Patent Publication Number: US-2018037239-A1

Title: Rail vehicle based deployable gage restraint measurement system

Description:
TECHNICAL FIELD 
     This disclosure relates to deployable gage restraint measurement systems and more specifically to light weight deployable gage restraint measurement systems. 
     BACKGROUND 
     Railroad tracks include two generally parallel rails that are attached to cross ties embedded in stone ballast using a variety of fasteners and methods. Each of the parallel rails comprises a number of individual rails that are attached together to form the entire length of the rail. Over time, the fasteners between the rails and/or the fasteners holding the rails to the cross ties can become loosened, damaged, missing, or the cross ties themselves can become rotten, cracked, or damaged, thereby requiring maintenance of the track. Identifying the specific locations on a railroad track that need maintenance is a round-the-clock job that requires large, heavy, machinery operated by experienced workers to replace or repair components. 
     One way to identify the locations needing maintenance is by using a gage restraint measurement system that has steel flanged wheels to apply loads to the rails and is pulled along the track by a full-size railroad car (i.e., a railbound train car that is only able to ride along a railroad track). The gage restraint measurement system applies an outward or lateral load to each of the rails through the flanged wheels while simultaneously applying a vertical load, the lateral load urging the rails away from each other, the vertical force keeping the gage restraint system wheel flanges from overriding the rail heads. If the fasteners holding one or both of the rails in a particular location were loosened, missing, and/or damaged, or the cross ties have lost integrity, the rails could move laterally, thereby increasing the gage of the rails. By gage of the rails it is meant the distance between the inside surface of the two parallel rails (e.g., measured 16 millimeters below the top surface of the rails). It is this movement of the rails (e.g., the change in the gage) resulting from the lateral load applied by the gage restraint measurement system that is measured and analyzed to determine where the track requires maintenance. 
     Prior gage restraint measurement systems were mounted under a full-size railbound railroad car (i.e., a train car that is only able to ride along a railroad track) by replacing one of the railroad car running axles with a specially designed axle capable of applying the gage restraint measurement system loads to the rails. Later gage restraint measurement systems were mounted under a full-size railbound railroad car in a deployable fashion such that a measurement axle assembly of the gage restraint measurement system was able to be lifted and lowered relative to the track such that when the gage restraint measurement system was not in use, the measurement axle assembly would be lifted off the rails and not be worn unnecessarily (e.g., reducing wear and tear, etc.). 
     However, some of these deployable gage restraint measurement systems were attached to the underside of a full-size railroad cars via a cross member and attached to the cross member were two laterally spaced very large and heavy trunnions. The trunnions were necessary such that the gage restraint measurement system could tilt relative to the underside of the railroad car to accommodate cross level in the track (e.g., height difference of the two generally parallel rails) and vehicle body movement on its suspension. Extending from each of the trunnions was a support frame. Attached to each of the support frames was a pair of linkages, which included an upper swing arm and a lower swing arm. The upper and lower swing arms were both attached at one of their ends to a respective one of the support frames and at the other of their ends to a respective end of the measurement axle assembly. 
     While these prior gage restraint measurement systems were able to deploy the measurement axle when needed, these prior gage restraint measurement systems required many very large and heavy components to do so (e.g., two trunnions, two pairs of upper and lower swing arms, etc.). As such, these prior gage restraint measurement systems needed to be mounted on very large vehicles, such as, for example, a full-size railbound railroad car. Further, in part due to the extreme weight of the these prior gage restraint measurement systems, the prior gage restraint measurement systems needed to be deployed (e.g. lowered into place prior to use) on a level track with no cross level because the cross level of the track would cause the gage restraint measurement system to swing to the lower side of the track during deployment, which could damage the gage restraint measurement system and/or cause the measurement axle to be misaligned with the track once deployed. 
     Thus, a need exists for relatively lighter deployable gage restraint measurement systems (e.g., by having relatively smaller and fewer mechanical parts) such that the gage restraint measurement systems can be deployed from lighter weight vehicles and vehicles with less available space (e.g., a hi-rail vehicle that can also be driven on standard roads to the rail test location or smaller railbound vehicles). There is also a need for gage restraint measurement systems that can be deployed on tracks with some cross level. The present disclosure is directed to solving these problems and addressing other needs. 
     BRIEF SUMMARY 
     According to some implementations of the present disclosure, a deployable gage restraint measurement system (“DGRMS”) includes a measurement axle assembly having a measurement-axle axis therethrough. The DGRMS further includes a cross member and a support frame pivotally coupled to the cross member. The DGRMS further includes a load cylinder pivotally coupled to the support frame and a swing arm pivotally coupled to (i) the load cylinder about a first axis of the swing arm, (ii) the support frame about a second axis of the swing arm, and (iii) the measurement axle assembly about a third axis of the swing arm. The DGRMS further includes an anti-rotational arm pivotally coupled to (i) the support frame and (ii) the measurement axle assembly. 
     According to some implementations of the present disclosure, a deployable gage restraint measurement system (“DGRMS”) includes a cross member, a first support frame pivotally coupled to the cross member, and a second support frame pivotally coupled to the cross member. The DGRMS further includes a measurement axle assembly that is coupled to the first and the second support frames. The DGRMS further includes a self-centering assembly extending from the cross member and being configured to engage the first and the second support frames to aid in maintaining rotational positions of the first and the second support frames during deployment of the measurement axle assembly on a track having cross level. 
