Patent Publication Number: US-8532842-B2

Title: System and method for remotely controlling rail vehicles

Description:
FIELD 
     The subject matter disclosed herein relates to remote control of a rail vehicle. 
     BACKGROUND 
     A rail vehicle, such as a locomotive that propels a group of rolling stock on a railroad track, is operated by a crew of multiple people. For example, a locomotive that is traveling on a main line railroad is typically operated by a crew of at least two people. In one example, a two-person crew includes an engineer and a conductor. The engineer drives the locomotive, for example by controlling speed and handling of the locomotive. On the other hand, the conductor manages operation of freight or passenger cars as well as various other types of railroad operations, such as track switching, and the like. 
     However, under some conditions, implementing a crew of two or more people to operate a locomotive is an inefficient use of labor resources. For example, during travel on the main line, the engineer performs a majority of the operational tasks while the conductor occasionally performs another railroad related task. In some cases, the engineer is prevented from performing tasks that are carried out by the conductor, because the engineer is required to have authority over the locomotive while on traveling on the main line by operating the controls, which are located in the locomotive cabin. Thus, the engineer is relegated to staying in the locomotive cabin while traveling on the main line, when they otherwise are capable of performing tasks carried out by the conductor. 
     BRIEF DESCRIPTION 
     Accordingly, to address the above issues, various embodiments of systems and methods for remotely controlling a rail vehicle are described herein. For example, in one embodiment, a remote operator control system comprises a communication link to send and receive rail vehicle information, an operator interface, and a controller. The controller is configured to send, through the communication link, a request to establish communication with a positive train control system on-board a selected rail vehicle based on an operating condition. The positive train control system is a system that monitors location and movement of the rail vehicle to enforce movement authorities and speed restrictions for a zone of track where the rail vehicle resides. In response to receiving confirmation of communication with the positive train control system, the control is configured to receive positive train control information for the selected rail vehicle through the communication link, and display the positive train control information for the selected rail vehicle on the operator interface. 
     In one example, the remote operator control system is a transportable apparatus that remains with a rail vehicle operator, such as an engineer of a locomotive. Since the remote operator control system receives positive train control information for the locomotive, the operator is able to stay informed of the positive train control information even when the engineer leaves the cabin of the locomotive. In other words, the engineer maintains authority of the locomotive even when the engineer leaves the cabin of the locomotive. Accordingly, the engineer is able to perform other rail road related tasks, such as tasks carried out by a conductor, while staying in compliance by maintaining authority of the locomotive. In this way, locomotive crews can be reduced and labor can be re-allocated, which results in cost reductions. 
     This brief description is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This brief description is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be better understood from reading the following description of non-limiting embodiments, with reference to the attached drawings, wherein below: 
         FIG. 1  is a schematic diagram of an example embodiment of a rail vehicle of the present disclosure. 
         FIG. 2  is a block diagram of an example embodiment of an operator interface of a remote control operator unit (ROCU) of the present disclosure. 
         FIG. 3  is a schematic diagram illustrating an example of a ROCU communicating with control systems of a rail vehicle to remotely control the rail vehicle. 
         FIG. 4  is a schematic diagram depicting an example of a rail vehicle being controlled by an energy management system (EMS) on a main line. 
         FIG. 5  is a schematic diagram depicting control of the rail vehicle of  FIG. 4  automatically switching from the EMS to a ROCU responsive to the rail vehicle switching from the main line to a rail yard. 
         FIG. 6  is a schematic diagram depicting an example of a rail vehicle being controlled by a ROCU in a rail yard. 
         FIG. 7  is a schematic diagram depicting control of the rail vehicle of  FIG. 6  automatically switching from the ROCU to an EMS responsive to the rail vehicle switching from the rail yard to a main line. 
         FIG. 8  is a schematic diagram depicting an example of a rail vehicle being controlled by an EMS. 
         FIG. 9  is a schematic diagram depicting control of the rail vehicle of  FIG. 8  being switched from the EMS to a ROCU responsive to an operator control command. 
         FIG. 10  is a schematic diagram depicting an example of a rail vehicle being controlled by a ROCU. 
         FIG. 11  is a schematic diagram depicting control of the rail vehicle of  FIG. 10  switching from the ROCU to an EMS response to an operator control command. 
