices; wherein the system of trackside communications devices is configured to: receive the identified sections and operational requirements communicated by the central control centre; and transmit the communicated identified sections and operational requirements wirelessly to on-board control systems of trains on the network such that the train control systems can run their trains through the identified sections in accordance with the respective operational requirements; and wherein the system of trackside communications devices is further configured to: receive the sensor information by wireless transmission from the on-board train control systems of trains on the network; and communicate the sensor information to the central control centre for receipt thereby and inclusion in the real time data.

Thus the central control centre can make suitable decisions for train operation on the network based on real time data including information gathered from trains actually running on the network. In this way, the trains not only benefit from the centralised decision-making of the central control centre, but contribute to its decision-making process through their sensor information measuring train performance parameters and/or external environmental conditions. For example, if one train experiences sliding or slipping, or senses heavy rain or heavy fallen leaf accumulation at a given location on the network, that information can be processed by the central control centre for the benefit of subsequent trains passing through that location (e.g. by imposing a temporarily reduced maximum speed limit at the given location), the subsequent trains also providing feedback on the development of conditions at the location which can in turn indicate when the speed limit should be removed. This approach to rail network management is highly efficient, making use of many sources of real time information and enabling a "light touch" in regard to imposition of operational requirements which could lead to delays and timetable disruption.

The real time data received by the central control centre may further include weather information for the network and/or trackside equipment information from trackside equipment of the network. Weather information can be, for example, commercial weather reports and/or meteorological data (e.g. wind speed, wind direction, temperature, precipitation level etc.) measured by trackside weather stations.

Trackside equipment information can include trackside camera images, e.g. allowing leaf fall accumulations to be determined.

Generally, the performance parameters of trains on the network include train speed. The or each train may thus have one or more axle speed sensors which measure train speed by measuring rotational speeds of wheel axles of the train, and/or one or more radar speed sensors which measure train speed by measuring radar signals (such as Doppler radar or millimetre-wave radar). In particular, when the or each train has one or more axle speed sensors and one or more radar speed sensors, the operational requirements may include switching from measuring train speed using the axle speed sensors to measuring train speed by using the one or more radar speed sensors while running through the identified sections. In this way problems caused by discrepancies between readings from axle speed sensors can be avoided.

However, as well as train speed, other performance parameters, such as any one or more of weight of train, carriage acceleration (i.e. as measured by an accelerometer to assess ride quality), and availability of on-board equipment items such as sandbox and/or track surface air blower can be included in the sensor information.

The external environmental conditions of trains on the network may include weather conditions and/or leaf fall conditions. For example, the or each train may have one or more camera sensors to measure external environmental conditions.

The operational requirements may include any one, any two or all of: maximum speed limits for trains while running through the identified sections, gritting commands to control operation of train sandboxes to improve train wheel adherence while running through the identified sections, and blower commands to control operation of train air blowers for removal of leaves or moisture from track surfaces while running through the identified sections. Thus the operational requirements are compatible with trains continuing to run through the identified sections, while taking measures to avoid wheel slip and wheel slide.

In a second aspect, the present invention provides a combination of the rail network management system according to the first aspect, and one or more trains, each train having: one or more sensors configured to collect sensor information measuring performance parameters of the train and/or measuring external environmental conditions of the train; and an on-board train control system configured to: transmit the sensor information wirelessly to the system of trackside communications devices; and receive the identified sections and operational requirements transmitted wirelessly by the system of trackside communications devices; wherein each on-board train control system is further configured to run its train through the identified sections in accordance with the respective operational requirements.

The on-board train control system may include any one, any two or all of: a train management system, a train signalling system, and a train traction system.

When the operational requirements include gritting commands to control operation of train sandboxes to improve train wheel adherence while running through the identified sections, the or each train may further have one or more sandboxes. Similarly, when the operational requirements include blower commands to control operation of train air blowers for removal of leaves or moisture from track surfaces while running through the identified sections, the or each train may further have one or more air blowers.