     According to some implementations of the present disclosure, a deployable gage restraint measurement system (“DGRMS”) includes a measurement axle assembly, a cross member, a first support frame, a first vertical load cylinder, a first swing arm, and an anti-rotational arm. The measurement axle assembly includes a body, a first axle extending from the body in a first direction, a second axle extending from the body in an opposing second direction, a first wheel coupled to the first axle such that the first wheel is rotatable about a measurement-axle axis, and a second wheel coupled to the second axle such that the second wheel is rotatable about the measurement-axle axis. The first support frame is coupled to the cross member such that the first support frame is rotatable about a first vertical axis. The first vertical load cylinder has a first end and an opposing second end. The first end of the first load cylinder is pivotally coupled to the first support frame. The first swing arm has a first end and an opposing second end. The first end of the first swing arm includes a spherical bearing attached to the first axle. The opposing second end of the first swing arm is pivotally coupled to the opposing second end of the first vertical load cylinder. The first swing arm is pivotally coupled to the first support frame at a portion of the first swing arm between the first end and the opposing second end of the first swing arm. The anti-rotational arm is pivotally coupled to the first support frame and pivotally coupled to the measurement axle assembly such that rotation of the body of the measurement axle assembly about the measurement-axle axis is prevented. 
     According to some implementations of the present disclosure, a deployable gage restraint measurement system (“DGRMS”) includes a measurement axle assembly, a cross member, a first support frame, a second support frame, a first vertical load cylinder, a first swing arm, and a self-centering assembly. The measurement axle assembly includes a body, a first axle extending from the body in a first direction, a second axle extending from the body in an opposing second direction, a first wheel coupled to the first axle such that the first wheel is rotatable about a measurement-axle axis, and a second wheel coupled to the second axle such that the second wheel is rotatable about the measurement-axle axis. The first support frame is coupled to the cross member such that the first support frame is rotatable about a first vertical axis. The second support frame is coupled to the cross member such that the second support frame is rotatable about a second vertical axis spaced from the first vertical axis. The first vertical load cylinder has a first end and an opposing second end. The first end of the first load cylinder is pivotally coupled to the first support frame. The first swing arm has a first end and an opposing second end. The first end of the first swing arm includes a spherical bearing attached to the first axle. The opposing second end of the first swing arm is pivotally coupled to the opposing second end of the first vertical load cylinder. The first swing arm is pivotally coupled to the first support frame at a portion of the first swing arm between the first end and the opposing second end of the first swing arm. The self-centering assembly is coupled to the cross member. The self-centering assembly is configured to engage the first and the second support frames to aid in maintaining (i) a rotational position of the first support frame about the first vertical axis and (ii) a rotational position of the second support frame about the second vertical axis during deployment of the measurement axle assembly on a track having cross level. 
     According to some implementations of the present disclosure, a deployable gage restraint measurement system (“DGRMS”) for use in measuring a gage of a track having two generally parallel rails includes a cross member, a measurement axle assembly, a first support frame, a first vertical load cylinder, a first swing arm, an anti-rotational arm, a second support frame, a second vertical load cylinder, and a second swing arm. The cross member is configured to couple the deployable gage restraint measurement system to a vehicle. The measurement axle assembly includes a body, a first axle extending from the body in a first direction, a second axle extending from the body in an opposing second direction, a first wheel coupled to the first axle such that the first wheel is rotatable about a measurement-axle axis, and a second wheel coupled to the second axle such that the second wheel is rotatable about the measurement-axle axis. The first support frame is coupled to the cross member such that the first support frame is rotatable about a first vertical axis. The first vertical load cylinder has a first end and an opposing second end. The first end of the first load cylinder is pivotally coupled to the first support frame. The first swing arm has a first end and an opposing second end. The first end of the first swing arm includes a first spherical bearing attached to the first axle. The opposing second end of the first swing arm is pivotally coupled to the opposing second end of the first vertical load cylinder. The first swing arm is pivotally coupled to the first support frame at a portion of the first swing arm between the first end and the opposing second end of the first swing arm. The anti-rotational arm is pivotally coupled to the first support frame and pivotally coupled to the measurement axle assembly such that rotation of the body of the measurement axle assembly about the measurement-axle axis is prevented. The second support frame is coupled to the cross member such that the second support frame is rotatable about a second vertical axis. The second vertical load cylinder has a first end and an opposing second end. The first end of the second load cylinder is pivotally coupled to the second support frame. The second swing arm has a first end and an opposing second end. The first end of the second swing arm includes a second spherical bearing attached to the second axle. The opposing second end of the second swing arm is pivotally coupled to the opposing second end of the second vertical load cylinder. The second swing arm is pivotally coupled to the second support frame at a portion of the second swing arm between the first end and the opposing second end of the second swing arm. An extension of the first and the second vertical load cylinders causes the first and the second swing arms to pivot relative to the first and the second support frames in a first rotational direction, thereby deploying the measurement axle assembly onto the track. 
     The foregoing and additional aspects and implementations of the present disclosure will be apparent to those of ordinary skill in the art in view of the detailed description of various embodiments and/or implementations, which is made with reference to the drawings, a brief description of which is provided next. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other advantages of the present disclosure will become apparent upon reading the following detailed description and upon reference to the drawings. 