         FIG. 12  is a flow diagram of an example embodiment of a method for of establishing a communications path between a ROCU and an on-board positive train control (PTC) system so that PTC information is received by the ROCU. 
         FIG. 13  is a flow diagram of an example embodiment of a method for switching control of a rail vehicle between an on-board EMS and a ROCU based on operating conditions. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure is directed to a remote control system that has communication paths that are integrated with other systems located on-board a rail vehicle so that the remote control system can receive information about the rail vehicle as well as provide control commands to operate the rail vehicle. In one example, as illustrated in  FIG. 1 , a remote operator control unit (ROCU) communicates with a positive train control (PTC) system that is located on-board a rail vehicle. The ROCU receives PTC information about the location of the rail vehicle and the travel path associated with the rail vehicle. The PTC information is displayed by an operator interface on the ROCU so that an operator of the rail vehicle can remain informed of the state of the rail vehicle location even when the operator is remotely located from the on-board PTC system. 
     As another example, the ROCU communicates with an energy management system (EMS) that is located on-board the rail vehicle. When in control of operation of the rail vehicle, the EMS provides control commands to the rail vehicle based on an operating state of the rail vehicle to increase or optimize efficiency of the rail vehicle (e.g., reduce fuel consumption) for a predefined trip. The communication path between the ROCU and the EMS enables an operator to switch control of the rail vehicle between the ROCU and the EMS as desired. For example, the operator can control operation of the rail vehicle manually through input to the operator interface of the ROCU. On the other hand, the operator can switch to the EMS for automated control of rail vehicle operation. In this manner, an operator is able to receive rail vehicle information and adjust control of rail vehicle operation to accommodate varying travel conditions even when the operator is remotely located from systems that are positioned on-board the rail vehicle. 
       FIG. 1  is a schematic diagram of an example embodiment of a vehicle or vehicle system, herein depicted as a rail vehicle  100 , configured to travel on a rail  102 . The rail vehicle  100  includes a propulsion system  104 . In one example, the propulsion system  104  includes an engine, such as diesel engine that combusts air and diesel fuel through compression ignition. In other non-limiting embodiments, the propulsion system  104  includes an engine that combusts fuel including gasoline, kerosene, biodiesel, or other petroleum distillates of similar density through compression ignition (or spark ignition). In one example, the rail vehicle  100  is a diesel-electric vehicle. For example, the propulsion system  104  is a diesel engine that generates a torque output that is converted to electricity by an alternator (not shown) for subsequent propagation to a variety of downstream electrical components. The alternator provides electrical power to a plurality of traction motors (not shown) to provide tractive power to propel the rail vehicle  100 . Correspondingly, the tractive motors provide regenerative braking capabilities to slow the rail vehicle during braking conditions. Moreover, the propulsion system  104  includes brakes (not shown), such as air brakes or friction brakes that are operable to slow the rail vehicle  100 . 
     The propulsion system  104  includes sensors  106  that measure operating parameters of the rail vehicle  100 . In one example, the sensors  106  measure engine operating parameters including, but not limited to, barometric air pressure, mass air pressure, ambient temperature, engine coolant temperature, engine speed, engine torque, air/fuel ratio, exhaust pressure, exhaust temperature, etc. In one example, the sensors  106  measure electrical operating parameters including, but not limited to, electrical output, horsepower, battery state of charge, traction motor speed, traction motor temperature, etc. In one example, the sensors  106  measure rail vehicle position parameters including, but not limited to, beginning of rail vehicle location, end of rail vehicle location, etc. It will be appreciated that the sensors  106  measures a suitable operating parameter or may be used to determine a suitable operating parameter or operating condition of the rail vehicle  100 . 
     The propulsion system  104  includes actuators  108 , the state of which is varied to adjust operation of the propulsion system  104 . In one example, actuators  108  adjust engine operation. Example actuators that are adjusted to control engine operation include cylinder valves, fuel injectors, throttle, etc. In one example, actuators  108  adjust electrical components. Example electrical components that are adjusted to control operation of the rail vehicle include the alternator, traction motors, etc. It will be appreciated that the actuators  108  include a suitable component for adjusting operation of the rail vehicle  100 . 
     A positive train control (PTC) system  110  is positioned in a cabin  101  of the rail vehicle system  100  to monitor the location and movement of the rail vehicle  100 . The PTC system  110  includes a communication link  112 , a PTC controller  114 , travel information  116 , and a PTC display  122 . 
