GB2424288A

GB2424288A - Train door control system

Info

Publication number: GB2424288A
Application number: GB0602894A
Authority: GB
Inventors: Brian Robert Sweeney
Original assignee: AEA Technology PLC
Current assignee: Ricardo AEA Ltd
Priority date: 2005-03-17
Filing date: 2006-02-14
Publication date: 2006-09-20
Anticipated expiration: 2026-02-14
Also published as: GB0602894D0; GB2424288B; GB0505452D0

Abstract

A system for controlling the operation of the doors (32) of a railway train, consists of two parts. Firstly, the system provides radio-frequency identification (RFID) tags (18, 20) installed adjacent to each end of each platform (14, 16), the tags (18, 20) being coded with different data which may be interpreted as "door closed" and "door released" respectively. Secondly, there are radio transmitter/receiver units (34) on each side of each carriage (24) in the train to detect the tags (18, 20), these units being mounted on the train in the vicinity of each door (32), and providing an electrical output signal to control opening of that door. This can enable longer trains to be operated, without risk of passengers disembarking where there is no platform adjacent to the train.

Description

Door Control System This invention relates to a system for controlling the

operation of the doors of a railway train.

For passenger safety it is important that train doors are not free to open except when the train is stationary next to a platform. On many trains the doors are locked electrically, and a member of the train crew must release all the locks of the appropriate side of the train, at each station, so that passengers can open the doors. This does not overcome the problem that a train may be longer than the platform, in which case only some of the doors should be unlocked. Such issues have been considered in various publications. For example US 4 269 377 describes a door control for trains in which an antenna is provided at each station, the length of the antenna being substantially the same as that of the station. Antennas are provided on the front of the train and the back of the train, and if both these antennas receive information then the vehicle door control allows the doors to open when the vehicle is stationary.

Another system is described in US 6 341 563 in which each door is provided with an acoustic sensor to detect the presence of a platform; if a platform is sensed, then opening of the door is enabled.

According to the present invention there is provided a system for controlling the operation of the doors of a railway train, the system comprising a radio-frequency identification tag installed adjacent to each end of a platform, alongside the track and outside the vehicle gauge, the tags being coded with one of two different identification data; and the train having radio transmitter/receiver units to detect the tags, these units being mounted on the train in the vicinity of each door, and providing an electrical output signal to control opening of that door.

Preferably the transmitter/receiver units are low power units, the radio power transmitted preferably being no greater than 1 W, more preferably no more than 500 mW.

A radio-frequency identification tag (RFID tag), when activated by receipt of a radio signal of its operating frequency, transmits the data with which it has been encoded. This data is then detected and interpreted by the transmitter/receiver unit. Preferably the RFID tag is a passive device, that is to say it is powered by the signal that it receives. Such a passive tag does not require any battery or external power supply, and can be expected to have a long service life. A passive tag can be detected only within a short distance, this range typically being about 1 m. Alternatively the RFID tag may be a semi-passive tag, this requiring a battery but the expected battery life time being several years; this would provide the benefit of an increased detection range, and a faster response time, although such semi- passive tags are more expensive to manufacture, and must be replaced before the battery expires.

Preferably the RFID tags and the transmitter/ receiver units operate in the UHF or microwave frequency range. Suitable frequencies would be therefore in the range 860 MHz-930 MHz (UHF) or 2.45 GHz (microwave) Such high frequency transmissions are not significantly affected by the presence of steel structures, and do not need large antennas, and provide higher data transfer rates and therefore faster identification compared with lower frequency systems. Microwave frequency transmissions are somewhat more susceptible to performance degradation due to the presence of metals and liquids than are UHF, and are also directional. The preferred operating frequency in Europe and the UK would be a frequency in the UHF range, 868-870 MHz, as this provides a good balance between range and performance, and is not likely to suffer from interference.

The RFID tags are encoded with binary data, the data preferably being transmitted by frequency modulation. If trains run along the line adjacent to the platform in only one direction, so one end of the platform can be identified as the inbound end and the other end as the outbound end, then the tag adjacent to the inbound end would provide a data signal to permit door release, while the tag adjacent to the outbound end would provide a data signal to prevent door release. To avoid confusion when installing the tags, they are preferably clearly distinguishable to the naked eye, for example being colour-coded. However, in some cases two-way running will be expected; and it is possible, even with one-way running, for a train to travel backwards when adjacent to a platform (for example if the driver overshoots the designated stopping point) . It is therefore preferable for pairs of the RFID tags to be provided at each end of the platform; within each pair, the tag closest to the end of the platform provides a data signal to prevent door release, while the other tag of that pair provides a data signal to permit door release. Indeed, an additional tag that provides the data signal to prevent door release might be provided adjacent to the line beyond the inbound end of the platform.