         FIG. 1  is a perspective view of a hi-rail vehicle with a deployable gage restraint measurement system coupled thereto according to some implementations of the present disclosure; 
         FIG. 2  is an assembled perspective view of the deployable gage restraint measurement system of  FIG. 1 ; 
         FIG. 3  is a partially exploded perspective view of the deployable gage restraint measurement system of  FIG. 1 ; 
         FIG. 4A  is a perspective view of a measurement axle assembly (with its wheels detached) of the deployable gage restraint measurement system of  FIG. 1 ; 
         FIG. 4B  is another perspective view of the measurement axle assembly (with its wheels detached) of the deployable gage restraint measurement system of  FIG. 1 ; 
         FIG. 5  is a perspective view of a cross member of the deployable gage restraint measurement system of  FIG. 1 ; 
         FIG. 6A  is a first perspective view of a first support frame of the deployable gage restraint measurement system of  FIG. 1 ; 
         FIG. 6B  is a second perspective view of the first support frame of the deployable gage restraint measurement system of  FIG. 1 ; 
         FIG. 7  is a perspective view of a first vertical load cylinder of the deployable gage restraint measurement system of  FIG. 1 ; 
         FIG. 8A  is a first assembled perspective view of a first swing arm of the deployable gage restraint measurement system of  FIG. 1 ; 
         FIG. 8B  is a second assembled perspective view of the first swing arm of the deployable gage restraint measurement system of  FIG. 1 ; 
         FIG. 8C  is an exploded perspective view of the first swing arm of the deployable gage restraint measurement system of  FIG. 1 ; 
         FIG. 9  is a perspective view of an anti-rotation arm of the deployable gage restraint measurement system of  FIG. 1 ; 
         FIG. 10A  is an assembled perspective view of a self-centering assembly of the deployable gage restraint measurement system of  FIG. 1 ; 
         FIG. 10B  is an exploded perspective view of the self-centering assembly of the deployable gage restraint measurement system of  FIG. 1 ; 
         FIG. 11A  is a top view of the deployable gage restraint measurement system of  FIG. 1  illustrating the self-centering assembly in a first or retracted position; 
         FIG. 11B  is a top view of the deployable gage restraint measurement system of  FIG. 1  illustrating the self-centering assembly in a second or engaged position; 
         FIG. 12A  is a side view of the deployable gage restraint measurement system of  FIG. 1  in a first or stored position; and 
         FIG. 12B  is a side view of the deployable gage restraint measurement system of  FIG. 1  in a second or deployed position. 
     
    
    
     While the present disclosure 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 present disclosure is not intended to be limited to the particular forms disclosed. Rather, the present disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims. 
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a vehicle  10  includes a cab  15  (e.g., for a driver of the vehicle  10 ), a frame  20  (e.g., a longitudinal continuous structure of the vehicle  10 ), a multitude of front and rear tires  30  (e.g., rubber tires) mounted to wheels for use in driving the vehicle  10  on standard roads, and rail wheel assemblies  40   a  and  40   b  including rail wheels  45  such that the vehicle  10  can ride along a railroad track on the rail wheels  45 . While the vehicle  10  is shown as being a hi-rail vehicle (e.g., a vehicle that can ride on standard roads with the tires  30  and ride on rails of a track with the rail wheel assemblies  40   a  and  40   b ), the vehicle  10  can be any type of vehicle, such as, for example, a full-size railroad car, a medium sized or relatively smaller railroad car, a relatively lighter weight railroad car as compared with a full-sized railroad car, a truck, a tractor, etc. 
     Mounted to an underside of the frame  20  of the vehicle  10  is a deployable gage restraint measurement system  100  of the present disclosure, which is referred to herein as DGRMS  100 . The DGRMS  100  is shown in a retracted or stored position as a measurement axle assembly  110  of the DGRMS  100  is positioned relatively higher or more vertical as compared with the wheels  45  of the rail wheel assemblies  40   a  and  40   b . As such, if the vehicle  10  were driven on a railroad track, only the wheels  45  of the rail wheel assemblies  40   a  and  40   b  would engage the rails of the track (e.g., until the DGRMS  100  is deployed/lowered). 
     The DGRMS  100  can deploy the measurement axle assembly  110  from its stored position ( FIGS. 1 and 12B ) to a deployed or operational position ( FIGS. 2 and 12A ) and can also cause the measurement axle assembly  110  to be retracted from the deployed or operational position ( FIGS. 2 and 12A ) back to the stored or retracted position ( FIGS. 1 and 12B ). When used on a vehicle, such as a hi-rail vehicle, the DGRMS  100  is mounted to the underside of the frame  20  of the vehicle  10 , and the DGRMS  100  is able to be transported between sites by road in a relatively easier fashion than some prior systems that needed to be mounted to full-size railroad cars. 
     Referring to  FIG. 2 , the DGRMS  100  is removed from the vehicle  10  to better illustrate the DGRMS  100 . Generally referring to the assembled view of the DGRMS  100  shown in  FIG. 2  and the partially exploded view of the DGRMS  100  shown in  FIG. 3 , the DGRMS  100  includes the measurement axle assembly  110 , a cross member  130 , first and second support frames  140   a ,  140   b , first and second vertical load cylinders  150   a ,  150   b , first and second swing arms  160   a ,  160   b , anti-rotation arm  190 , and self-centering assembly  200 , each of which is described in detail below in reference to additional figures. 
     The cross member  130  generally attaches the DGRMS  100  to the underside of the frame  20  of the vehicle  10  ( FIG. 1 ). Referring to  FIG. 2 , the measurement axle assembly  110  is generally coupled to the cross member  130  via a combination of the first and second support frames  140   a ,  140   b  and the first and second swing arms  160   a ,  160   b . The first vertical load cylinder  150   a  is coupled between the first support frame  140   a  and the first swing arm  160   a  and the second vertical load cylinder  150   b  is coupled between the second support frame  140   b  and the second swing arm  160   b  such that the first and second vertical load cylinders  150   a ,  150   b  can cause the measurement axle assembly  110  to be raised and/or lowered (e.g., deploy the measurement axle assembly  110  and/or store the measurement axle assembly  110 ). 
     Referring to  FIGS. 4A and 4B , the measurement axle assembly  110  includes a body  111 , first and second axles  120   a ,  120   b , and first and second wheels  125   a ,  125   b . The first wheel  125   a  couples to the first axle  120   a  such that the first wheel  125   a  is rotatable about the first axle  120   a  and a measurement-axle axis X m  of the measurement axle assembly  110 . Similarly, the second wheel  125   b  couples to the second axle  120   b  such that the second wheel  125   b  is rotatable about the second axle  120   b  and the measurement-axle axis X m  of the measurement axle assembly  110 . Alternatively, the first and second wheels  125   a ,  125   b  can be rotatable about different axes (e.g., different parallel axes). The first wheel  125   a  includes a flange  126   a  for engaging and loading a first rail of a pair of generally parallel rails during a measurement operation/session. Similarly, the second wheel  125   b  includes a flange  126   b  for engaging and loading a second rail of the pair of generally parallel rails during the measurement operation/session. 