     The communication link  112  communicates with a dispatch at a remote office  124 , wayside devices  126 , and a remote operator control unit  142  to send and receive travel information  116 . In particular, the PTC system  110  sends rail vehicle state and location information  118  to the remote office  124 . Correspondingly, the PTC system  110  receives location, track, and travel restriction information  120  from the remote office  124 . In one example, the communication link  112  includes a radio transceiver. The radio transceiver operates at a 220 MHz radio frequency that allows for a range of approximately 20-30 miles. In one example, the communication link includes a global positioning system (GPS) device to determine a location of the rail vehicle  100  that is sent to the remote office  124  and/or the wayside device  126 . In one example, the PTC system  110  is capable of operating in either dark (non-signaled) or signaled territory by employing GPS navigation to track the location of the rail vehicle  100 . 
     In some cases, the remote office  124  relays information through a base station or the wayside device  126  to the communication link  112 . The base stations and/or wayside devices are positioned at intervals within the broadcast range of the communication link  112  to stay in communication during travel. In one example, a base station is approximately a 100-foot tall tower that includes antennas and radios with multi-channel receivers that send and receive radio signal up and down the length of the rail road track. If there are several tracks in an area, the base station and/or wayside device  126  can include a bank of radio channels that different rail vehicles can log onto and communicate with during traveling throughout a zone. In some cases, the wayside devices  126  have an antennae with a much shorter length of frequency range and can either communicate directly to the communication link  112  or through the base station and then to the rail vehicle  100 . In some cases, the communication link  112  receives speed restrictions generated from the remote office  124  and then communicate in signal territory to the wayside device  126  to coordinate movement of the rail vehicle  100 . 
     The PTC controller  114  manages operation of the PTC system  110 . In one example, the PTC controller  114  includes a computer system including a processor and a non-transitive storage device that holds instructions that when executed perform operations to control the PTC system  110 . For example, the PTC controller  114  enforces travel restrictions including movement authorities that prevent unwarranted movement of the rail vehicle  100 . In some embodiments, the PTC system  110  controls operation of the rail vehicle to comply with the movement authorities. Based on the received travel information  116 , the PTC controller  114  determines the location of the locomotive and how fast it can travel based on the travel restrictions, and determines if movement enforcement is performed to adjust the speed of the rail vehicle  100 . In this way, rail vehicle collisions, over speed derailments, incursions into work zones, and/or travel through an improperly positioned switch can be reduced or prevented. As an example, the PTC system  110  provides commands to the propulsion system  104  to slow or stop the rail vehicle  100  in order to comply with a movement authority. 
     The travel information  116  is organized into a database that is stored in a storage device of the PTC controller  114 . In one example, the database houses rail road track information that is updated by the remote office  124  through the communication link  112 . The travel information  116  includes rail vehicle location information  118 . In one example, the rail vehicle location information  118  is determined from GPS information of the communication link  112 . In one example the rail vehicle location information  118  is determined from sensors  106  such as beginning of rail vehicle location and end of rail vehicle location sensors. In one example, rail vehicle location information  118  is determined through communication with the wayside devices  126 . The travel information  116  includes travel restriction information  120 . The travel restriction information  120  includes movement authorities and speed limits which can be travel zone or track dependent. The travel restriction information  120  can take into account rail vehicle state information such as length, weight, height, etc. 
     The PTC display  122  is positioned in the cabin  101  of the rail vehicle  100  to display travel information  116  as well as other rail vehicle state and control information to the operator. The PTC display  122  is dedicated to displaying PTC information separate or independent of the remote operator control unit  142  including an operator interface  146 . 
     An energy management system (EMS)  128  is positioned in the cabin  101  of the rail vehicle system  100  to controlling speed of the rail vehicle  100  to increase operating efficiency by reducing fuel usage. The EMS  128  includes a communication link  130 , an EMS controller  132 , trip plan information  134 , and an EMS display  140 . 
     The communication link  130  communicates with the PTC system  110  and the remote operator control unit  142  to send and receive rail vehicle state and location information, travel information, and other suitable information. In one example the communication link  130  receives rail vehicle manifests, temporary slow orders, and/or rail road track database updates. Furthermore, the communication link  130  receives signals from the sensors  106  and sends command signals to the actuators  108  to adjust operation of the propulsion system  104 . In one example, the communication link  130  includes a radio transceiver that enables wireless communication. In particular, the communication link sends and/or receives multiple messages per second to enable communication. 
