Patent Publication Number: US-2013240677-A1

Title: Automatic end-of-train detection system

Description:
FIELD OF THE INVENTION 
     Aspects of this invention relate to an automatic end-of-train detection system that can inform the train driver and the operations control center that the length of the train is safe and secure. 
     BACKGROUND OF THE INVENTION 
     One of the challenges associated with rail transportation is the constant need to increase the cargos being carried, together with the need for rapid transportation. Consequently, modern railway trains tend to consist of large numbers of railcars carrying heavy working cargoes and traveling at high speeds. 
     Much of the risk associated with this type of transportation arises precisely from the control of these trains, in terms of their displacement logistics within the rail network, driving individual trains, or handling emergency situations. 
     One of the known ways of controlling railway trains is the use of telemetric equipment that checks the physical integrity of the train and performs supplementary functions related to detecting emergencies and controlling train movements. 
     Control equipment such as that mentioned above is already known, for example, in documents DE 4235256, ES 2 280 893, U.S. Pat. No. 7,222,003, U.S. Pat. No. 7,684,905 and WO 2009/089492. 
     Document DE 4235256 discloses an end-of-train monitoring system that is known in the state of the art. Designed to prevent accidents, caused by railcars slipping loose from their couplings, this system comprises transmitters at the head and tail of the train that send signals to a monitoring facility that compares the collected information with theoretical data in order to check the position of the train. 
     Document ES 2 280 893 describes a train integrity control method that consists of the transmission of a first signal representing the head of the train running through a checkpoint, a transmission of a second signal representing the end of the train running through the checkpoint, and the use of signals by a logic device that ascertains whether the entire train has passed the checkpoint. 
     The document U.S. Pat. No. 7,222,003 describes a method and a computer program for monitoring the integrity of a railway train and determining the movement of the train as it passes through a plurality of virtual blocks defined by wireless transmission stations along its route. This method consists of collecting data from a location at the head of the train and collecting data from a location at the end of train, with the data collected at the head of the train being of the same type as the data collected at the end of the train, processing the data collected at the head of the train and the end of the train in order to determine whether the train has run through one of the virtual blocks. The data collected at the head and tail of the train are processed through a set of rules stored in a database and retrieved by the processing unit. 
     The U.S. Pat. No. 7,684,905 document describes a system and method of ascertaining train integrity that uses train presence detection data and odometer data, processing this information in order to calculate the distance covered by the train and estimate its length, transmitting information indicating that the train is complete when the calculated length of the train is longer than the predetermined length of the train less the length of a railcar. 
     The monitoring and control systems described above are based on processing information or data taken from a location at the head of the train and a location at the end of the train, involving comparisons with pre-known theoretical parameters or determinations derived from pre-determined relational rules. 
     Thus, the known systems consist of dedicated processing units that conduct the comparisons and calculations needed by the system, with some systems even requiring specific databases or memories to store the collected data and the set of rules used in order to determine the integrity of the train. 
     All these processing and storage requirements influence the size of the onboard equipment, with the energy source necessarily being large enough to power the functioning of such highly complex equipment. 
     There is consequently a need for a simpler, lower-cost solution that allows railway train integrity to be monitored and controlled without heavy data processing. 
     Purposes of the Invention 
     Pursuant to the matters set forth above, one of the purposes of this invention is to provide an end-of-train detection system that offers a simpler and lower-cost solution for controlling railway train integrity. 
     Another purpose of this invention is to provide an end-of-train detection system that is simple to build, with easy installation and maintenance. 
     SUMMARY OF THE INVENTION 
     Aspects of the present invention attain the purposes set forth above through an end-of-train detection system for a railway train with a final railcar that passes over a rail in the rail network, with the detection system consisting of: 
     A first module installed on the final railcar comprised of a transmitter that is activated when a condition indicating the pass-through movement of the last railcar is present and that continues to transmit as long as the condition persists; and 
     A second module  5  installed on at least one fixed station installed close to the rail that is comprised of a receiver that receives the signal transmitted by the transmitter of the first module and sends a message indicating the pass-through movement of the final railcar to the railway train driver. 
     The message sent by the second module to the railway train driver is preferably a voice message. 
     In a preferred embodiment of this invention, the second module can also send a message indicating the pass-through movement of the last railcar to a remote facility of the railway train. 
     Still in the preferred embodiment of this invention, the railway train comprises a braking system with general piping, and the first module comprises the pressure transducer that activates the transmitter when the pressure in the general piping is equal to or greater than a pre-defined pressure of the braking system. Preferably, the first module is affixed to the general piping through an F type nozzle connector, being attached to the railcar by a chain and tetra-key padlock for better asset security. 