     The body  111  of the measurement axle assembly  110  includes a first portion of a plurality of guide rails  112   a , a second portion of a plurality of guide rails  112   b , a first spindle block  114   a , and a second spindle block  114   b . The first spindle block  114   a  is fixed to the first portion of the plurality of guide rails  112   a  and slidable, along the measurement-axle axis X m , relative to the second portion of the plurality of guide rails  112   b  (e.g., via one or more bearings engaged with the second portion of the plurality of guide rails  112   b ). Similarly, the second spindle block  114   b  is fixed to the second portion of the plurality of guide rails  112   b  and slidable, along the measurement-axle axis X m , relative to the first portion of the plurality of guide rails  112   a  (e.g., via one or more bearings engaged with the second portion of the plurality of guide rails  112   b ). 
     The first axle  120   a  extends from the body  111  in a first direction (arrow A) along the measurement-axle axis X m  and the second axle  120   b  extends from the body  111  in an opposing second direction (arrow B) along the measurement-axle axis X m . Further, the first axle  120   a  is fixed to the first spindle block  114   a  such that linear movement of the first spindle block  114   a  along the measurement-axle axis X m , results in a corresponding linear movement of the first axle  120   a . Similarly, the second axle  120   b  is fixed to the second spindle block  114   b  such that linear movement of the second spindle block  114   b  along the measurement-axle axis X m  results in a corresponding linear movement of the second axle  120   b.    
     The measurement axle assembly  110  also includes a lateral load cylinder  127  (best shown in  FIGS. 11A and 11B ) that is positioned between the first and the second spindle blocks  114   a ,  114   b . The lateral load cylinder  127  is coupled to the first and the second spindle blocks  114   a ,  1114   b  such that the lateral load cylinder  127  can urge the first and the second spindle blocks  114   a ,  114   b  in opposite directions along the measurement-axle axis X m . Specifically, an extension or elongation of the lateral load cylinder  127  causes the lateral load cylinder  127  to urge the first spindle block  114   a  in the first direction (in the direction of arrow A), which causes the first axle  120   a  and the first wheel  125   a  coupled thereto to move laterally along the measurement-axle axis X m  in the first direction (in the direction of arrow A). Similarly, the extension or elongation of the lateral load cylinder  127  causes the lateral load cylinder  127  to urge the second spindle block  114   b  in the second direction (in the direction of arrow B), which causes the second axle  120   b  and the second wheel  125   b  coupled thereto to move laterally along the measurement-axle axis X m  in the second direction (in the direction of arrow B). As such, when the DGRMS  100  is deployed in the operational position ( FIG. 2 ) on a railroad track having two generally parallel rails, the extension or elongation of the lateral load cylinder  127  causes (i) the flange  126   a  of the first wheel  125   a  to laterally load a first of the rails in the first direction (in the direction of arrow A) and (ii) the flange  126   b  of the second wheel  125   b  to laterally load a second of the rails in the second direction (in the direction of arrow B). In some implementations, during extension and elongation of the lateral load cylinder  127 , the vertical load cylinders  150   a  and  150   b  can simultaneously load the first and the second swing arms  160   a ,  160   b  in such a fashion as to apply downward loads to the wheels  125   a  and  125   b , which aids in preventing the flanges  126   a  and  126   b  from overriding the heads of the rails. 
     The measurement axle assembly  110  also includes a first mounting block  116   a  coupled to the first spindle block  114   a  via a first bracket  118   a  and a second mounting block  116   b  coupled to the second spindle block  114   b  via a second bracket  118   b . The first and the second mounting blocks  116   a ,  116   b  can be used for mounting one or more items to the measurement axle assembly  110 . For example, as shown, in  FIGS. 4A and 4B , a first lube stick assembly  128   a  is mounted to the first mounting block  116   a  and a second lube stick assembly  128   b  is mounted to the second mounting block  116   b . The first lube stick assembly  128   a  is generally for applying lubrication to the first wheel  125   a  as needed during operation (best shown in  FIG. 2 ). The second lube stick assembly  128   b  is likewise generally for applying lubrication to the second wheel  125   b  as needed during operation (best shown in  FIG. 2 ). 
     In addition to providing a mount for the first and the second lube stick assemblies  128   a ,  128   b , the first mounting block  116   a  also provides a mount for pivotally connecting the anti-rotation arm  190  to the measurement axle assembly  110 . More specifically, an outer portion of the first mounting block  116   a  forms a clevis  117  such that a pin  117   a  can pivotally couple the anti-rotation arm  190  to the first mounting block  116   a  via the clevis  117 . It is contemplated that the anti-rotation arm  190  can be coupled to various other parts or elements of the measurement axle assembly  110  such that the anti-rotation arm  190  aids in and/or prevents rotation of the body  111  about the measurement-axle axis X m . While the DGRMS  100  only includes a single anti-rotation arm  190 , in some alternative implementations, the DGRMS  100  can have any number of anti-rotation arms (e.g., two, three, etc.). The first and the second brackets  118   a ,  118   b  can also provide mounting points for one or more bump-stops  119   a ,  119   b  to be attached for aiding in preventing the measurement axle assembly  110  from contacting the frame  20  of the vehicle  10  when, for example, the measurement axle assembly  110  is raised to the stored/retracted position ( FIGS. 1 and 12B ). 
     Referring to  FIG. 5 , the cross member  130  includes a central body  131 , first and second mounting assemblies  132   a ,  132   b , and first and second frame-support mounts  134   a ,  134   b . The central body  131  of the cross member  130  has a central axis Xc that is generally parallel with the underside of the body  20  of the hi-rail vehicle  10  and generally perpendicular to the rails of the track upon which the DGRMS  100  is deployed. The central body  131  is generally a hollow tube with a generally circular cross-section, although the central body  131  can have any shaped cross-section (e.g., square, oval, rectangle, triangle, polygonal, etc. or any combination thereof) and can be solid, hollow, or a combination thereof. The central body  131  provides a surface to which (i) the first and second mounting assemblies  132   a ,  132   b , (ii) the first and second frame-support mounts  134   a ,  134   b , and (iii) the self-centering assembly  200  are attached (shown in  FIG. 10 , not in  FIG. 5 ). 