     The EMS controller  132  manages operation of the EMS system  128 . In one example, the EMS controller  132  includes a computer system including a processor and a non-transitive storage device that holds instructions that when executed perform operations to control the EMS system  128 . For example, the EMS controller  132  evaluates predefined travel paths or routes for fuel savings opportunities and plots rail vehicle speed based on operating conditions. Furthermore, the EMS controller  132  provides automated closed loop control of the actuators  108  of the propulsion system  104 . In one example the closed loop control is based on a location determination, speed regulation, and/or rail vehicle state. The closed loop control reduces unnecessary braking and automatically operates the throttle based on feedback from speed and acceleration data received from the sensors  106 . 
     The trip plan information  134  is organized into a database that is stored in a storage device of the EMS controller  132 . In one example, the database houses a fuel usage profile, rail vehicle estimator/corrections, and/or rail vehicle handling algorithms. The trip plan information  134  provides a plan of operation for the rail vehicle to increase efficiency that is based on rail vehicle state information  136  and travel information  138 . In one example, the rail vehicle state information  136  includes rail vehicle velocity and rail vehicle characteristics that are used for adjusting speed and time recovery. It will be appreciated that rail vehicle state information  136  includes suitable information determined from signals received from the sensors  106 , other controllers, and/or GPS information. In one example, the travel information  138  includes trip time, rail vehicle location, and rail road track information, such as anticipated grades, movement authorities, and speed restrictions. In some embodiments, the EMS  128  receives travel information from the PTC system  110 . 
     The EMS display  140  is positioned in the cabin  101  of the rail vehicle  100  to display the trip plan information  134  as well as other rail vehicle state and control information to the operator. In one example, the EMS display  140  presents rail vehicle status information and a rolling map that includes rail road track zones and the like. The EMS display  140  is dedicated to displaying EMS information separate or independent of the remote operator control unit  142  including the operator interface  146 . The EMS display  140  is repeatedly updated to provide the operator with a tool to manage the rail vehicle trip by showing trades between trip time and fuel used, as opposed to operating at or near the speed limit all the time. 
     The remote operator control unit (ROCU) or system  142  provides an operator of the rail vehicle  100  with information received from the PTC system  110  and the EMS  128 . Furthermore, the ROCU  142  provides the operator with manual control capability to control operation of the rail vehicle  100  from a location that is remote from the cabin  101  of the rail vehicle  100 . The ROCU  142  enables the operator to remotely switch between manual operation of the rail vehicle and automated operation of the rail vehicle through control by the EMS  128 . In one example, the ROCU  142  is a transportable apparatus that enables the operator to maintain control authority over a rail vehicle, even when the operator is remotely located from the cabin of the rail vehicle. The ROCU  142  includes a communication link  148 , an operator interface  146 , and a ROCU controller  150 . 
     The communication link  148  provides integrated communication paths to communicate with the PTC system  110  and the EMS  128 . Through the integrated communication paths, the communication link  148  is able to send and/receive rail vehicle state  136  and location  118  information from the PTC system  110  and/or the EMS  128 . Furthermore, the communication link  148  communicates with the sensors  106  to receive rail vehicle state information and with the actuators  108  to send control commands to adjust operation of the rail vehicle  100 . In one example, the communication link  148  includes a radio transceiver to enable wireless communication. 
     The operator interface  146  includes a display  202  (shown in  FIG. 2 ) to display information received from the PTC system  110  and the EMS  128  as well as an operator input  206  (shown in  FIG. 2 ) that enables the operator to input control commands to manually control operation of the rail vehicle  100  as well as switch to and from automated control by the EMS  128 . 
     The ROCU controller  150  manages operation of the ROCU  142 . In one example, the ROCU controller  150  includes a computer system including a processor and a non-transitive storage device that holds instructions that when executed perform operations to control the ROCU  142 . For example, the ROCU controller  150  provides control command manually input by the operator to adjust the actuators  108  of the propulsion system  104 . Furthermore the ROCU controller  150  provides control commands to the EMS  128  to transfer control to the ROCU  142  for manual control of operation of the rail vehicle  100  or transfer control to the EMS  128  for automated control of operation of the rail vehicle  100 . In some cases, control of operation of the rail vehicle is automatically transferred between the ROCU  142  and the EMS  128  based on operating conditions of the rail vehicle  100 . 