     The first module preferably comprises a compact box holding the transmitter, the pressure transducer and an independent power source, with the power source being a battery and the transmitter a digital radio. In this configuration, the compact box measures 40×40 mm and the first module weighs some 30 g. 
     The second module preferably comprises a digital radio receiver installed on a compact box, with the compact box measuring 50×40 mm and the second module weighing some 30 g. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The Figures show: 
       FIG.  1 — FIG. 1  illustrates schematic view of a railway train where the system of the present invention may be installed; 
       FIG.  2 — FIG. 2  illustrates one of the modules comprising the detection system addressed by an example materialization of this invention; 
       FIG.  3 — FIG. 3  illustrates another of the modules comprising the detection system addressed by an example materialization of this invention. 
       FIG.  4 — FIG. 4  illustrates a flow chart of a detection method according to various aspects of the current invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     This invention will be described in greater detail below, based on the examples of execution shown in the drawings. 
       FIG. 1  shows a schematic drawing of a railway train  1  traveling along the track  2  of a rail network. 
     The train  1  comprises at least one locomotive coupled to a plurality of railcars, with the plurality of railcars ending with a final railcar  3 . 
     As better illustrated in  FIG. 2 , the detection system addressed by this invention comprises a first module  4 , which is installed on the final railcar  3  in order to emit the signal indicating the pass-through movement of the final railcar  3  over a specific point on the rail network. 
     Thus, the first module  4  comprises a transmitter that is activated when a condition indicating the pass-through movement of the last railcar is present and that continues to transmit as long as the pass-through movement condition remains present. 
     A second module  5  of the system of the present invention is planned at fixed stations  6  arrayed along the rail network, close to the track  2 . The second module  5  comprises a receiver that receives the signal emitted by the first module  4  and a transmitter in order to send a message indicating the pass-through movement of the final railcar to the train driver. 
     In order to detect whether the entire length of the train has passed through safely and reliably in a simple and non-complex manner, in the preferred embodiment of this invention, the condition indicating the pass-through movement of the final railcar  3  is given by the pressure of the general piping of the braking system of the railway train. 
     As is known to experts in the state of the art, a train braking system consists of general piping running through the train, generally comprised by piping that carries compressed air to the braking system of the entire train. Thus, when the brake is applied, there is a pressure drop in the general piping, and when the brake is released, there is a pressure surge in the piping, until the pressures are equalized throughout the entire braking system. 
     Thus, in the preferred embodiment of this invention, the first module  4  comprises the pressure transducer that activates the transmitter when the pressure of the general piping is equal to or greater than a pre-defined pressure value corresponding to the equalized pressure of the braking system, for sending messages during checks. 
     In other words, when the train is passing over the device, the pressure in the general piping activates the transmitter that then transmits the signal indicating the pass-through movement. On the other hand, when the train is braking or halted, the pressure in the piping general remains below the level required to activate the transmitter and no signal indicating the pass-through movement is sent. 
     Preferably, the first module  4  comprises a compact box holding the transmitter, the pressure transducer and an independent power source for them both. As better illustrated in  FIG. 2 , this box is preferably installed on the general piping hose nozzle on the final railcar  3 , measuring 40×40 mm and weighing approximately 30 g. 
     Due to its small size and light weight, module  4  may be installed in an extremely simple and low-cost manner, such as on the general piping through an F type nozzle connector, for example, being attached to the railcar by a chain and tetra-key padlock for better asset security. 
     Installation directly on the general piping offers the additional advantage of allowing the module to be handled easily, for simpler installation and maintenance. 
     Still in the preferred embodiment of this invention, the transmitter is a radio frequency transmitter, such as a digital radio, for example, and the power source consists of lithium batteries. 
     As better illustrated in  FIG. 3 , the second module  5  is also a compact component, preferably installed on components already in place in the rail network  6 . Thus, in the preferred embodiment, the module comprises a radio frequency receiver such as a digital radio receiver for example, installed on a compact box measuring 50×40 mm, with the weight of the complete module not exceeding some 30 g. 
     The second module  5  receives the signal transmitted by the first module  4  and transmits a message to the train driver advising that the length of the train has passed over the point on the rails where the second module  5  is installed. 
     This message may be a voice message, for example, advising the train driver of the location of the point where the module is installed. An example this message would be: “End of train checked at kilometer xxx+xxx, pressure xx psi, fixed station xxx”. 
     In the preferred embodiment of this invention, module  5  can also send a message to a remote location along the segment of the rail network where it is installed, such as an operations control center for example. This message could be sent by satellite, indicating the exact place and time of the end-of-train pass-through movement detection. 
     It must be understood that the description presented above is based on a preferred materialization of the system addressed by this invention, with the real scope of the purpose of the Invention being defined in the Claims appended below.