     The first and the second frame-support mounts  134   a ,  134   b  are attached to the central body  131  and/or attached about opposing ends of the central body  131 . The first frame-support mount  134   a  includes apertures  135   a  that align with a first pair of apertures  131   a  in the central body  131 . Similarly, the second frame-support mount  134   b  includes apertures  135   b  that align with a second pair of apertures  131   b  in the central body  131 . As such, when the first support frame  140   a  is pivotally coupled to the cross member  130  via the first frame-support mount  134   a , for example, via one or more pins  138   a , the first support frame  140   a  is pivotal about a first vertical axis V 1  that is positioned through the center of the apertures  135   a  and the a first pair of apertures  131   a . Similarly, when the second support frame  140   b  is pivotally coupled to the cross member  130  via the second frame-support mount  134   b , for example, via one or more pins  138   b , the second support frame  140   b  is pivotal about a second vertical axis V 2  that is positioned through the center of the apertures  135   b  and the a second pair of apertures  131   b . The second vertical axis V 2  is spaced from and generally parallel to the first vertical axis V 1 . 
     The first and the second mounting assemblies  132   a ,  132   b  are also attached to the central body  131  and/or attached about opposing ends of the central body  131 . As shown, the first and the second frame-support mounts  134   a ,  134   b  are attached to the central body  131  between or inside of the first and the second mounting assemblies  132   a ,  132   b . Alternatively, the relative positioning of the first and the second mounting assemblies  132   a ,  132   b  and the first and the second frame-support mounts  134   a ,  134   b  can be reversed such that the first and the second mounting assemblies  132   a ,  132   b  are attached to the central body  131  between or inside of the first and the second frame-support mounts  134   a ,  134   b  (not shown). The first mounting assembly  132   a  includes a first mounting plate  133   a  and the second mounting assembly  132   b  includes a second mounting plate  133   b . The first and the second mounting plates  133   a ,  133   b  are for attaching the cross member  130  to the underside of the frame  20  of the vehicle  10  ( FIG. 1 ) by, for example, nuts and bolts, welding, rivets, glue, screws, nails, any other type of fastener, or any combination thereof. 
     Referring to  FIGS. 6A and 6B , the first support frame  140   a  includes a body  141  formed by a multitude of parts (e.g., plates, screws, welds, bolts, nuts, discs, etc.) having a generally outside surface  141   a  ( FIG. 6A ) and a generally inside surface  141   b  ( FIG. 6B ). 
     The first support frame  140   a  further includes first and second bearings  142   a ,  142   b  attached to the body  141 . The first support frame  140   a  is coupled to the cross member  130  by (i) positioning the first bearing  142   a  between an upper portion of the first frame-support mount  134   a  and an upper portion of the central body  131  such that a central axis X b1  of the first bearing  142   a  generally aligns with the first vertical axis V 1  ( FIG. 5 ) and (ii) positioning the second bearing  142   b  between a lower portion of the first frame-support mount  134   a  and a lower portion of the central body  131  such that a central axis X b2  of the second bearing  142   b  generally aligns with the first vertical axis V 1  ( FIG. 5 ). With the first and the second bearings  142   a ,  142   b  so positioned, the pins  138   a  can be positioned through the apertures  135   a  and the apertures  131   a  such that the first support frame  140   a  is pivotally coupled to the first frame-support mount  134   a  of the cross member  130  via the pins  138   a . The bearings  142   a  and  142   b  can be any type of suitable bearing, such as, for example, spherical bearings, cylindrical roller bearings, plain bearings, etc. 
     Once the first support frame  140   a  is pivotally coupled to the first frame-support mount  134   a  of the cross member  130  via the pins  138   a , the first support frame  140   a  can only rotate about the first vertical axis V 1 . That is, the first support frame  140   a  cannot tilt relative to, or with respect to, the first vertical axis V 1  and/or the cross member  130 . As such, the first support frame  140   a  differs from the heavier prior deployable gage restraint measurement systems where the prior support frame was attached to a trunnion such that the prior support frame could tilt and indeed needed the ability to tilt to operate properly. 
     The body  141  of the first support frame  140   a  includes and/or forms a pair of first apertures  144   a ,  144   b  that receive a first support-frame pin  145  therein. The apertures  144   a ,  144   b  define a first support-frame axis X sf1 . The first support-frame pin  145 , when coupled to the first support frame  140   a  via the pair of first apertures  144   a ,  144   b , pivotally couples the first vertical load cylinder  150   a  to the first support frame  140   a  such that the first vertical load cylinder  150   a  is able to rotate and pivot about the first support-frame pin  145  and the first support-frame axis X sf1  during, for example, operation of the first vertical load cylinder  150   a  (e.g., when the first vertical load cylinder  150   a  extends or contracts/retracts). 
     The body  141  of the first support frame  140   a  includes and/or forms a pair of second apertures  146   a ,  146   b  that receive a second support-frame pin  147  therein. The apertures  146   a ,  146   b  define a second support-frame axis X sf2 . The second support-frame pin  147 , when coupled to the first support frame  140   a  via the pair of second apertures  146   a ,  146   b , pivotally couples the first swing arm  160   a  to the first support frame  140   a  such that the first swing arm  160   a  is able to rotate and pivot about the second support-frame pin  147  and the second support-frame axis X sf2  during, for example, operation of the first vertical load cylinder  150   a  (e.g., when the first vertical load cylinder  150   a  extends or contracts/retracts). 