       FIG. 2  is a block diagram of an example embodiment of the operator interface  146  of the ROCU  142 . As discussed above, the operator interface  146  includes a display  202  that presents rail vehicle system information to the operator as well an operator input  206  to provide control command input to manually control operation the rail vehicle  100 . Furthermore, the operator input  206  enables the operator to input control commands to switch between manual control of operation of the rail vehicle  100  and automated control of operation of the rail vehicle  100  by the EMS  128 . 
     The display  202  presents a rolling map  204  as well as system information received from other system of the rail vehicle  100 . The rolling map  204  provides an indication of the location of the rail vehicle  100  to the operator. The rolling map  204  is annotated with various rail vehicle location information. For example the rolling map  204  includes a beginning of rail vehicle location, an end of rail vehicle location, rail vehicle length, rail road track zone, mile post markers, wayside device location, GPS location, etc. Furthermore, the rolling map  204  is annotated with movement authority regulations and speed restrictions. 
     Furthermore, the display  202  presents information received from the PTC system  110 . In particular, the display  202  presents travel information  116  that includes rail vehicle location information  118  and travel restriction information  120 . The display  202  presents information received from the EMS  128 . In particular, the display  202  presents trip planner information  134  that includes rail vehicle state information  136  and travel information  138 . It will be appreciated that the display  202  presents a suitable information related to the state and/or location of the rail vehicle  100  that is receive from other systems of the rail vehicle  100 . In some cases, the display  202  presents information that is received directly from the wayside device  126  and/or the remote office  124 . 
     The operator input  206  enables the operator to provide control commands to control operation of the rail vehicle  100 . In one example, the operator input  206  includes buttons, switches, and the like that are physically actuated to provide input. In one example, the operator input  206  includes a touch sensitive display that senses touch input by the operator. The operator input  206  includes a speed control  208 . The speed control  208  initiate the sending of control commands to actuators  108  responsive to operator input that manually adjusts the speed of the rail vehicle  100 . In particular, the speed control  208  includes a throttle input  210 , a brake input  212 , and a reverse input  214 . The speed control  206  may provides speed adjustment in a suitable manner. 
     Furthermore, the operator input  206  includes a transfer control to EMS input  216  and a transfer control input from EMS input  218 . The transfer control to EMS input  216  initiates sending of control commands to the EMS  128  responsive to operator input to take control of operation of the rail vehicle  100  for automated control. The transfer control from the EMS input  218  initiates sending of control commands to the EMS  128  responsive to operator input to relinquish control of operation of the rail vehicle  100  to the ROCU  142  for manual control. 
     In some embodiments, the EMS  128  is a passive system that prompts the operator with suggested operating parameters to reducing fuel consumption and decrease braking In such embodiments, the display  202  presents an EMS prompted speed recommendation  220  that is updated based on operating conditions of the rail vehicle  100 . 
       FIG. 3  is a schematic diagram illustrating an example of a ROCU communicating with control systems (e.g., the PTC system  110  and the EMS  128 ) to remotely control the rail vehicle  100 . In some embodiments, the ROCU  142  temporarily resides in a ROCU cradle  302  that is positioned inside of the cabin  101  of the rail vehicle  100 . The ROCU cradle  302  provides various capabilities to the ROCU  142 . For example, the ROCU cradle  302  provides power charging capabilities to the ROCU  142 . The ROCU  142  is removable from the ROCU cradle  302  so that the operator can take the ROCU  142  from the cabin  101  of the rail vehicle  100  to perform various tasks and still receive rail vehicle state and location information as well as have authority over the rail vehicle  100 . 
     In some embodiments, the ROCU  142  is configured to automatically synchronize with other systems of the rail vehicle  100  in response to the ROCU  142  being removed from the ROCU cradle  302 . In one example, when the ROCU  142  is removed from the ROCU cradle  302 , communication is initiated between the ROCU  142  and the PTC system  110  as well as the EMS  128 . Correspondingly, the PTC system  110  and the EMS  128  send information to the ROCU  142  to be presented to the operator. In this manner, the operator may stay informed of rail vehicle state and location information, even when the operator leaves the cabin  101  of the rail vehicle  100 . 
