Rail safety system

Abstract

A system which can easily and cheaply be installed to an existing rail infrastructure is disclosed which seeks to avoid the likelihood of train collisions. Each train travelling on a network is provided with a means for determining its own position (such as a GPS receiver) and a means for communicating with a central controller. The train's position is communicated to the central controller and the central controller uses this information to work out where each train is located on the network. Velocity and acceleration information are obtained by monitoring the train's position over time and predictions are made as to the future position of each of the trains on the network. If the future position of any of the trains is determined to be in a range which at least partially overlaps a range of future positions for another train then a collision warning is sent to one or both trains. This warning could trigger the train to stop automatically or for the driver to apply the breaks. Successive re-start signals are then sent so that the trains may continue on their journey without likelihood of collision.

1 . A method of determining if a train collision is possible, said method comprising the steps of: 
 obtaining data relating to the position of a train;    transmitting said data to a controller;    receiving said data at said controller;    performing a calculation at said controller using said data to predict a position of said train at a future time; and    using said predicted future position to determine whether any action needs to be taken.    
     
     
         2 . A method according to  claim 1 , wherein said calculation includes deriving differenced position vectors from said position data, said differenced position vectors having vector coordinates representing the difference between two consecutive coordinates in a vector of said position data.  
     
     
         3 . A method according to  claim 1  or  2 , wherein said calculation includes referring to a database of stored data relating to previous train journeys and identifying in said database vectors similar to a present journey vector, wherein said present journey vector is either said position data or differenced position vectors derived from said position data, said differenced position vectors having vector coordinates representing the difference between two consecutive coordinates in a vector of said position data.  
     
     
         4 . A method according to  claim 3 , wherein said database is a database of stored differenced position vectors.  
     
     
         5 . A method according to  claim 3 , wherein said database is a database of stored position vectors.  
     
     
         6 . A method according to any one of  claims 3  to  5  wherein said step of identifying similar vectors comprises evaluating whether the magnitude of a further vector obtained by subtracting a potentially similar vector in said database from said present journey vector is less than some prescribed positive number.  
     
     
         7 . A method according to any one of claims  3 - 6 , wherein said calculation includes extracting from said database predictive data, said predictive data being data recorded a particular period of time after said data identified as similar.  
     
     
         8 . A method according to  claim 7 , further comprising the step of adding the same number to each coordinate of said extracted predictive data vector so as to translate it by the amount of the number added.  
     
     
         9 . A method according to  claim 8 , wherein said number added corresponds to the current train position.  
     
     
         10 . A method according to any one of  claims 7  to  9 , wherein a set of predictive data is extracted, said set having a maximum value and a minimum value for any given particular period of time.  
     
     
         11 . A method according to  claim 10 , wherein said minimum and maximum values represent a range of possible train positions at said future time.  
     
     
         12 . A method according to any preceding claim, wherein said steps of obtaining data relating to the position of the train and transmitting said data to said controller are carried out a plurality of times for a plurality of respective trains and said controller determines if a collision is possible based on a prediction of a future position of said plurality of trains.  
     
     
         13 . A method according to  claim 12 , wherein said step of predicting a future train position is a step in which a plurality of intervals of future possible train positions for a plurality of respective trains is predicted in accordance with the method of  claim 8;  and 
 said step of determining if a collision is possible comprises determining whether at least some of said plurality of predicted intervals of possible train positions for said plurality of trains overlap.  
 
     
     
         14 . A method according to any preceding claim, further comprising the step of: 
 transmitting a warning signal to said train if it is determined that a collision is possible.    
     
     
         15 . A method according to any preceding claim, said method further comprising: 
 transmitting a stop message to said train if it is determined that a collision is possible.    
     
     
         16 . A method according to  claim 15 , further comprising the step of: 
 automatically stopping said train when said stop message is received from said controller.    
     
     
         17 . A method according to any preceding claim, wherein said step of determining a position of the train uses signals transmitted from GPS satellites.  
     
     
         18 . A method according to any preceding claim, wherein said transmitting and receiving steps are carried out using an electronic communications network.  
     
     
         19 . A method according to any preceding claim, wherein said transmitting and receiving steps are carried out using Internet protocols within a extranet structure.  
     
     
         20 . A method according to any preceding claim, wherein said step of transmitting said data to said controller is carried out using a mobile telephone.  
     
     
         21 . A method according to any preceding claim, wherein said obtained data relating to a position of a train is converted to position data along a real line model.  
     
