TECHNICAL FIELD

[0001] The present disclosure relates to railroad vehicles. Specifically, the disclosure relates to railroad maintenance vehicles having a seat that moves at a generally constant speed relative to a fixed point outside of the railroad maintenance vehicle while the railroad maintenance vehicle repeatedly starts and stops.

BACKGROUND

[0002] Generally, a railroad track includes at least one pair of substantially parallel rails coupled to a plurality of laterally extending ties. Each tie is coupled to both of the rails by a metal tie plate and/or spring clips. The ties are disposed on a ballast bed. The ballast is a hard particulate material such as, but not limited to, gravel. Ties are generally made from either concrete or wood. The ballast filled space between ties is called a crib. Concrete ties are typically spaced about twenty-four inches apart, whereas wood ties are spaced about nineteen and a half inches apart.

[0003] During installation and maintenance, various operations must be performed at each tie location. For example, ballast must be "tamped," or compressed, to ensure that the ties, and therefore the rails, do not shift. A tamping device, known as a "tamper," typically consists of at least two pairs of work heads mounted on a motorized vehicle structured to travel on the rails. A work head includes a pair of elongated, vertically extending tools structured to move together in a pincer-like motion as well as being structured to move vertically. The tools, preferably, have two prongs spaced so that each prong may be disposed on opposite lateral sides of a rail. The work head further includes a vibration device structured to rapidly vibrate the tools. In this configuration, a work head may be disposed above a tie with one tool on either side of the tie. Further, the prongs of each tool are disposed on either sides of the rail. Thus, a tool prong is disposed above, and just outside, of each corner of the rail/tie interface. Typically, at least two work heads are used so that one work head may be placed over each rail, although one work head may be used in some embodiments.

[0004] Initially, the tools are generally vertical and parallel to each other. When actuated, the tool head moves vertically downward so that the tips of the tools, that is the tips of the prongs, are inserted into the ballast to a predetermined depth that is, preferably, below the bottom of the tie. The tools are then brought together in a pincer-like motion thereby compressing the ballast under the tie. Actuation of the vibration assembly further compresses the ballast under the tie. Once the tamping cycle is complete, the tools are returned to a substantially vertical orientation and lifted out of the ballast. This completes a single tamping operation, which typically lasts about three seconds.

[0005] This operation may then be repeated at the same location if desired ("double tamping"), or the operation can be performed after the machine is moved to a new work location. The act of advancing the tamper to the next work location is called "indexing." Indexing may be performed one tie at a time ("single tie space"), in which case every tie will be tamped. Alternatively, indexing may be performed several ties at a time, for example "double tie space" when the indexing is performed two ties at a time, "triple tie space" when the indexing is performed three ties at a time, etc. The tamper vehicle, as well as other rail installation and maintenance vehicles, typically locates the tie/rail interface by locating the tie plate that connects the rail to the tie, e.g. by utilizing a metal detector that travels beside the rail.

[0006] Conventional equipment performing track maintenance consists mostly of machines carrying one or two operators. These machines accelerate (under their own power), to the ties requiring work. As they approach the tie, they rapidly slow down to a stop, perform the required work, and index to the next tie to repeat the cycle. During this acceleration and deceleration, the operator is being pushed backward and forward by the dynamics of the machine he is riding.