     The first support frame  140   a  also includes a clevis  148  that is attached to a generally horizontal plate portion of the body  141  of the first support frame  140   a . The clevis  148  can be attached to or integral with the generally horizontal plate portion of the body  141 . In some implementations, the clevis  148  is welded to the generally horizontal plate portion of the body  141 . The clevis  148  provides a mount for pivotally coupling the anti-rotation arm  190  to the first support frame  140   a  via a pin  148   a  as best shown in  FIG. 2 . 
     The first support frame  140   a  also includes a bearing plate  149  attached to the generally inside surface  141   b  ( FIG. 6B ) of the body  141  of the first support frame  140   a . The bearing plate  149  provides a surface that is directly engaged by a roller of the self-centering assembly  200  during deployment of the measurement axle  110  onto a track as described further below in reference to  FIG. 10 . Alternatively to the first support frame  140   a  including the bearing plate  149 , the first support frame  140   a  can lack the bearing plate  149  such that the self-centering assembly  200  just directly engages the generally inside surface  141   b  ( FIG. 6B ) of the body  141  of the first support frame  140   a.    
     The first support frame  140   a  is described herein as being coupled with pins  138   a ,  145 , and  147 . It is understood that any of these pins  138   a ,  145 ,  147  can be a standard mounting pin and/or a force sensing pin (e.g., a force sensing clevis pin). 
     While the second support frame  140   b  is not shown in  FIGS. 6A and 6B , the second support frame  140   b  is essentially the same as the first support frame  140   a  (e.g., a mirror image), except that the second support frame  140   b  mainly differs in that the second support frame  140   b  does not include a clevis (e.g., clevis  148 ) for mounting an anti-rotation arm thereto. As such, like reference numbers are used in the drawings for like parts of the second support frame  140   b  (e.g.,  FIGS. 2, 3 , etc.). Alternatively, the second support frame  140   b  can include a clevis (not shown) for mounting a second anti-rotation arm (not shown) thereto. 
     Referring to  FIG. 7 , the first vertical load cylinder  150   a  includes a body  151  and a piston  155 . The piston  155  is slidable relative to the body  151  along a vertical central axis V LC  of the first vertical load cylinder  150   a . The body  151  includes hydraulic fluid ports  152  that connect with tubes (not shown) for supplying and/or returning hydraulic fluid to a hydraulic fluid control system (not shown) for actuating the first vertical load cylinder  150   a . By actuating the first vertical load cylinder  150   a  it is meant that the hydraulic fluid control system can selectively cause the piston  155  to extend, cause the piston  155  to retract, cause the piston  155  to hold its position, cause the piston  155  to move as required to changes in rail height as responded to by the wheels  125   a  and  125   b  while maintaining a relatively constant load (e.g., depending on opposing loads imparted by the rails of the track etc.), etc. In some implementations, the relatively constant force maintained during movement of the piston  155  is provided by a hydraulic accumulator. The hydraulic fluid control system can include any number of pumps, reservoirs, tubes, couplings, accumulators, etc. 
     The first vertical load cylinder  150   a  further includes a first rod end  153   a  extending from a lower or rearward portion of the body  151 . The first rod end  153   a  forms an aperture therethrough having a central axis X LC1 . The first rod end  153   a  receives the first support-frame pin  145  therein such that the first vertical load cylinder  150   a  is able to rotate and pivot about (i) the first support-frame pin  145 , (ii) the first support-frame axis X sf1  ( FIGS. 6A and 6B ), and (iii) the central axis X LC1  during, for example, operation of the first vertical load cylinder  150   a  (e.g., when the first vertical load cylinder  150   a  extends or contracts/retracts). 
     The first vertical load cylinder  150   a  further includes a second rod end  153   b  extending from an upper or forward portion of the piston  155 . The second rod end  153   b  forms an aperture therethrough having a central axis X LC2 . The second rod end  153   b  receives a swing-arm pin  159  therein. The swing-arm pin  159 , when coupled to the first swing-arm  160   a , pivotally couples the first vertical load cylinder  150   a  via the second rod end  153   b  to the first swing arm  160   a  such that the first vertical load cylinder  150   a  is able to rotate and pivot about (i) the first swing-arm pin  159 , (ii) a first swing-arm axis X sa1  ( FIGS. 8A and 8B ), and (iii) the central axis X LC2  during, for example, operation of the first vertical load cylinder  150   a  (e.g., when the first vertical load cylinder  150   a  extends or contracts/retracts). 
     The first vertical load cylinder  150   a  is described herein as being coupled with pins  145  and  159 . It is understood that any of these pins  145  and  159  can be a standard mounting pin and/or a force sensing pin (e.g., a force sensing clevis pin). 
     While the second vertical load cylinder  150   b  is not shown in  FIG. 7 , the second vertical load cylinder  150   b  is the same as, or similar to, the first vertical load cylinder  150   b  (e.g., a mirror image)), except that the second vertical load cylinder  150   b  mainly differs in that the second vertical load cylinder  150   b  is coupled between the second support frame  140   b  (e.g., not the first support frame  140   a ) and the second swing arm  160   b  (e.g., not the first swing arm  160   a ). As such, like reference numbers are used in the drawings for like parts of the second vertical load cylinder  150   b  (e.g.,  FIGS. 2, 3 , etc.). 
     As described herein, the first and second vertical load cylinders  150   a ,  150   b  are hydraulically powered. Alternatively, the first and second vertical load cylinders  150   a ,  150   b  can be powered by electricity, compressed air, steam, or any other source of power. While the first and second vertical load cylinders  150   a ,  150   b  are described as being “vertical,” it is understood that the first and second vertical load cylinders  150   a ,  150   b  do not necessarily need to be vertical (e.g., the vertical central axes V LC  of the first and second vertical load cylinders  150   a ,  150   b  can be at any angle relative to vertical and/or horizontal). The first and second vertical load cylinders  150   a ,  150   b  can be actuated (e.g., extended or retracted) at the same time (synchronously) or at different times (asynchronously). 
