Rail vehicle integrity proving device and method

Abstract

The rail vehicle integrity check device 20 comprises a first connector 21 adapted to form an airtight connection with the brake pipe 22 mounted on the rear wagon of a rail vehicle, and a second connector 23 adapted to form an airtight connection with a main reserve pipe 24 mounted on the rear wagon of the rail vehicle. A one-way valve 25, adapted to be in fluid communication with the brake pipe and the main reserve pipe of the rear wagon of the rail vehicle, is mounted between the first 21 and second 23 connectors. This may be done by providing elbow joints 26, 27 between each of the connectors 21, 23 respectively and the one-way valve 24. For convenience, the one-way valve 24 and any elbow joints 26, 27 provided may be housed within an external casing 28 in order to prevent the ingress of dirt whilst in use. The pipe connectors 21, 23 may be connectors used widely within the railway industry, such as angle cocks or gladhand couplers, or screw thread connectors, push and turn locking mechanisms or push fit connectors. Suitable flexible closure element one-way valves 25 include, but are not limited to, diaphragm check valves, duckbill valves or reed valves. Suitable hinged closure element one-way valves include, but are not limited to, swing check valves, butterfly check valves or tilting flap check valves. The one-way valve 25 comprises a chamber 29 and a pressure-sensitive closure element 30 abutting a closure surface 31 within the chamber 29.