[0007] One existing machine designed to alleviate the problem on the operator consists of splitting the machine in two segments: one half of the machine does the indexing and a first work function while the other half moves at a constant speed while sometimes performing a different work function. The operator sits on the continuous moving portion of the machines. This system is normally employed on large machines and works in a satisfactory manner, however, the system is very expensive and cumbersome. For example, two different machines and two drives are required, the system is not practical for smaller and lighter machines due to the additional weight required to achieve an effective tractive effort, and the system requires sophisticated electronics to control the motion of the two segments relative to each other, for example, to prevent the two segments from colliding and thus damaging each other and/or injuring an operator. [0008] Another existing machine designed to alleviate the problem involves an operator cabin mounted upon a moveable platform, as disclosed in U.S. Patent No. 8,025,013, which is incorporated herein by reference. The moveable platform moves backwards and forwards with respect to the rest of the machine in order to keep the operator cabin, which is mounted on the moveable platform, moving forward at a generally constant speed relative to a fixed point outside the rail vehicle. The constant forward motion that the operator experiences in the cabin relative to that fixed point tends to alleviate problems caused by the machine advancing along the railroad track and suddenly stopping. This machine effectively isolates the operator cabin from the rapid acceleration and deceleration of the main machine, but is expensive to implement and presents considerable safety risks. For example, a substantial amount of cabling is required to connect the operator cabin with the rest of the machine, and this cable is subject to large amounts of movement as the operator cabin rapidly moves back and forth. This cable must withstand all of the movement and still allow the machine to operate correctly. Because of the rapid movement of the cable, more expensive high flex cabling is needed to make the required connections between the operator cabin and the rest of the machine. Another difficulty with this system is that the moveable platform does not allow workers to safely enter or leave the cabin during the machine's operation. The door to the cabin rapidly moves back and forth relative to the rest of the machine as the platform moves, creating a high risk of serious injury for anyone attempting to enter or exit the cabin unless operation is completely stopped. A further difficulty with this machine is that, because the operator cabin is large and heavy, a relatively large amount of force is required to move the platform backward and forward. Therefore, the moveable platform concept is not easily retrofitted onto existing machines, and thus completely new machines are required, at substantial cost. Also, as the platform moves backward and forward, either the platform or the operator cabin may come into close proximity with other parts of the machine, creating a potentially dangerous situation where an individual's body part may become caught, leading to possible injury.

[0009] Additionally, the mechanism used to move the platform also presents challenges. Generally, the accelerometers or other navigation systems are used to track the movement of the machine itself as it advances along the railroad. Communication from the accelerometers or the navigation system allows the platform to move backward and forward in response to the movement of the machine. However, the accelerometers or navigation system generally require a minimum amount of force or movement in order to trigger the platform to move. The delay between the machine beginning to advance along the railroad and the platform moving to compensate for the machine may cause the platform movement to be out of sync with the machine, and therefore may somewhat reduce the effectiveness of the system.

SUMMARY

[0010] According to an embodiment of the present disclosure, a rail vehicle for traveling on a railroad is provided. The rail vehicle has a frame assembly, a cabin affixed to the frame assembly, and a moveable seat assembly within the cabin. The moveable seat assembly includes a control device, a movement device, and a seat, and the seat is configured to travel longitudinally forward and backward relative to the frame assembly. As the frame assembly moves forward intermittently, the movement device moves the seat such that the seat moves in the forward direction at a generally constant velocity relative to a fixed point outside the rail vehicle.

[0011] According to another embodiment of the present disclosure, a rail vehicle for performing at least one type of tamping operation is provided. The rail vehicle has a frame assembly with a plurality of rigid members and a plurality of wheels configured to engage a set of railroad tracks. A cabin is affixed to the frame assembly. The cabin includes a control device within the cabin, and a movement device coupled to the cabin floor and to a seat. The control device communicates with the movement device, so that as the frame assembly accelerates forward to a subsequent railroad tie to perform a tamping operation, the control device directs the movement device to move the seat rearward to at least partially offset the forward acceleration, such that the seat moves in the first direction at a generally constant velocity relative to a fixed point outside the rail vehicle.

[0012] According to another embodiment of the present disclosure, a method is provided for adjusting the position of a seat within a rail vehicle. The method comprises selecting a type of tamping operation from a set of tamping operations. The method further comprises generating movement data by measuring, with a tracking device, the movement of the rail vehicle during at least one cycle of the tamping operation, and communicating the movement data to a control device. The control device directs the movement device to move the seat so that the seat moves at a generally constant velocity relative to a fixed point outside the rail vehicle. [0013] These and other capabilities of the invention, along with the invention itself, will be more fully understood after a review of the following figures, detailed description, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a side view of a rail vehicle;

[0015] FIG. 2 is a perspective view of a moveable seat in the cabin of a rail vehicle; [0016] FIG. 3 is a perspective view of a moveable seat assembly; [0017] FIG. 4 is a side view of a moveable seat assembly;

[0018] FIG. 5 shows, in an enlarged scale, details of the moveable seat assembly.