Each transmitter/receiver unit preferably incorporates an integral antenna, to reduce the probability of impedance mismatch when using coaxial cable to link a unit to an antenna. Furthermore the transmitter/receiver unit preferably incorporates separate antennas for transmission and reception, as using a common antenna may slow the overall response time, and consequently limit the maximum vehicle speed at which a tag can be read. Where doors are provided near the ends of a vehicle it would be preferable to provide separate transmitter/receiver units adjacent to all four doors; in other cases it may be sufficient to provide transmitter/receiver units at the middle of the vehicle, on each side.

The invention is particularly advantageous in situations where it would be desirable to operate longer trains, in order to increase capacity, but in which some of the stations have platforms that are not long enough to take such trains.

The invention will now be further and more particularly described, by way of example only, and with reference to the accompanying drawings in which: Figure 1 shows a plan view of part of a railway station, showing the ends of two platforms, with RFID tags of the invention; Figure 2 shows a side view of a passenger railway carriage incorporating radio/transmitter units of the invention; and Figure 3 shows a circuit diagram of the door control mechanism in the railway carriage of figure 2.

Referring now to figure 1, this shows a plan view of part of a railway station, showing two parallel railway tracks 10 and 12 which are primarily intended for travel in opposite directions (as indicated by the arrows A), which pass between two parallel platforms 14 and 16.

Near each end of each platform 14 and 16 are installed two passive RFID tags 18 and 20, spaced apart along the platform by 3 m in this example, each tag 18 and 20 being installed on the vertical face of the platform 14 and 16 a short distance below the top surface. In each case the tag 18 is 2 m from the end of the respective platform. In each case the tag 18 closer to the end of the platform is marked with a red dot and provides a signal which can be interpreted as meaning that doors are not to open, while the tag 20 further from that end of the platform is marked with a green dot and provides a different signal, which can be interpreted as meaning that doors are free to open.

Each tag 18 or 20 consists of a microprocessing circuit for control and data management purposes, an appropriate memory, and an antenna and radiofrequency receiver and transmission circuit, and would typically be embedded in plastic for protection from the weather. The tags 18 and 20 in this case are intended to operate at 869 MHz, and might comprise an integrated circuit, and an etched copper strip antenna mounted on a polyester backing sheet, and then embedded in plastic. The resulting tag may for example be 100 mm long, 50 mm wide and 15 mm thick.

Referring to figure 2, a railway carriage 24 consists of a vehicle body 26 supported on bogies 28 with wheels 30 that rest on one of the tracks, say track 10.

In this example the overall length of the carriage 24 is 19.3 m, and it has doors 32 on each side of the body 26 at about one- third of the way along the carriage 24 from each end. On each side of the carriage 24 there is installed a transmitter/receiver module 34 mounted just below the floor of the body 26. This module 34 consists of a protective metal housing enclosing the electronic circuitry from which projects a receiving antenna and a transmitting antenna, which for example may be a quarter- wave whip aerial, a helical antenna, or a ceramic antenna.

The module 34 is limited to 500 mW transmitted power at the operating frequency (868-870 MHz) . It can consequently only receive a signal from a RFID tag 18 or if it is within a range of about 1 m, as the signal must be strong enough to power operation of the tag.

These ranges are shown as the broken circles 36 in figure 1, and it will be appreciated that this range is sufficiently short that the module 34 will not receive signals from both the tags 18 and 20 on the same platform (say 14) at the same time, and indeed that only the module 34 on the side of the carriage 24 adjacent to the platform will receive signals from the tags 18 and 20, as the module 34 on the other side of the carriage is too far from the tags 18 and 20.

Referring now to figure 3 there is shown the circuit diagram of the door control mechanism for the carriage 24 of figure 2. It will be appreciated that there are several train wires which run the length of the train and which enable the driver to send control signals to various features in each carriage; one such train wire 40 enables the driver to send a control signal to the left hand door relays 42L (i.e. the doors on the left-hand side of the carriage 24), SO that those doors 32 can be unlocked, while another such train wire 41 enables the driver to send a control signal to the right-hand door relays 42R; 44 is a spare train wire. These features are conventional.

In this example the carriage 24 is provided with a power supply unit 46 connected to the train's supply line 47, at 110 V in this case, and to the battery negative line 48, and providing outputs at 12 V (for supply to relays) and 5 V (to operate the RF transmitter and receiver circuits), which are supplied to the RF transmitter/receiver modules 34 on each side of the carriage 24. Each module 34 provides an output signal, when it receives a door release signal from a tag 20, which is used to energise a relay 50 that enables the doors 32 to be released: the module 34L on the left-hand side of the carriage 24 energises a left-hand relay 50L and the module 34R on the right-hand side energises a right-hand relay 50R. This may for example be a solid- state relay with an optocoupler (such as Teledyne DS6R3E - trade mark) . The relay remains energised until the module 34 receives a code from a tag 20 to prevent door release (although if there is a loss of power to the system, the relay will deenergise, and remain deenergised until a door release signal is again received) . Each relay 50, when energised, closes two normally-open series relay contacts 52 which are connected between the wire 40 or 41 and the respective door relay 42L or 42R.