In a third aspect, the present invention provides a train for operation on a rail network, the train having: one or more sensors configured to collect sensor information measuring performance parameters of the train and/or measuring external environmental conditions of the train; and an on-board train control system configured to: transmit the sensor information wirelessly to a system of trackside communications devices of the rail network; receive operational data transmitted wirelessly by the system of trackside communications devices, the operational data identifying sections of the network where trains on the network may experience wheel slip and/or wheel slide and providing respective operational requirements for running trains through the identified sections without experiencing wheel slip and wheel slide; and run its train through the identified sections in accordance with the respective operational requirements.

Thus the train is suitable for operation on the rail network managed by the rail network management system of the first aspect.

The train may have one or more axle speed sensors which measure train speed by measuring rotational speeds of wheel axles of the train, and/or one or more radar speed sensors which measure train speed by measuring radar signals (such as Doppler radar or millimetre-wave radar). In particular, when the train has one or more axle speed sensors and one or more radar speed sensors, the operational requirements may include switching from measuring train speed using the axle speed sensors to measuring train speed by using the one or more radar speed sensors while running through the identified sections.

The train may have one or more camera sensors to measure external environmental conditions, such as weather conditions and/or leaf fall conditions.

The operational requirements include maximum speed limits for trains while running through the identified sections.

The train may have one or more sandboxes, the operational requirements including gritting commands to control operation of the sandboxes to improve train wheel adherence while running through the identified sections.

The train may have one or more air blowers, the operational requirements including blower commands to control operation of the air blowers for removal of leaves or moisture from track surfaces while running through the identified sections The invention includes the combination of the aspects and preferred features described except where such a combination is clearly impermissible or expressly avoided.

Summary of the Figures

Embodiments and experiments illustrating the principles of the invention will now be discussed with reference to the accompanying figures in which: Figure 1 shows schematically a conventional rail network management system; and Figure 2 shows schematically a rail network management system according to the present invention.

Detailed Description of the Invention

Aspects and embodiments of the present invention will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned in this text are incorporated herein by reference.

Figure 2 shows schematically a rail network management system according to the present invention. Compared to the conventional system shown in Figure 1, there is still a central control centre 3 and trains 1 running on the network generally each have a control system, which may include a TMS, a signalling system, and a traction system. The trains also have axle speed sensors 2 which measure the speed of the train from the rotation of the axles of the wheels which in turn physically touch the track surface. However, in addition they may have radar speed sensors 4 which measure train speed by measuring radar signals (such as Doppler radar or millimetre-wave radar. In other words, the trains generally have at least one sensor 4 which measures train speed based on a method which does not rely on physical contact with the track surface. Other train sensors may measure train weight, which can vary with number of passengers and can influence braking performance, and/or carriage acceleration, which is relevant for ride quality. Sensors can also be provided to monitor the availability or lack of availability of specific equipment items, such as sandboxes and/or track surface air blowers, these items when operated contributing to adherence between wheel contact surfaces and track surfaces. The trains may also have camera sensors, typically at the front and/or the rear ends of the train, to measure external environmental conditions, such as local weather conditions and/or local leaf fall conditions.

The information from these sensors is collected by the trains' control systems and transmitted wirelessly over a suitable interface to the system of trackside communications devices, and from here is communicated wirelessly or by wires to the central control centre 3. The control centre 3 thus receives real time data including train performance parameters, such as train speed, and measurements of external environmental conditions to the trains. Included in these train performance parameters or external environmental conditions can be information provided by the train driver, e.g. in relation to any observations by the driver about the train performance or external environmental condition. The data format for driver observations can be, for example, voice recordings or symbolic information generated through an interface provided on the train control unit in the cab. In particular, the driver observations can be observations of actual occurrences of sliding or slipping.

Also available to the central control centre 3 is current weather information for the network and/or trackside equipment information from trackside equipment of the network. The weather information can be, for example, commercial weather reports and/or meteorological data (e.g. wind speed, wind direction, temperature, precipitation level etc.) measured by trackside weather stations. Trackside equipment information can include trackside camera images, e.g. allowing leaf fall accumulations to be determined.

In addition, the central control centre 3 and the trains 1 receive train satellite position information (i.e. GPS).