[0019] While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

[0020] While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated. For purposes of the present detailed description, the singular includes the plural and vice versa (unless specifically disclaimed); the words "and" and "or" shall be both conjunctive and disjunctive; the word "all" means "any and all"; the word "any" means "any and all"; and the word "including" means "including without limitation." Additionally, the singular terms "a," "an," and "the" include plural referents unless context clearly indicates otherwise.

[0021] As used herein, a "frame assembly" means that the frame assembly moves as a unit relative to a fixed point and that the front of the frame assembly is at a fixed distance from the back of the frame assembly. That is, while the frame assembly may have two or more parts that are articulated relative to each other, the frame assembly does not have distinct units or segments structured to travel on a pair of rails. [0022] As used herein, "coupled" means a link between two or more elements, whether direct or indirect, so long as a link occurs. Unless otherwise noted, this does not include elements resting on, or supported by, a surface. For example, a seat in an automobile is coupled to the engine via the frame and other components. The seat is not, however, coupled to an adjacent automobile via the ground.

[0023] As used herein, "directly coupled" means that two elements are directly in contact with each other.

[0024] As used herein, "communicatively coupled" means that two components are able to be in communication with each other. The communication is preferably, but not limited to, electronic communication.

[0025] According to aspects of the present disclosure, a rail vehicle consists of a frame assembly and a cabin coupled thereto. The frame assembly generally houses the tools used for operating on a railroad track, as well as a propulsion device used to advance the rail vehicle along the railroad track. The cabin contains a moveable seat assembly therein, as well as controls for the rail vehicle. The moveable seat assembly includes a movement device, a control device, and a seat. An operator sits on the seat and controls the rail vehicle from within the cabin during a tamping or other operation. The movement device is configured to move the seat forward and backward relative to the cabin. That is, the movement device is able to move the seat within the cabin longitudinally towards the frame assembly and in the direction of the rail vehicle's movement along the railroad track; or longitudinally away from the frame assembly and opposite the direction of the rail vehicle's movement along the railroad track. The movement device generally includes at least one hydraulic cylinder, electric linear actuator, or other mechanism for moving the seat. The control device may be, but is not limited to, a programmable logic circuit or a computer. The rail vehicle may also contain a tracking device to record the generally linear movement of the rail vehicle along the railroad track.

[0026] The rail vehicle includes at least one tamping device configured to tamp the ballast at a railroad tie. As the rail vehicle accelerates along the railroad track towards a railroad tie, the movement device moves the seat longitudinally backward relative to the frame assembly, to at least partially offset the effect of the acceleration on an operator sitting in the seat. When the rail vehicle stops over a railroad tie and begins to tamp the ballast at that tie, the movement device begins to move the seat longitudinally forward relative to the frame assembly. Once the rail vehicle completes the tamping for that tie, the tamping device retracts and the rail vehicle begins to advance further along the railroad track. When this occurs, the movement device stops moving the seat forward relative to the frame assembly and begins to move the seat backwards. In this configuration, the operator sitting in the seat maintains a generally constant speed with respect to a fixed point outside of the rail vehicle, and is minimally affected by the repeated acceleration and deceleration of the rail vehicle.

[0027] FIG. 1 shows a rail vehicle (shown as a tamping machine) which includes a frame assembly 102, a propulsion device 104 structured to move the rail vehicle 100, a navigation system, at least one tamping device 106 structured to tamp railroad ties 103, and a cabin 108. The cabin 108 is coupled to the frame assembly 102 which includes a plurality of rigid frame members and a plurality of wheels 110 that are configured to travel on a railroad track 101. The rail vehicle 100 may also include a tracking device 112 that measures the general linear movement of the rail vehicle 100 along a railroad track 101 and communicates the information to a control device.