     
         22 . A method according to  claim 21 , wherein said calculation performed at said controller predicts a future position, or range of future positions, along said real line model.  
     
     
         23 . A method according to  claim 22 , wherein said predicted position, or said range of predicted positions, is converted to data representing a position, or range of positions, on said track network.  
     
     
         24 . Apparatus for determining the possibility of a train collision, said apparatus comprising first means situated on said train and second means situated remote from said train; 
 said first means comprising: 
 position determining means for determining the position of said train;  
 communication means operatively linked to said position determining means for transmitting the position determined by said position determining means; said second means comprising: 
 receiving means for receiving said determined position from said communication means;  
 prediction means for predicting a future position of said train based on said received determined position; and  
 collision determining means for determining whether a collision is possible based on the result of said prediction means.  
 
   
     
     
         25 . Apparatus according to  claim 24 , wherein said second means further comprises a database of stored data relating to previous train journeys.  
     
     
         26 . Apparatus according to  claim 25 , wherein said prediction means comprises: 
 identifying means for identifying stored data which is similar to said determined position or is similar to data derived from said determined position.    
     
     
         27 . Apparatus according to  claim 26 , wherein said prediction means further comprises: 
 extracting means for extracting predictive data, said predictive data having originally been obtained at a future time to said identifying stored data.    
     
     
         28 . Apparatus according to  claim 27 , wherein said extracting means is for extracting a set of predictive data, said set having a minimum and maximum value.  
     
     
         29 . Apparatus according to  claim 28 , wherein said set defines a range of predicted future positions for said train.  
     
     
         30 . Apparatus according to  claim 29 , wherein said collision determining means uses a plurality of said sets of predictive data obtained for different trains and determines a collision is possible when at least two of said sets overlap.  
     
     
         31 . Apparatus according to any one of  claims 24  to  30 , wherein said position determining means comprises a GPS receiver.  
     
     
         32 . Apparatus according to any one of  claims 24  to  31 , wherein said communication means comprises a mobile telephone.  
     
     
         33 . Apparatus according to any one of  claims 24  to  32 , wherein said communication means comprises a portable computer having a modem.  
     
     
         34 . Apparatus according to any one of  claims 24  to  33 , further comprising means at said second means for transmitting a message to said first means.  
     
     
         35 . Apparatus according to  claim 34 , wherein said message comprises a warning message.  
     
     
         36 . Apparatus according to  claim 34 , wherein said message comprises a stop message.  
     
     
         37 . Apparatus according to  claim 24  to  36 , further comprising means at said second means for transmitting a re-start signal when it is determined that it is safe for a stopped train to start.  
     
     
         38 . Apparatus according to  claim 37 , further comprising means at said first means for re-starting a stopped train upon receipt of a received re-start signal.  
     
     
         39 . Train safety means for use with the method according to any one of  claims 1  to  23 , said train safety means comprising: 
 position determining means;  
 communication means operatively linked to said position determining means for transmitting a position so determined.  
 
     
     
         40 . A controller for use with the method of any one of  claims 1  to  23 , said controller comprising: 
 receiving means for receiving data relating to a determined train position;  
 prediction means for predicting a future train position based on said received train position data; and  
 collision determining means for determining whether a collision is possible based on said predicted future position.  
 
     
     
         41 . Use of a mobile telephone for transmitting data relating to a determined position of a train and for receiving data relating to a possibility of a collision.  
     
     
         42 . Use of a computer system for receiving data relating to a determined position of a train, for predicting a future position of said train using said received positional data, for predicting the possibility of a collision based on said predicted future position and for transmitting messages to said train if the possibility of a collision is predicted.  
     
     
         43 . A memory means storing computer readable instructions which, when connected to a suitable computer, is operable to cause said computer to carry out the following method: 
 receive data from a plurality of trains, said data relating to a determined position of said respective train;    accessing a database available to said computer, said database containing information about the train network on which said train is located;    calculating, using said received position data and said network database, the position of each train on a track of said network;    predicting the position of each train at a point in time in the future; and    determining if a collision between two or more of said plurality of trains is possible using said predicted future positions.    
     
     
         44 . A method substantially as hereinbefore described with reference to any one of FIGS.  1  to  9  of the accompanying drawings.  
     
     
         45 . Apparatus constructed and arranged substantially as hereinbefore described with reference to any one of FIGS.  1  to  9  of the accompanying drawings.