     Referring to  FIGS. 8A, 8B, and 8C , the first swing arm  160   a  includes a body  161  formed by a multitude of parts (e.g., plates, spacers, apertures, plugs, bearings, pins, screws, welds, bolts, nuts, discs, etc.) having a generally outside surface  161   a  ( FIG. 8A ) and a generally inside surface  161   b  ( FIG. 8B ). As best shown in the exploded view of  FIG. 8C , the body  161  of the first swing arm  160   a  includes a first side plate  163   a , a second side plate  163   b , and a spacer  165 . The spacer  165  is positioned between and fixed to the first and the second side plates  163   a ,  163   b  as shown in  FIGS. 8A and 8B . As shown in  FIG. 8C , the spacer  165  has an elongated “C” shape that is similar to a pair of tongs or tweezers. Specifically, the spacer  165  has an upper plate  165   a , a lower plate  165   b , and an end plate  165   c  that connects the upper and the lower plates  165   a ,  165   b  together. Positioned between the upper and the lower plates  165   a ,  165   b  is a tube  168   a  that receives bearings  168   b  in each of its ends. A laterally oriented latch pin  165   d  is included and coupled between the first and the second plates  163   a ,  163   b  and is used to engage a safety hook (e.g., extending from the underside of the frame  20  of the vehicle  10 ) for stowage of the DGRMS  100  when not in use. As such, the laterally oriented latch pin  165   d  allows the first swing arm  160   a  to be hung from the safety hook (not shown) attached to the frame  20  of the vehicle  10  in the stored/retracted position ( FIGS. 1 and 12B ) to aid in preventing the measurement axle assembly  110  from deploying prematurely (e.g., accidentally deploying). The first plate  163   a  forms therein a first aperture  162   a , a second aperture  164   a , and a third aperture  166   a . Similarly, the second plate  163   b  forms therein a first aperture  162   b , a second aperture  164   b , and a third aperture  166   b.    
     With the first and the second plates  163   a ,  163   b  attached via the spacer  165 , the body  161  of the first swing arm  160   a  includes and/or forms a first pair of the apertures  162   a ,  162   b  that receive respective plugs  169  therein for receiving the swing-arm pin  159 . The apertures  162   a ,  162   b  and/or the plugs  169  define the first swing-arm axis X sa1 , which is the central axis through the apertures  162   a ,  162   b  and/or the plugs  169 . The swing-arm pin  159 , when coupled to the first swing arm  160   a  via the plugs  169 , pivotally couples the first vertical load cylinder  150   a  via the second coupler  153   b  to the first swing arm  160   a  such that the first vertical load cylinder  150   a  is able to rotate and pivot about the swing-arm pin  159  and the first swing-arm axis X sa1  during, for example, operation of the first vertical load cylinder  150   a  (e.g., when the first vertical load cylinder  150   a  extends or contracts/retracts). The plugs  169  can simply include openings therethrough for receiving the swing-arm pin  159  and/or the plugs  169  can include one or more other structures coupled thereto or in lieu thereof (e.g., instead of the plugs  169 ), such as, for example, bearings (e.g., spherical bearings, cylindrical bearings, etc.), discs, plates, etc. The swing-arm pin  159  can be a load sensing pin used to measure the load imparted from the first vertical load cylinder  150   a  into the first swing arm  160   a.    
     With the first and the second plates  163   a ,  163   b  attached via the spacer  165 , the body  161  of the first swing arm  160   a  includes and/or forms a second pair of the apertures  164   a ,  164   b  that receive respective ones of the bearings  168   b  therein for receiving the second support-frame pin  147 . The apertures  164   a ,  164   b  and/or the bearings  168   b  define the second swing-arm axis X sa2 , which is the central axis through the apertures  164   a ,  164   b  and/or the bearings  168   b  and/or the tube  168   a . The second support-frame pin  147 , when coupled to the first support frame  140   a  ( FIGS. 6A and 6B ) through (i) the apertures  164   a ,  164   b , (ii) the bearings  168   b  and (iii) the tube  168   a  of the first swing arm  160   a , pivotally couples the first swing arm  160   a  to the first support frame  140   a  such that the first swing arm  160   a  is able to rotate and pivot about the second support-frame pin  147  and the second swing-arm axis X sa2  during, for example, operation of the first vertical load cylinder  150   a  (e.g., when the first vertical load cylinder  150   a  extends or contracts/retracts). The bearings  168   b  and/or the tube  168   a  can simply provide an opening through the body  161  and/or the bearings  168   b  and/or the tube  168   a  can include one or more other structures coupled thereto or in lieu thereof (e.g., instead of the bearings  168   b , tube  168   a ), such as, for example, plugs (e.g., not a bearing), discs, plates, etc. 
     With the first and the second plates  163   a ,  163   b  attached via the spacer  165 , the body  161  of the first swing arm  160   a  includes and/or forms a third pair of the apertures  166   a ,  166   b  that at least partially receive therethrough a spherical bearing  167 . The spherical bearing  167  can be attached and/or fixed to the spacer  165 . The spherical bearing  167  is positioned to receive the first axle  120   a  therethrough when the first swing arm  160   a  is coupled to the measurement axle assembly  110  as shown in, for example,  FIG. 2 . The apertures  166   a ,  166   b  and/or the spherical bearing  167  define a third swing-arm axis X sa3 , which is the central axis through the apertures  166   a ,  166   b  and/or through the spherical bearing  167 . The first axle  120   a  ( FIGS. 4A and 4B ) extends through the spherical bearing  167  and pivotally couples the measurement axle assembly  110  to the first swing arm  160   a  such that the measurement axle assembly  110  is able to rotate and pivot with respect to the first swing arm  160   a  and about the third swing-arm axis X sa3  during, for example, operation of the first vertical load cylinder  150   a  (e.g., when the first vertical load cylinder  150   a  extends or contracts/retracts). The apertures  166   a ,  166   b  can simply be openings in the body  161  and/or include one or more other structures coupled thereto, such as, for example, discs, plates, spacers, etc. 