[0028] As is known in the art, the rail vehicle 100 moves over a pair of rails that comprise a railroad track 101. The pair of rails is disposed on a series of ties 103. These series of ties 103 are further disposed on a bed of ballast. The frame assembly 102 includes a plurality of rigid frame members and a plurality of wheels 108 that are configured to travel on the pair of rails.

[0029] The navigation system is structured to track the position of the rail vehicle 100 relative to a fixed location such as but not limited to a location on the ground, as well as the position of each tie. The navigation system is further structured to control the propulsion device 104 to effect the forward motion of the rail vehicle 100 and to stop the rail vehicle 100 when the at least one tamping device 106 is positioned over the tie to be tamped. That is, the navigation system includes, or communicates with, a tie detection system (not shown) as is known in the art.

[0030] The tracking device 112 may be, but is not limited to, an encoder wheel. If an encoder wheel is used, the motion of the rail vehicle 100 is measured in pulses per revolution. That is, the speed (rotation/time) for each revolution of the encoder wheel is tracked. While the rail vehicle 100 is moving forward, the encoder wheel turns in a counterclockwise motion, as viewed in FIG. 1. The speed of the rail vehicle 100, or "movement data," is collected either constantly (analog) or, more typically, many times each second (digital). That data is converted to an electronic signal which is communicated to the control device.

[0031] The cabin 108 is structured such that it remains stationary relative to the frame assembly 102 as the rail vehicle 100 moves along the railroad track 101. The configuration of the stationary cabin 108 on the rail vehicle 100 generally reduces the number of pinch points that exist outside of the cabin 108. Because the cabin 108 is itself not moving relative to the rest of the rail vehicle 100, no pinch points are created between the cabin 108 and the rail vehicle 100 that might be dangerous to anyone entering or exiting the cabin 108, or anyone outside of the cabin 108 on the ground.

[0032] As shown in FIG. 2, a seat 120 is located within a cabin 108. The seat 120 is capable of moving longitudinally forward (as shown by arrow Ai) and backward (as shown by arrow Bi) within the cabin 108. These directions are relative to the frame assembly 102. That is, movement longitudinally forward is towards the frame assembly 102 and in the direction of the rail vehicle 100's movement along the railroad track 101, and movement longitudinally backward is movement away from the frame assembly 102 and opposite the rail vehicle 100's movement along the railroad track 101. The cabin 108 also generally includes a roof 122, a plurality of roof support structures 124, a door 126 and at least one window 128. Other embodiments of the cabin 108 are contemplated wherein the plurality of roof support structures 124, the door 126, and the at least one window 128 are configured differently than shown in FIG. 2.

[0033] As can be seen from FIG. 2, the cabin 108 generally reduces the number of pinch points that are created. While the seat 120 moves within the cabin 108, a narrow area generally exists only in the forward position, where the footrest 140 of seat 120 may potentially be in close proximity with the roof support structure 124 located at that point, as well as any other operator controls that may exist there (not shown). As shown, there is generally room to the sides and behind the seat 120 that allow an individual to safely move throughout the cabin 108 without being in danger of having a body part become caught in a pinch point.

[0034] In FIG. 3 is shown a perspective view of the moveable seat assembly 130 that is located within the cabin 108. The moveable seat assembly 130 includes a movement device housing 132, movement device 134 (shown within the housing), a channel 136 defined within the movement device housing 132, a seat 120, a seat base 138, and a control device (not shown). The seat 120 is mounted upon the seat base 138, which is coupled to the movement device 134. The moveable seat assembly 130 also preferably includes a footrest 140 that is directly coupled to the seat base 138.

[0035] The movement device 134 is configured to receive commands from the control device. The movement device 134 is further configured to move the seat 120 longitudinally backwards and forwards with respect to the frame assembly 102 in response to commands received from the control device. As the seat 120 moves, it travels in the empty space in the movement device housing 132 defined by the channel 136.