Description

The present invention relates to methods and apparatus for determining the integrity of a rail vehicle, in particular a freight train or passenger train formed of individual coaches. It is a requirement of safe signalling of railways that proof of train integrity can be determined, that is, proof that the train has been correctly assembled as one unit, and has remained as one unit, not split into two or more sections. This is usually provided by the use of an end-of-train marking device, such as a tail lamp or marker board so that an observer or a camera for remote observation can determine that an actual rearmost wagon of a train is indeed intended to be the rearmost wagon. Conventional arrangements for detecting train integrity include detection systems such as track circuits or axle counters. However, planned upgrades such as European Train Control System (ETCS) Level 3 require removal of trackside train detection equipment. This allows improvements due to reduced infrastructure cost and maintenance burden. Such planned upgrades also introduce the possibility of increased capacity by allowing trains to run closer together. However, by removing the trackside equipment it will no longer be possible to use this to determine the integrity of a rail vehicle. For example, in conventional systems at ETCS Levels 0,1 and 2, axle countering devices may be used to determine whether the number of axles registered as a rail vehicle passes over the device is the same as that when the rail vehicle left the last signal block or depot. Without the ability to use trackside equipment, a rail vehicle needs to become self-sufficient in determining its own integrity. One solution to this issue is proposed in EP4079596B1, where a spring-biased valve is mounted on the break pipe and main reserve pipe of a train. The train integrity is proved if a pressure increase in the main reserve pipe sufficient to overcome the spring bias when the brake pipe is at atmospheric pressure is detected on the brake pipe at the locomotive. By using a spring-biased valve, however, the system relies on the resilience of the spring, both in terms of the initial pressure increase required to overcome the spring force exerted by the spring and in terms of its lifetime, over which the spring force may change and / or the spring become weakened in some other manner. There exists, therefore, a need to provide an ETCS Level 3-compliant rail vehicle integrity test whilst overcoming the issues of prior art systems. The present invention aims to address these issues, by providing, a rail vehicle integrity check device, comprising: a first connector adapted to form an airtight connection with a brake pipe mounted on the rear wagon of a rail vehicle; a second connector adapted to form an airtight connection with a main reserve pipe mounted on the rear wagon of the rail vehicle; and a one-way valve adapted to be in fluid communication with the brake pipe and the main reserve pipe of the rear wagon of the rail vehicle; wherein the one-way valve comprises a chamber and a pressure-sensitive closure element abutting a closure surface within the chamber, the closure element being pressure operated and adapted to be biased against the closure surface solely by a positive air pressure between the main reserve pipe and the brake pipe. Since the one-way valve does not rely on a spring pressure to be overcome to move the pressure-sensitive closure element, much smaller air leaks can be detected than with prior art systems. In addition, the integrity test is level 3 ETCS compliant as it is carried out from the rail vehicle itself, without the need for an external check. Preferably, the closure element is adapted to be moved away from the closure surface by either an increase in air pressure in the brake pipe or a decrease in air pressure in the main reserve pipe. Preferably, the closure element is either a flexible element or a hinged element. The closure element may be a flexible element and the one way valve is one of a diaphragm check valve, a duckbill valve or a reed valve. Alternatively, the closure element may be a hinged element and the one way valve is one of a swing check valve, a butterfly check valve or a tilting flap check valve. Preferably, the first and second connectors comprise screw thread connectors, push and turn locking mechanisms or push fit connectors. The invention also provides a method of performing a rail vehicle integrity check comprising: connecting a rail vehicle integrity check device as described above to a main reserve pipe and a brake pipe both mounted on the rear wagon of a rail vehicle such that the closure element is biased against the closure surface solely by a positive air pressure between the main reserve pipe and the brake pipe; creating a negative air pressure im balance between the main reserve pipe and the brake pipe such that the closure element moves away from the closure surface and the one-way valve opens to allow air into the main reserve pipe from the brake pipe; and detecting the change in air pressure from the air entering the main reserve pipe from the brake pipe at a locomotive of the rail vehicle; wherein an increase in pressure in the main reserve pipe indicates that the brake pipe and the main reserve pipe form an air circuit implying that all wagons on the rail vehicle, including the locomotive, are coupled together correctly. Preferably, the method further comprises increasing the air pressure in the brake pipe from the locomotive at the front of the train. The main reserve pipe may also be drained to atmospheric pressure from the locomotive before increasing the air pressure in the brake pipe. The invention further provides a method of performing a static brake test on a rail vehicle comprising: measuring the holding capacity of the brakes when the rail vehicle is at standstill; and performing a rail vehicle integrity check using either the rail vehicle integrity check device outlined above or the method as outlined above. The invention will now be described by way of example only, and with reference to the accompanying drawings, in which: Figure 1 is a schematic illustration of a compressed air braking system on a rail vehicle; Figure 2 is a schematic illustration of a rail vehicle integrity check device in accordance with an embodiment of the present invention in a closed position; Figure 3 is a schematic illustration of a rail vehicle integrity check device in accordance with an embodiment of the present invention in an open position; Figure 4 is a flowchart illustrating a method of performing a rail vehicle integrity check in accordance with embodiments of the present invention; and Figure 5 is a flowchart illustrating a method of performing a static brake test on a rail vehicle. The embodiments of the present invention take the approach that a rail vehicle integrity check device may be a relatively simple coupling applied at the rear of the rail vehicle, avoiding the use of a spring as in the prior art designs. The device comprises a first connector adapted to form an airtight connection with a brake pipe mounted on the rear wagon of a rail vehicle and a second connector adapted to form an airtight connec tion with a main reserve pipe mounted on the rear wagon of the rail vehicle. A one-way valve is fitted and adapted to be in fluid communication with the brake pipe and the main reserve pipe of the rear wagon of the rail vehicle. This comprises a chamber and a pressure-sensitive closure element abutting a closure surface within the chamber. The pressure-sensitive closure element can tale several forms, such as diaphragm-based valves or flap-based valves, with the closure element being pressure operated and adapted to be biased against the closure surface solely by a positive air pressure between the main reserve pipe and the brake pipe. The device is therefore unaffected by issues relating to spring valves or other valve arrangements that rely on forces other than positive air pressure to bias a closure element against a closure surface. Figure 1 is a schematic diagram of a compressed air braking system on a rail vehicle. The braking system 1 comprises a brake pipe 2 and a main reservoir pipe 3 that each run the length of