     Additionally (or alternatively) the ROCU  142  proximal communication capabilities to selectively initiate synchronization with other systems of the rail vehicle  100 . In one example, the ROCU  142  includes an infrared (IR) port that can be used to initiate synchronization. In one example, the ROCU  142  includes a radio frequency identification (RFID) device that is used to detect proximity to the cabin  101  of the rail vehicle  100 , such that when the ROCU  142  leaves the cabin the RFID device detects the change in location and synchronization is initiated. It will be appreciated that various other technologies may be implemented to implement synchronization between the ROCU  142  and other systems of the rail vehicle  100 . 
     Furthermore, control commands can be sent from the ROCU  142  to the EMS  128  responsive to removal of the ROCU  142  from the ROCU cradle  302 . The control commands are sent through the established communication path to switch between manual control through the ROCU  142  and automated control through the EMS  128 . Further still, in one example, when the ROCU  142  is removed from the ROCU cradle  302 , communication is initiated between the ROCU  142  and the sensor  106  as well as the actuators  108 . In this manner, the operator may provide automated or manual control of the rail vehicle  100 , even when the operator leaves the cabin  101  of the rail vehicle  100 . 
     The ROCU  142  is configured to transfer control of operation of the rail vehicle  100  between the ROCU  142  and the EMS  128  based on different operating conditions.  FIGS. 4-11  depict different examples of operating conditions that elicit transfer of control between the ROCU  142  and the EMS  128 .  FIGS. 4-7  depict examples where control is automatically switched between the ROCU  142  and the EMS  128 .  FIGS. 8-11  depict examples where control is manually switched between the ROCU  142  and the EMS  128  in response to operator input to the ROCU  142 . 
       FIGS. 4 and 5  depict a first example where control of the rail vehicle is automatically switched based on an operating condition. In this example, the operating condition includes the rail vehicle crossing over from a rail road main line to a rail yard.  FIG. 4  depicts a rail vehicle that is being controlled by the EMS  128  while traveling on the main line. The EMS  128  provides rail vehicle control commands that increase efficiency of the rail vehicle by finding opportunities to adjust operation to reduce unwarranted braking and reduce fuel consumption.  FIG. 5  depicts the rail vehicle of  FIG. 4  crossing from the main line into a rail yard. Once in the rail yard, more flexible manual operation of the rail vehicle is prioritized over trip efficiency, since the rail vehicle can be stationary and start/stopped periodically. Accordingly, control of the rail vehicle is automatically transferred from the EMS  128  to the ROCU  142  in response to the rail vehicle crossing from the main line into the rail yard. Since operation of the rail vehicle is manual controlled by the operator through the ROCU  142 , the operator can position the rail vehicle as desired even when leaving the cabin of the rail vehicle. For example, the operator can manually control the rail vehicle when the operator is remotely located from the rail vehicle, such as when the operator is disconnecting a knuckle of a rail car on a different track in the rail yard to reconfigure the rolling stock. 
       FIGS. 6 and 7  depict another example where control of the rail vehicle is automatically switched based on an operating condition. In this example, the operating condition includes the rail vehicle crossing over from a rail yard onto a rail road main line.  FIG. 6  depicts a rail vehicle that is being controlled by the ROCU  142  in the rail yard. The ROCU  142  allows for more flexible manual control by the operator in order to configure the rail vehicle for storage or travel.  FIG. 7  depicts the rail vehicle of  FIG. 6  crossing from the rail yard to the main line. Once on the main line, increased speed and efficiency provided by automatic operation are prioritized over more flexible manual operation. Accordingly, control of the rail vehicle is automatically transferred from the ROCU  142  to the EMS  128  in response to the rail vehicle crossing from the rail yard to the main line. It will be appreciated that transfer of control of operation of the rail vehicle may be performed automatically in response to various other suitable operating conditions. Moreover, the ROCU  142  maintains supervisory control when the rail vehicle is being controlled by the EMS  128 . For example, the operator can manually command an adjustment in operation (e.g., a stop) when the EMS is in control of rail vehicle operation, and the EMS relinquishes control to comply with the manual command provided by the ROCU  142 . 