[0036] The moveable seat assembly 130 may also further include a lock 142. The lock 142 is configured such that when the lock 142 is engaged, the movement device 134 will not move the seat 120 longitudinally within the channel 136 and the seat 120 will remain stationary inside the cabin 108 with respect to the frame assembly 102. The seat 120 may also include at least one armrest 144 and at least one armrest control 146 that the operator may utilize during operation of the rail vehicle 100.

[0037] FIG. 4 is a side view of the moveable seat assembly 130. As is shown, the movement device 134 is located within the movement device housing 132. The seat 120 is mounted upon a seat base 138. There is preferably a footrest 140 directly coupled to the seat base 138. The lock 142, at least one armrest 144, and at least one armrest control 146 are all shown.

[0038] FIG. 5 shows a detailed view of the moveable seat assembly 130. The moveable seat assembly 130 preferably includes a control device (not shown) used to control the movement device. The control device is preferably a programmable device such as, but not limited to, a programmable logic circuit or computer. However, the control device may not be located within the movement device housing 132. The control device may be placed elsewhere on the rail vehicle 120, so long as the control device is still able to control the movement device 134. The movement device 134 includes at least one actuator 150, which in some embodiments may be a hydraulic cylinder, electric linear actuator, or similar mechanism. When a hydraulic cylinder is used, the control device is communicatively coupled to at least one valve. The valve may be, but is not limited to, a servo valve or a proportional valve, and is coupled to a hydraulic cylinder. When a valve receives a signal from the control device, the valve causes the hydraulic cylinder to actuate either forward or backward with respect to the frame assembly 102. In embodiments that utilize an electric linear actuator, at least one electric linear actuator is communicatively coupled to the control device. When an electric linear actuator receives a signal from the control device, the electric linear actuator is caused to actuate forward or back with respect to the frame assembly 102.

[0039] In some embodiments, the at least one actuator 150 is coupled to a plurality of steel bearings 152. The plurality of steel bearings 152 is directly coupled to a seat base 138 which supports the seat 120. When the at least one actuator 150 receives a signal from the control device, the actuator is caused to move the plurality of steel bearings 152 forward or backward relative to the frame assembly 102, thus moving the seat 120 forward or backward. Again, as shown, the moveable seat assembly 130 preferably has a footrest 140 directly coupled to the seat base 138.

[0040] For the sake of the following discussion, the seat 120 will be described as having a forward position, a medial position, and a rearward position. It is understood that these positions are not fixed relative to the rail vehicle 100 or the cabin 108, but vary depending upon how far the rail vehicle 100 moves during each cycle as described below. It is also understood that the distance between the forward position and the rearward position is typically not the total amount of travel available to the seat 120. That is, the actuator is able to move the seat 120 further forward or backward than is required for a typical tamping operation.

[0041] Again, using a typical tamping operation as an example, the rail vehicle 100 will move rapidly forward, stop, tamp the ballast around and under a tie or set of ties 103, and then move rapidly forward again until the tamping device 106 is positioned over the next tie or set of ties 103. This cycle is repeated until all of the desired ties or sets of ties 103 have been tamped. In order for the movement device 134 to maintain the operator moving forward at a generally constant speed relative to a fixed point outside of the rail vehicle 100, the control device must move the seat 120 in different directions relative to the rail vehicle 100 depending upon the stage of the cycle. It is understood that a tamping cycle will be considered to start just as the tamping devices 106 have completed tamping a tie or set of ties 103 and have withdrawn to the retracted position.

[0042] At the beginning of a tamping operation, the rail vehicle 100 will either be positioned over the first tie or set of ties 103 to be tamped, or will need to advance along the railroad track 101 until it reaches the first tie or set of ties 103. As explained in further detail below, the operator may select the desired operation for the current tamping conditions (i.e. number of ties per cycle, tie material, etc.) from a plurality of operations that have been loaded into the control device. When the operator begins the tamping operation, the propulsion device 104 begins moving the rail vehicle 100, while the movement device begins to control the seat 120.