This incoming, real time data allows the central control centre 3 to identify with high degrees of certainty sections of the network where wheel slide and slip are likely to occur. Indeed, a given train's performance parameters received by the central control centre 3 may provide a first indication of actual slide and slip, rather than a prediction. The control centre 3 also determines suitable operational requirements, such as maximum speed limits to be imposed in the identified sections. The identified sections and their associated operational requirements are communicated to the trackside communications devices and then wirelessly transmitted to the on-board control systems of the trains 1. To provide a suitable safety factor, the identified sections where modified operation is to be imposed can be expanded slightly, as illustrated in Figure 2, but in general the extents of the identified sections, even when thus-expanded, can be substantially less than the extents of the sections of network for which precautionary maximum speed limit are imposed in the conventional system shown in Figure 1. This is largely made possible by the real time and continuously updated sensor information provided by the trains.

Indeed, because the network conditions are continuously monitored by further trains as they pass through the identified sections and their sensor information is sent to the central control centre 3, the lengths of time needed over which modified operation in the identified sections is needed can be reduced relative to the conventional system.

Thus the approach to rail network management provided by the rail network management system of Figure 2 is highly efficient, and enables a "light touch" in regard to imposition of operational requirements which could lead to delays and timetable disruption. In particular, impositions of maximum speed limits can be reduced in both space and time, and network operating densities can be maintained at higher levels. Moreover, the TMS of each train can warn the driver in advance on approach to a section where wheel slide and slip are likely to occur. This allows the driver to take pre-emptive action which can reduce the need for acceleration or deceleration in the section, reducing the likelihood of sliding and slipping still further.

The operational requirements imposed by the central control centre 3 are typically maximum speed limits.

However, other types of operational requirements can also be imposed to reduce the severity/possibility of slip/slide. For example, the trains 1 may be equipped with sandboxes and/or air blowers 5. The operational requirements may thus include gritting commands to control operation of the sandboxes to improve train wheel adherence while running through the identified sections, and/or blower commands to control operation of the air blowers for removal of leaves or moisture from track surfaces while running through the identified sections. Such operational requirements are also compatible with trains continuing to run through the identified sections while avoiding wheel slip and wheel slide. In this way, and especially in relation to sensors associated with a lead car, the likelihood of occurrence of speed sensor calculation discrepancies caused by slip/slide can be reduced, and thus the possibility of operational standstill imposed by a need to reboot a train control system from a "degenerate mode" can be decreased.

When the trains have both axle speed sensors 2 and radar speed sensors 4, the operational requirements may include switching from measuring train speed using the axle speed sensors to measuring train speed by using the one or more radar speed sensors while running through the identified sections. In this way also, problems caused by discrepancies between readings from axle speed sensors can be avoided. In other words, switching the position detection system can prevent a degradation in the accuracy of measuring vehicle position that might otherwise be caused by wheel slip or slide.

Consequently, it is possible to shorten the protective track occupancy distance reserved for each train, allowing the operational density of trains on the rail network to be increased.

More specifically, a radar speed sensor 4 is preferably installed at a lead car of a train. Typically, axle speed sensors 2 are installed at both ends of a train set, in other words, at a lead car and an end car, and both feed sensing outputs to the train control system in order to calculate the speed of the train. When running over tracks having a normal surface condition, both speed sensors 2 provide similar outputs, and the likelihood of measurement discrepancy is low. In contrast, under degraded running conditions when the track surface conditions is poor, the likelihood of measurement discrepancy increases, especially due to worsening measurement accuracy from the speed sensors 2 at the lead car. As a result, if relying on the speed sensors 2 alone, train operators can be forced to reduce train maximum speeds merely to avoid such discrepancies, even if higher speeds would otherwise be safe. However, by measuring train speed under such circumstances with the radar speed sensor 4 instead of lead car axle speed sensor 2, the possibility of such a problems emerging can be reduced.

The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.

For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.

Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

Throughout this specification, including the claims which follow, unless the context requires otherwise, the word "comprise" and "include", and variations such as "comprises", "comprising", and "including" will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

It must be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent "about," it will be understood that the particular value forms another embodiment. The term "about" in relation to a numerical value is optional and means for example +/-10%.