a wagon of the rail vehicle. Between the wagons, the sections of brake pipe 2 and main reservoir 3 are joined using valved joints 4, such as angle cocks. At each wheel 5, a brake block 6 is provided, the position of which is controlled by a brake cylinder 7. The main brake pipe 2 connects to the brake cylinder 7 by means of a triple valve 8, which also provides an outlet to exhaust 9 and an inlet from an auxiliary reservoir 10. The auxiliary reservoir 10 is fed by the main reservoir pipe 3, which in turn is fed from the main reservoir 11 and compressor 12. A one-way valve 13 is provided between the main reservoir pipe 3 and the auxiliary reservoir 10. A driver's brake valve 14 connects the main pipe 2 and the main auxiliary pipe 3 at the locomotive. In use, the driver's brake valve 14 is used to release air pressure in the main brake pipe 2, which is detected at the triple valve. This causes the auxiliary reservoir 10 to pressurise the brake cylinder 7, forcing the brake block 6 against the wheel 5. To release the brake, the driver's brake valve is used to vent the air from the brake cylinder 7 via the exhaust outlet 9 in the triple valve 8, and the auxiliary reservoir 10 is refilled via the one-way valve 13 from the main reserve pipe 3. Several events may cause a sudden depressurisation of the braking system 1: • Emergency braking by the driver; • Emergency braking by the conductor; • A passenger emergency stop; • A burst pipe; or • A derailment / uncoupling causing the pipes to separate. For the driver, it is imperative to know when the cause of the depressurisation is a burst piped or a derailment / uncoupling, as well as to know whether or not the wagons are fully coupled before leaving a depot. This is where the device of the present invention is particularly useful. Figure 2 is a schematic illustration of a rail vehicle integrity check device in accordance with an embodiment of the present invention in a closed position. In this example, the one-way valve illustrated is a swing check valve, but this should not be taken to be limiting. The rail vehicle integrity check device 20 comprises a first connector 21 adapted to form an airtight connection with the brake pipe 22 mounted on the rear wagon of a rail vehicle, and a second connector 23 adapted to form an airtight connection with a main reserve pipe 24 mounted on the rear wagon of the rail vehicle. A one-way valve 25, adapted to be in fluid communication with the brake pipe and the main reserve pipe of the rear wagon of the rail vehicle, is mounted between the first 21 and second 23 connectors. This may be done by providing elbow joints 26, TJ between each of the connectors 21, 23 respectively and the one-way valve 24. For convenience, the one-way valve 24 and any elbow joints 26, 27 provided may be housed within an external casing 28 in order to prevent the ingress of dirt whilst in use. The pipe connectors 21, 23 may be connectors used widely within the railway industry, such as angle cocks or gladhand couplers, or screw thread connectors, push and turn locking mechanisms or push fit connectors. Suitable flexible closure element one-way valves 25 include, but are not limited to, diaphragm check valves, duckbill valves or reed valves. Suitable hinged closure element one-way valves include, but are not limited to, swing check valves, butterfly check valves or tilting flap check valves. The one-way valve 25 comprises a chamber 29 and a pressure-sensitive closure element 30 abutting a closure surface 31 within the chamber 29. The closure element 30 is pressure operated and adapted to be biased against the closure surface 31 solely by a positive air pressure between the main reserve pipe 24 and the brake pipe 22. When the one-way valve 25 is in the closed position with the closure element 30 biased against the closure surface 31, the air pressures in the main brake pipe 22 and the main reserve pipe 24 are at an equilibrium. This provides an integrity check to the driver, since if all of the pipes and pipe couplings between the wagons are intact, the rail vehicle formation is fully integrated. The main advantage of such an integrity check is that it meets Level 3 ETCS requirements for proving train integrity. Figure 3 is a schematic illustration of a rail vehicle integrity check device in accordance with an embodiment of the present invention in an open position. In this figure, the one-way valve 25 of Figure 2 is shown in an open position. The closure element 30 is adapted to be moved away from the closure surface 31 by either an increase in air pressure in the brake pipe 22 or a decrease in air pressure in the main reserve pipe 24. In Figure 3 the closure element 30 biased away from the closure surface 31 by a positive pressure in the main reserve pipe 24. This indicates an issue in the brake pipe 22, where a pressure drop has occurred. This pressure drop is registered in the locomotive where an alarm is initiated. This may be an audible (a buzzer or bell), visual (constant or flashing light) or combination of audible and visual elements alarm. This is also the case if a pressure increase occurs in the main reserve pipe 24, where again, an alarm will be created in the locomotive on detection of the pressure drop. This is the case where, for example, a fault has occurred in the braking system itself. Figure 4 is a flowchart illustrating a method of performing a rail vehicle integrity check in accordance with embodiments of the present invention. The method 400 beings, at step 402, with connecting a rail vehicle integrity check device 20 as described above to a main reserve pipe 24 and a brake pipe 22 both mounted on the rear wagon of a rail vehicle such that the closure element 30 is biased against the closure surface 31 solely by a positive air pressure between the main reserve pipe 24 and the brake pipe 22. Next, a negative air pressure imbalance is created between the main reserve pipe 24 and the brake pipe 22 at step 404. This causes the closure element 30 to move away from the closure surface 31 such that the one-way valve 25 opens to allow air into the main reserve pipe 24 from the brake pipe 22. At step 406 the change in air pressure from the air entering the main reserve pipe 24 from the brake pipe 22 is detected at a locomotive of the rail vehicle. This increase in pressure in the main reserve pipe 24 indicates that the brake pipe 22 and the main reserve pipe 24 form an air circuit implying that all wagons on the rail vehicle, including the locomotive, are coupled together correctly. The driver is able to increase the pressure in the brake pipe 22 from the locomotive using the brake valve 14 in the locomotive. The main reserve pipe may be drained to atmospheric pressure from the locomotive before increasing the air pressure in the brake pipe if desired. Figure 5 is a flowchart illustrating a method of performing a static brake test on a rail vehicle. The method 500 requires, at step 502, measuring the holding capacity of the brakes when the rail vehicle is at standstill. Once this is known, a rail vehicle integrity check device 20 as described above is connected to the main reserve pipe 24 and a brake pipe 22 both mounted on the rear wagon of a rail vehicle in step 504. The closure element 30 should be biased against the closure surface 31 solely by a positive air pressure between the main reserve pipe 24 and the brake pipe 22. Next, a negative air pressure imbalance is created between the main reserve pipe 24 and the brake pipe 22 at step 506. This causes the closure element 30 to move away from the closure surface 31 such that the one-way valve 25 opens to allow air into the main reserve pipe 24 from the brake pipe 22. At step 508 the change in air pressure from the air entering the main reserve pipe 24 from the brake pipe 22 is detected at a locomotive of the rail vehicle. This increase in pressure in the main reserve pipe 24 indicates that the brake pipe 22 and the main reserve pipe 24 form an air circuit implying that all wagons on the rail vehicle, including the locomotive, are coupled together correctly, and the static break test is successful. These and other embodiments based on the invention outlined above are limited only by the scope of the appended claims.