[0043] According to some embodiments, at the beginning of the work cycle or when the operation parameters are changed, the machine will operate with the seat locked until the control device has collected sufficient profile information for the operations parameters that were selected. After sufficient profile information is collected, the seat will then start to move according to the profile information.

[0044] If the rail vehicle 100 must advance on the railroad track 101 until it reaches the first tie or set of ties 103 to be tamped, this is considered the beginning of a tamping cycle. As the rail vehicle 100 begins to advance toward the first tie or set of ties 103, the movement device 134 will move the seat 120 backwards relative to the frame assembly 102 as the rail vehicle 100 advances. The movement device 134 will move the seat 120 backwards at a speed that is less than the speed at which the rail vehicle 100 advances along the railroad. This backwards movement of the seat 120 is not at a generally constant speed because the forward movement of the rail vehicle 100 is not at a generally constant speed. As the rail vehicle 100 begins to advance, it will accelerate from a stationary position up to some top speed. When this occurs, the movement device 134 moves the seat 120 backwards at a rapid speed. As the rail vehicle 100 reaches the first tie or set of ties 103, the rail vehicle 100 will begin to slow down. The movement device 134 accordingly reduces the speed of the seat 120, but maintains the seat 120 moving backward. As such, while the rail vehicle 100 is advancing from a stationary starting position (i.e. at the beginning of the tamping cycle) to the first tie or set of ties 103, the seat 120 will be moving backwards relative to the frame assembly 102 at a lower speed than the speed at which the rail vehicle 100 advances along the railroad track 101. This results in the seat 120 moving forward at a generally constant speed relative to a fixed point outside of the rail vehicle 100 as the rail vehicle 100 advances to the first tie or set of ties 103. As the rail vehicle 100 reaches the first tie or set of ties 103, the seat 120 is in the rearward position.

[0045] Once the rail vehicle 100 reaches the first tie or set of ties 103, the rail vehicle 100 comes to a stop. As the rail vehicle 100 stops, the movement device 134 begins to move the seat 120 forward relative to the frame assembly 102 at a generally constant speed. The seat 120 will continue moving forward at this speed while the rail vehicle 100 is tamping the current tie or set of ties 103. In other words, while the tamping tools are being extended, tamping the current tie or set of ties 103, and being retracted, the seat 120 will be moving longitudinally forward at a generally constant speed. During this time, the rail vehicle 100 is stationary relative to a fixed point outside of the rail vehicle 100, while the seat 120 is moving forward at a generally constant speed relative to both the frame assembly 102 and the fixed point. The speed at which the movement device 134 moves the seat 120 forward is generally equal to the difference between the speed at which the rail vehicle 100 advances to the next tie or set of ties 103 and the speed at which the movement device 134 moves the seat 120 backward relative to the frame assembly 102. As such, the movement device 134 is able to maintain the seat 120 moving forward relative to a fixed point outside the rail vehicle 100 at a generally constant speed, regardless of the speed of the rail vehicle 100 as it advances along the railroad track 101.

[0046] Once the tamping device 106 has completed tamping the first tie or set of ties 103 and the tamping tools have withdrawn to their retracted position, the first tamping cycle has been completed. At this point, the seat 120 is in the forward position. As the next tamping cycle begins, the rail vehicle 100 begins to advance forward along the railroad track 101 to the next tie or set of ties 103. When this occurs, the movement device 134 again begins to move the seat 120 backwards relative to the frame assembly 102 at a slower speed than the speed at which the rail vehicle 100 advances forwards, as described above. The seat 120 moves backwards towards the medial position. Again, the movement device 134 continues to move the seat 120 backwards relative to the frame assembly 102 until the rail vehicle 100 stops over the next tie or set of ties 103, at which point in the cycle the seat 120 will be in the rearward position.

[0047] If the rail vehicle 100 begins the tamping operation when it is positioned over the first tie or set of ties 103 to be tamped, the movement device 134 will begin moving the seat 120 forward at a generally constant speed relative to the frame assembly 102 once the operator begins the tamping operation. Movement of the rail vehicle 100 and movement of the seat 120 relative to the frame assembly 102 then continues as described above.