Claims

Claims: 1. A rail network management system for managing movements of trains on a rail network, the management system having a central control centre and a system of trackside communications devices in communication with the central control centre; wherein the central control centre is configured to: receive real time data which include sensor information from the trackside communications devices, the sensor information measuring performance parameters of trains on the network and/or measuring external environmental conditions of trains on the network; on the basis of the real time data, identify sections of the network where trains on the network may experience wheel slip and/or wheel slide and determine respective operational requirements for running trains through the identified sections without experiencing wheel slip and wheel slide; and communicate the identified sections and operational requirements to the trackside communications devices; wherein the system of trackside communications devices is configured to: receive the identified sections and operational requirements communicated by the central control centre; and transmit the communicated identified sections and operational requirements wirelessly to on-board control systems of trains on the network such that the train control systems can run their trains through the identified sections in accordance with the respective operational requirements; and wherein the system of trackside communications devices is further configured to: receive the sensor information by wireless transmission from the on-board train control systems of trains on the network; and communicate the sensor information to the central control centre for receipt thereby and inclusion in the real time data.
2. The rail network management system according to the claim 1, wherein the real time data received by the central control centre further includes weather information for the network and/or trackside equipment information from trackside equipment of the network.
3. The rail network management system according to the claim 1 or 2, wherein the performance parameters of trains on the network include train speed.
4. The rail network management system according to the claim 3, wherein the or each train has one or more axle speed sensors which measure train speed by measuring rotational speeds of wheel axles of the train, and one or more radar speed sensors which measure train speed by measuring radar signals, and the operational requirements include switching from measuring train speed using the axle speed sensors to measuring train speed by using the one or more radar speed sensors while running through the identified sections.
5. The rail network management system according to any one of the previous claims, wherein the external environmental conditions of trains on the network include weather conditions and/or leaf fall conditions.
6. The rail network management system according to the claim 5, wherein the or each train has one or more camera sensors to measure external environmental conditions.
7. The rail network management system according to any one of the previous claims, wherein the operational requirements include any one, any two or all of: maximum speed limits for trains while running through the identified sections, gritting commands to control operation of train sandboxes to improve train wheel adherence while running through the identified sections, and blower commands to control operation of train air blowers for removal of leaves or moisture from track surfaces while running through the identified sections.
8. A combination of the rail network management system according to any one of the previous claims, and one or more trains, each train having: one or more sensors configured to collect sensor information measuring performance parameters of the train and/or measuring external environmental conditions of the train; and an on-board train control system configured to: transmit the sensor information wirelessly to the system of trackside communications devices; and receive the identified sections and operational requirements transmitted wirelessly by the system of trackside communications devices; wherein each on-board train control system is further configured to run its train through the identified sections in accordance with the respective operational requirements.
9. The combination of the rail network management system and the one or more trains according to claim 8 as dependent on claim 7, wherein the or each train further has one or more sandboxes and/or one or more air blowers for removal of leaves or moisture from track surfaces
10. A train for operation on a rail network, the train having: one or more sensors configured to collect sensor information measuring performance parameters of the train and/or measuring external environmental conditions of the train; and an on-board train control system configured to: transmit the sensor information wirelessly to a system of trackside communications devices of the rail network; receive operational data transmitted wirelessly by the system of trackside communications devices, the operational data identifying sections of the network where trains on the network may experience wheel slip and/or wheel slide and providing respective operational requirements for running trains through the identified sections without experiencing wheel slip and wheel slide; and run its train through the identified sections in accordance with the respective operational requirements.
11. The train according to the claim 10, which has one or more axle speed sensors which measure train speed by measuring rotational speeds of wheel axles of the train, and one or more radar speed sensors which measure train speed by measuring radar signals, and the operational requirements include switching from measuring train speed using the axle speed sensors to measuring train speed by using the one or more radar speed sensors while running through the identified sections.
12. The train according to claim 10 or 11, which has one or more camera sensors to measure external environmental conditions.
13. The train according to any one of claims 10 to 12, wherein the operational requirements include maximum speed limits for trains while running through the identified sections.
14. The train according to any one of claims 10 to 13, which has one or more sandboxes, the operational requirements including gritting commands to control operation of the sandboxes to improve train wheel adherence while running through the identified sections.
15. The train according to any one of claims 10 to 14, which has one or more air blowers, the operational requirements including blower commands to control operation of the air blowers for removal of leaves or moisture from track surfaces while running through the identified sections.