Claims

1. Rail vehicle integrity check device, comprising:a first connector adapted to form an airtight connection with a brake pipe mounted on the rear wagon of a rail vehicle;a second connector adapted to form an airtight connection with a main reserve pipe mounted on the rear wagon of the rail vehicle; anda one-way valve adapted to be in fluid communication with the brake pipe and the main reserve pipe of the rear wagon of the rail vehicle;wherein the one-way valve comprises a chamber and a pressure-sensitive closure element abutting a closure surface within the chamber, the closure element being pressure operated and adapted to be biased against the closure surface solely by a positive air pressure between the main reserve pipe and the brake pipe.

2. Rail vehicle integrity check device as claimed in claim 1, wherein the closure element is adapted to be moved away from the closure surface by either an increase in air pressure in the brake pipe or a decrease in air pressure in the main reserve pipe.

3. Rail vehicle integrity check device as claimed in claim 2, wherein the closure element is either a flexible element or a hinged element.

4. Rail vehicle integrity check device as claimed in claim 3, wherein the closure element is a flexible element and the one way valve is one of a diaphragm check valve, a duckbill valve or a reed valve.

5. Rail vehicle integrity check device as claimed in claim 3, wherein the closure element is a hinged element and the one way valve is one of a swing check valve, a butterfly check valve or a tilting flap check valve.

6. Rail vehicle integrity check device as claimed in any preceding claim, wherein the first and second connectors comprise screw thread connectors, push and turn locking mechanisms or push fit connectors.

7. A method of performing a rail vehicle integrity check comprising: connecting a rail vehicle integrity check device as claimed in any of claims 1 to 6 to a main reserve pipe and a brake pipe both mounted on the rear wagon of a rail vehicle such that the closure element is biased against the closure surface solely by a positive air pressure between the main reserve pipe and the brake pipe;creating a negative air pressure imbalance between the main reserve pipe and the brake pipe such that the closure element moves away from the closure surface and the one-way valve opens to allow air into the main reserve pipe from the brake pipe; and detecting the change in air pressure from the air entering the main reserve pipe from the brake pipe at a locomotive of the rail vehicle;wherein an increase in pressure in the main reserve pipe indicates that the brake pipe and the main reserve pipe form an air circuit implying that all wagons on the rail vehicle, including the locomotive, are coupled together correctly.

8. Method as claimed in claim 7, further comprising: increasing the air pressure in the brake pipe from the locomotive at the front of the train.

9. Method as claimed in claim 8, further comprising: draining the main reserve pipe to atmospheric pressure from the locomotive before increasing the air pressure in the brake pipe.

10. A method of performing a static brake test on a rail vehicle comprising: measuring the holding capacity of the brakes when the rail vehicle is at standstill;andperforming a rail vehicle integrity check using either the rail vehicle integrity check device as claimed in claims 1 to 6 or the method as claimed in claims 7 to 9.

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