[0048] Thus, despite the fact that the rail vehicle 100 is constantly stopping over a tie or set of ties 103 and then advancing forward, the seat 120 continually moves forward relative to a fixed point outside of the rail vehicle 100 at a generally constant speed. The movement device 134 is able to maintain the seat 120's forward movement by utilizing the profile corresponding to the current tamping operation and/or conditions. The profile contains data regarding the movement of the rail vehicle 100 during the tamping process, and thus the movement device 134 is able to time the motion of the seat 120 to coincide with the motion of the rail vehicle 100. The movement device 134 is thus able to move the seat 120 forward and backward relative to the frame assembly 102 so as to maintain an operator sitting in the seat 120 moving forward at a generally constant speed relative to a fixed point outside of the rail vehicle 100.

[0049] The control device is configured to move the seat 120 longitudinally forward and backward relative to the frame assembly 102 such that, during the tamping process, the seat 120 moves in a forward direction relative to a fixed point outside of the rail vehicle 100 at a generally constant speed. In some embodiments, the signals sent by the control device are based on the average of known profiles for the current tamping operation. A profile describes the movement of the rail vehicle 100 during a cycle of tamping operation. The distance the rail vehicle 100 travels between ties 103, the acceleration that the rail vehicle 100 undergoes, and the amount of time that the rail vehicle 100 is stationary during the tamping is contained within the profile.

[0050] In some embodiments, the moveable seat operation is based on a profile related to the type of tamping operation selected. For example, the tamping operation may be selected from a set of possible operations, which may include single tie single space tamping, single tie space double tamping, double tie space single tamping, double tie space double tamping, triple tie space single tamping, triple tie space double tamping, or other tamping operations. To start the process, the operator selects a tamping operation from the set of possible operations, and starts the machine to begin the tamping process. For the first several tamping cycles, the moveable seat remains stationary, as the machine records profile information to use for the moveable seat. When sufficient profile information is collected, the moveable seat will then begin cycling from its home position - moving backwards as the machine moves forward at a speed controlled by the profile. When the machine comes to a stop, so will the moveable seat, and then the seat will move forward - returning to the home position - while the tamping is taking place. The cycle then continues as the machine indexes forward, until the process is complete or until the operator changes the tamping operation.

[0051] In this manner, the method of moving the seat forward and backward relative to the frame assembly involves using average characteristics of the movement of the rail vehicle during the selected tamping operation. Thus, instead of accelerometers or other navigation systems, the control device utilizes the average profile for the current conditions of the tamping operation to communicate to the movement device precisely when the seat is to be moved forward or backward and at what speed, and may reduce or eliminate the delay in movement that resulted from prior art systems, as well as increase the accuracy of the movement of the operator relative to a fixed point outside of the rail vehicle.

[0052] The present disclosure also presents other advantages over previous machines. Because the cabin itself is stationary with respect to the remainder of the rail vehicle, any cables that run from the cabin to another part of the rail vehicle do not experience any extra movement or force. High flex cable is only needed for cabling that terminates on the moveable seat itself, and, in comparison with the prior art providing for a moveable platform supporting an operator cabin, the present disclosure allows for a larger percentage of the cabling in the machine to be standard cable instead of more expensive high flex cable, reducing the cost of the rail vehicle. Additionally, because the cabin is stationary with respect to the remainder of the rail vehicle, individuals are able to enter or leave the cabin during operation of the rail vehicle. As the door of the cabin remains fixed relative to the rest of the rail vehicle, an individual does not need to transition from a moving cabin to a stationary part of the rail vehicle (such as a ladder), making entering and exiting the cabin easier.