     Although the above examples describe scenarios where control of rail vehicle operation is switched automatically based on operating conditions, it will be appreciated that in some embodiments, an operator initiates the transfer of control between manually controlled operation and EMS controlled operation. In this way, the operator has authority over the rail vehicle including the EMS system through the ROCU. To further support such authority, in one example, transferring control includes confirmations or handshakes between systems (e.g., ROCU and EMS) to reduce the likelihood of unintended transfer of control of the rail vehicle. 
       FIGS. 8 and 9  depict a first example where control of the rail vehicle is manually switched based on operator input to the ROCU  142 .  FIG. 8  depicts an example of a rail vehicle being controlled by the EMS  128 . For example, the rail vehicle is traveling on a main line. For a suitable reason, the operator decides to switch from automatic to manual control. For example, the operator wants to stop the rail vehicle in order to switch a track. The operator provides an operator control command, such as depressing the transfer control from EMS input  218  on the ROCU  142 . As shown in FIG.  9 , control of the rail vehicle is transferred from the EMS  128  to the ROCU  142  in response to the operator control command. 
       FIGS. 10 and 11  depict another example where control of the rail vehicle is manually switched based on operator input to the ROCU  142 .  FIG. 10  depicts an example of a rail vehicle being controlled by the ROCU  142 . For example, the rail vehicle may be stopped on the main line while the operator is switching the track. Upon switching the track, the operator is ready to resume the run down the line. To operate the trip more efficiently, the operator provides an operator control command, such as depressing the transfer control to EMS input  216  on the ROCU  142 . As shown in  FIG. 11 , control of the rail vehicle is transferred from the ROCU  142  to the EMS  128  in response to the operator control command. As demonstrated in the above described examples, the ROCU  142  enables switching between manual and automatic control of the rail vehicle even when the operator is positioned remotely from the EMS  128 . 
       FIG. 12  is a flow diagram of an example embodiment of a method  1200  for of establishing a communications path between a ROCU and an on-board positive train control (PTC) system so that PTC information is received by the ROCU. In one example, the method  1200  is performed by the ROCU  142  to communicate with the PTC system  110 . At  1202 , the method includes determining operating conditions. Determining operating conditions includes determining an operating state of the ROCU  142 . For example, it can be determined whether or not the ROCU has established a communication path with other systems of a rail vehicle. In embodiments where the ROCU communicates with other systems based on whether or not the ROCU is positioned in a cradle, it can be determined whether or not the ROCU is positioned in a cradle. 
     At  1204 , the method includes determining if operating conditions are suitable for a communication link to be established between the ROCU  142  and the PTC system  110 . If operating conditions are suitable to establish a communication path between the ROCU and the PTC system, the method moves to  1206 . Otherwise, the method returns to  1202 . 
     At  1206 , the method includes sending a request to establish a communication path with a PTC system for a selected rail vehicle. In some cases, a plurality of different rail vehicle may be in communication range of the ROCU, such as in a rail yard. Accordingly, the request includes a rail vehicle identifier that indicates the selected rail vehicle. 
     At  1208 , the method includes determining if a connection confirmation has been received from the PTC system of the selected rail vehicle. If it is determined that the PTC has confirmed connection with the ROCU, the method moves to  1210 . Otherwise, the method returns to  1208 . 
     At  1210 , the method includes receiving PTC messages or information from the PTC system for the selected rail vehicle. As discussed above, the PTC information includes rail vehicle state and location information. Furthermore, the PTC information includes track condition, movement authority, and speed restriction information. In some cases the PTC information may be information that is sent from a remote office that is relayed through the PTC system. 
     At  1212 , the method includes displaying the received PTC messages or information on a display of the ROCU. In one example, PTC information is presented on display  202  of ROCU  142 . 
     By establishing a communication path between a ROCU and a PTC system of a selected rail vehicle, an operator may view PTC information for the selected rail vehicle on a display of the ROCU, even when the operator is located remotely from a cabin of the rail vehicle where the PTC system is located. Moreover, since the operator is able to have the PTC information on their person, the operator is able to maintain authority of the rail vehicle even when the operator leaves the cabin. Accordingly, the operator is able to perform tasks that they would otherwise not be able to perform, such as tasks performed by a conductor. In this way, an operator is able to perform more tasked while being informed of PTC information for a rail vehicle. This enables a single-person crew to operate a rail vehicle on the main line with PTC technology implemented. Moreover, this may allow for a reduction or re-allocation of labor to other tasks, rail vehicles, etc. that results in cost savings. 