Thus in use, as a train approaches the platform 14 in the direction of the corresponding arrow A, as each carriage passes the end of the platform the left-hand module 34L receives a signal back from the tag 18 which prevents energisation of the left-hand relay 50L. After a short interval, the carriage 24 will pass the next tag 20, and so the left-hand module 34L receives a signal which causes energisation of the left-hand relay 50L.

Assuming for example that the train consists of twelve carriages, but that the platform 14 is only long enough for eight, and that the train stops with the front carriage no further along than the tag 20 at the other end of the platform. Each of the left-hand relays 50L in the front eight carriages 24 will therefore be energised, while the corresponding left-hand relays 50L in the other four carriages 24 will not have reached the door release tag 20 at the start of the platform 14, and therefore will not be energised.

When the train has stopped, the driver will activate the door release mechanisms on the left-hand side of the train, sending a signal along the train wire 40 to the door relays 42L. However, because of the relay contacts 52, only the doors in the front eight carriages 24 will be released. This ensures that the doors in the other carriages 24 that are not adjacent to the platform 14 cannot be unintentionally opened.

Prior to departing, the driver will check that all the doors 32 are closed (in some cases this would entail activating a door close mechanism, so that any open doors are closed), and the door relays 42L will be deactivated so that the doors 32 cannot be opened. As the train leaves the platform 14 each carriage 24 in succession will pass the door close tag 18 at the far end of the platform, so that every relay 50L in the train is deenergised.

The leading carriage 24 in the train preferably also provides a signal to the driver to indicate the side of the train on which the doors are free to open, for example with an additional switch controlled by the relay 50L or 50R. If the train goes too far before stopping, so that the leading carriage 24 has gone beyond the platform end tag 18, the driver will be made aware by this signal going out. There is no danger of passengers opening a door that is not adjacent to the platform 14, because only in those carriages 24 that are adjacent to the platform will the corresponding relay 50L be energised. If the train enters a station where there are platforms on both sides of the train, the door release tags 20 will activate the relays 50 on both sides of the train; this will be evident from the driver's display.

The driver can of course determine on which side the doors are actually released, by supplying a signal to either train wire 40 or 41, or both.

Preferably an override system is provided to override the effect of the selective door opening relays 50. This uses the spare train wire 44, and incorporates an override relay 55 which closes relay switches 56 in parallel with the relay contacts 52 in the lines to both the door relays 42L and 42R. This may be used during maintenance, for example; and also, if the train is stationary and the power supplies are switched off, then the selective relays 50 will all be deenergised, and it will not be possible to release the access doors 32 until the override system is activated.

It will be appreciated that this embodiment is described by way of example only, and that a door control system of the invention may differ from that described.

For example, to ensure that all the relays 50 are deenergised as a train approaches a station an additional door close tag 18 may be provided, for example on a line side post, a short distance before you reach the beginning of the platform, and these may be provided on both sides of each line 10 and 12.

In a further modification, each transmitter/receiver module 34 may also contain a non-volatile memory or a bistable circuit which records or remembers the last signal received. Hence if there is a loss of power, for example if the train is berthed for a prolonged period at a station and the 110 V supply line 47 is therefore deenergised, then when the power is turned on again each module 34 will return to the state it had been in before - 10 - the loss of power; if the relays 50 had been energised to permit door opening, they will again be energised.

Claims

- 11 - Claims 1. A system for controlling the operation of the doors of a

railway train, the system comprising a radio- frequency identification tag installed adjacent to each end of a platform, the tags being coded with different identification data; and the train having radio transmitter/receiver units to detect the tags, these units being mounted on the train in the vicinity of each door, and providing an electrical output signal to control opening of that door.
2. A system as claimed in claim 1 wherein the transmitter/receiver units are low power units, the radio power transmitted being no greater than 1 W.
3. A system as claimed in claim 1 or claim 2 wherein each tag is a passive device.
4. A system as claimed in any one of the preceding claims wherein the tags and the transmitter/receiver units operate in the frequency range encompassing UHF and microwaves.
5. A system as claimed in claim 4 wherein the tags and the transmitter/receiver units operate at a frequency in the range 860 MHz930 MHz.
6. A system as claimed in any one of the preceding claims wherein each tag transmits data by frequency modulation.
7. A system as claimed in any one of the preceding claims wherein each transmitter/receiver unit incorporates an integral antenna.

- 12 -
8. A system as claimed in any one of the preceding claims wherein each transmitter/receiver unit incorporates separate antennas for transmission and reception.
9. A system as claimed in any one of the preceding claims wherein each transmitter/receiver unit controls operation of a relay.
10. A system as claimed in any one of the preceding claims wherein at least one transmitter/receiver unit is provided on each side of each carriage.
11. A system for controlling the operation of the doors of a railway train, substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

15882 MdDe P T Mansfield

Chartered Patent Agent Agent for the Applicant