[0053] The present disclosure also reduces the number and severity of pinch points. As the cabin itself is not moving relative to the frame assembly, there are no pinch points created between the cabin and either the rail vehicle or support structures along the railroad. Further, any pinch points created inside of the cabin by the moving seat are less dangerous than with a moving platform. Because the seat is smaller and lighter than the entirety of the cabin, the force needed to move the seat within the cabin is much less than the force needed to move a platform with a cabin mounted upon it. Thus, the moving seat will have less momentum than a moving cabin, and any pinch points that may exist in the cabin between the moving seat and other parts of the cabin will be less dangerous to individuals who may have a body part within the path of the moveable seat assembly.

[0054] A further advantage of the present disclosure is that the moveable seat assembly is modular. Whereas previously proposed improvements in the art are large and costly to retrofit into then-existing machines, the moveable seat assembly of the present disclosure is easy to retrofit into existing rail vehicles. As opposed to replacing the entire cabin and platform assembly to install a moveable platform, existing rail vehicles need to only have the seat in the interior of the cabin modified. This results in a less expensive and time-consuming upgrade to take advantage of the present disclosure. [0055] According to other embodiments, known profiles for tamping operations of the same condition may be averaged and stored electronically in the control device. For example, different known profiles for single tie operation with concrete ties may be combined to create a single average profile for that condition. In general, concrete ties are typically spaced about twenty-four inches part. However, the distance between concrete ties on different railroad tracks may vary slightly. Averaging known profiles for railroads with concrete ties helps account for these variations in distance between successive ties. When the rail vehicle performs single-tie operation on a railroad track with concrete ties, the average profile for this condition may be selected by the operator. The rail vehicle, during operation, will move forward a certain distance to the next tie with a certain acceleration, and will be stationary for a certain amount of time while the tamping is taking place. As discussed above, the control device sends signals to the actuator to move the seat longitudinally backwards and forwards to compensate for the movement of the rail vehicle. Because the control device knows the average profile for this condition (i.e. single tie operation with concrete ties), the control device is able to accurately match the movement of the seat with the movement of the rail vehicle such that the operator sitting in the seat maintains a generally constant motion forward relative to a fixed point outside of the rail vehicle.

[0056] In some embodiments, average profiles for multiple different conditions may be stored in the control device and selected by the operator. A certain condition may include multiple variables that are accounted for by the averaging process, including, but not limited to: type of operation (e.g. single-tie, double-tie,); type of tie (e.g. concrete, wood); composition of ballast material, etc. The operator is able to choose a stored profile for the current condition that the rail vehicle will be operating on. Using the stored profile information, the control device is thus able to adjust the position of the seat simultaneously with the movement of the rail vehicle according to the profile.

[0057] As explained above, the rail vehicle is preferably equipped with a tracking device, such as an encoder wheel, that measures the generally linear movement of the rail vehicle over the rails. The tracking device is communicatively coupled to the control device. If an encoder wheel is used, the motion of the rail vehicle is measured in pulses per revolution. That is, the speed (rotation/time) for each revolution of the encoder wheel is tracked. The speed of the rail vehicle, or "movement data," is collected either constantly (analog) or, more typically, many times each second (digital). That data is converted to an electronic signal which is communicated to the control device. [0058] In some embodiments, the data that is communicated to the control device is used as feedback regarding the current conditions of the tamping operation. This feedback may be used to update the average profile for the current conditions to account for any deviations from the average profile. For example, wet or snowy conditions may cause a certain amount of slippage by the rail vehicle and/or result in a longer time traveling between ties or sets of ties. In these situations, if the control device does not receive feedback from the tracking device, the movement of the seat will, after the rail vehicle operates for some amount of time, become uncoordinated with the actual movement of the rail vehicle. The control device would thus not be able to optimally maintain the seat moving forward at a generally constant speed relative to a fixed point outside the rail vehicle. By receiving updated data on the current conditions from the tracking device, the control device is able to adjust the movement of the seat to account for deviations from the average profile of the current condition.

[0059] While the present invention has been described with reference to one or more particular embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present invention. Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the invention. It is also contemplated that additional embodiments according to aspects of the present invention may combine any number of features from any of the embodiments described herein.