     Furthermore, since the ROCU is a portable apparatus, the ROCU can establish communication paths with different PTC systems for different rail vehicles. This can be beneficial in situations where a plurality of rail vehicles is located in a proximity to one another, such as in a rail yard. In this way, an operator may be informed of PTC information for different rail vehicles and perform tasks related to the different rail vehicles without having to enter the cabin of each of the rail vehicles. 
     Note the above method is applicable to establishing communication paths between the ROCU and other systems of a rail vehicle. For example, the above method may be performed to establish communication between the ROCU and an EMS of a rail vehicle. 
       FIG. 13  is a flow diagram of an example embodiment of a method  1300  for switching control of a rail vehicle between an on-board EMS of the rail vehicle and a ROCU based on operating conditions. In one example, the method is performed by the ROCU  142 , which sends control commands to EMS  128 . 
     At  1302 , the method includes determining operating conditions. Determining operating conditions includes determining rail vehicle state and location based on information received from other systems of the rail vehicle that are in communication with the ROCU. Determining operating conditions includes determining which system is controlling the rail vehicle. For example, the rail vehicle may be manually controlled by an operator in the cabin using rail vehicle controls. As another example, the rail vehicle may be automatically controlled by the on-board EMS. As yet another example, the rail vehicle may be manually controlled by an operator that is located remotely from the cabin of the rail vehicle through the ROCU. 
     At  1304 , the method includes determining if the rail vehicle is under automatic EMS control. If the EMS is controlling operation of the rail vehicle, the method moves to  1306 . Otherwise, the method moves to  1312 . 
     At  1306 , the method includes determining if an operator control command has been received by the ROCU commanding control of the rail vehicle be transferred from the EMS to the ROCU. If it is determined that the operator control command has been received, the method moves to  1310 . Otherwise, the method moves to  1308 . 
     At  1308 , the method includes determining if the rail vehicle has entered a rail yard. If it is determined that the rail vehicle has entered the rail yard, the method moves to  1310 . Otherwise, the method returns to other operations. 
     At  1310 , the method includes transferring control of the rail vehicle from the EMS to the ROCU. In one example, the ROCU sends a command to the EMS to relinquish control of the rail vehicle to the ROCU. Control of the rail vehicle is transferred from the EMS to the ROCU in response to various operating conditions. As particular examples, control is transferred from the EMS to the ROCU in response to receiving an operator control command or crossing from a main line into a rail yard. 
     At  1312 , the method includes determining if the rail vehicle is under manual ROCU control. For example, the operator manually provides input to an operator interface of the ROCU to control operation of the rail vehicle. If it is determined that the rail vehicle is under manual ROCU control, the method moves to  1314 . Otherwise, the method returns to other operations. 
     At  1314 , the method includes determining if an operator control command has been received by the ROCU that commands control of the rail vehicle be transferred from the ROCU to the EMS. If it is determined that the operator control command has been received, the method moves to  1318 . Otherwise, the method moves to  1316 . 
     At  1316 , the method includes determining if the rail vehicle has exited a rail yard. If the rail vehicle has exited the rail yard, the method moves to  1318 . Otherwise, the method returns to other operations. 
     At  1318 , the method includes transferring control of the rail vehicle from the ROCU to the EMS. In one example, the ROCU sends a command to the EMS to take control of the rail vehicle from the ROCU. Control of the rail vehicle is transferred from the ROCU to the EMS in response to various operating conditions. As particular examples, control is transferred from the ROCU to the EMS in response to receiving an operator control command or crossing from a rail yard onto a main line. It will be appreciated that automatically switching between ROCU and EMS control in response to crossing between a main line and a rail yard are merely examples. Moreover, control of the rail vehicle can be automatically switched between the ROCU and the EMS in response to entering or exiting a suitable designated rail road track zone. 
     By switching control of a rail vehicle between manual control through the ROCU and automatic control through the EMS, a rail vehicle can be flexibly controlled from a remote location, such as when organizing rail vehicles in a rail yard, as wells as controlled with increased efficiency at track speeds when operating on a main line rail road track. The above method enables operation of a rail vehicle by a single-person crew under varying operating conditions, which allows for a re-allocation of labor resulting in increased cost savings. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable a person of ordinary skill in the relevant art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.