     While the second swing arm  160   b  is not shown in  FIGS. 8A, 8B, and 8C , the second swing arm  160   b  is the same as, or similar to, the first swing arm  160   a  (e.g., a mirror image), except that the second swing arm  160   b  mainly differs in that the second swing arm  160   b  generally couples the second support frame  140   b  (e.g., not the first support frame  140   a ) to the measurement axle assembly  110  via the second axle  120   b  (e.g., not via the first axle  120   a ). As such, like reference numbers are used in the drawings for like parts of the second swing arm  160   b  (e.g.,  FIGS. 2, 3 , etc.). 
     As described herein, the first and second swing arms  160   a ,  160   b  couple the first and the second support frames  140   a ,  140   b  to the measurement axle  110  via the first and the second axles  120   a ,  120   b , respectively. Specifically, the first swing arm  160   a  is a single mechanical linkage that couples the first support frame  140   a  to the measurement axle  110  via the first axle  120   a  and the second swing arm  160   b  is a single mechanical linkage that couples the second support frame  140   b  to the measurement axle  110  via the second axle  120   b . As such, the DGRMS  100  of the present disclosure does not use two separate and distinct linkages (e.g., an upper swing arm and a lower swing arm) to couple each of the support frames  140   a ,  140   b  to each end of the measurement axle assembly  110  like some prior systems. As such, the DGRMS  100  of the present disclosure uses less parts, is relatively lighter, and is less complicated mechanically to install and/or service. However, as such a coupling of the measurement axle assembly  110  could allow the measurement axle assembly  110  to rotate about the measurement-axle axis X m , the anti-rotation arm  190  is provided as described in reference to  FIG. 9  and elsewhere herein. 
     Referring to  FIG. 9 , the anti-rotation arm  190  includes an elongated body  191  having a first aperture  192  and a second aperture  193  therethrough. The first aperture  192  has a central axis X ara1  and the second aperture  193  has a central axis X ara2 . The first aperture  192  receives the pin  148   a  ( FIGS. 6A and 6B ) therein such that the anti-rotation arm  190  is able to rotate and pivot about the pin  148   a  and the central axis X ara1  during, for example, operation of the first vertical load cylinder  150   a  (e.g., when the first vertical load cylinder  150   a  extends or contracts/retracts). Similarly, the second aperture  193  receives the pin  117   a  ( FIGS. 4A and 4B ) therein such that the anti-rotation arm  190  is able to rotate and pivot about the pin  117   a  and the central axis X ara2  during, for example, operation of the first vertical load cylinder  150   a  (e.g., when the first vertical load cylinder  150   a  extends or contracts/retracts). While the anti-rotation arm  190  is shown as having a certain shape and cross-section, the anti-rotation arm  190  can have any shape and any cross-section or combination of shapes and cross-sections (e.g., a circular cross-section, a tubular cross-section, an oval cross-section, a square cross-section, a polygonal cross-section, etc.). 
     The anti-rotation arm  190  has a length L ara  measured between the central axis X ara1  of the first aperture  192  and the central axis X ara2  of the second aperture  193  that is the same as, or substantially the same as, a length L sa  ( FIGS. 8A and 8B ) of the first swing arm  160   a  between the second swing-arm axis X sa2  and the third swing-arm axis X sa3 . As such, during, for example, operation of the first and the second vertical load cylinders  150   a ,  150   b  (e.g., when the first and the second vertical load cylinders  150   a ,  150   b  extend or contract/retract), the anti-rotation arm  190  and the first swing arm  160   a  remain generally parallel to each other. 
     Referring to  FIGS. 10A and 10B , the self-centering assembly  200  includes a base  202 , a first self-centering sub-assembly  220 , and a second self-centering sub-assembly  240 . The base  202  is attached to the central body  131  of the cross member  130 . The base  202  includes four pairs of apertures  203   a ,  203   b ,  203   c , and  203   d  ( FIG. 10B ) that define four base axes V b1 , V b2 , V b3 , and V b4 . Each of the pairs of apertures  203   a ,  203   b ,  203   c , and  203   d  is coupled to a respective pin  204   a ,  204   b ,  204   c , and  204   d . In some implementations, each of the apertures  203   a ,  203   b ,  203   c , and  203   d  includes a plug or spacer mounted thereto for receiving the respective pins  204   a ,  204   b ,  204   c , and  204   d . As shown in  FIG. 10B , each of the first pair of apertures  203   a  includes a respective plug or spacer  205   a  therein. Similarly, each of the second pair of apertures  203   b  includes a respective plug or spacer  205   b  therein; each of the third pair of apertures  203   c  includes a respective plug or spacer  205   c  therein; and each of the fourth pair of apertures  203   d  includes a respective plug or spacer  205   d  therein. 
     The first self-centering sub-assembly  220  is coupled to the base  202 . The first self-centering sub-assembly  220  includes a first centering arm  225  and a first centering cylinder  235 . A first end  225   a  of the first centering arm  225  is pivotally coupled to the base  202  via a first one of the pins  204   a . A second opposing end  225   b  of the first centering arm  225  includes a first cam roller  230  attached to the second opposing end  225   b  via a pin  231 . The first cam roller  230  is positioned to engage the bearing plate  149  attached to the generally inside surface  141   b  ( FIG. 6B ) of the body  141  of the first support frame  140   a  when, for example, the first centering cylinder  235  is actuated. 
     A first end  235   a  of the first centering cylinder  235  is pivotally coupled to the base  202  via a second one of the pins  204   b . A second opposing end  235   b  of the first centering cylinder  235  is pivotally coupled to the first centering arm  225  via a pin  237 . Specifically, the first centering cylinder  235  is pivotally coupled to the first centering arm  225  at a portion of the first centering arm  225  between the first end  225   a  and the opposing second end  225   b  such that the first centering arm  225  is able to rotate and pivot about the first pin  204   a  and the first base axis V b1  during, for example, operation of the first centering cylinder  235  (e.g., when the first centering cylinder  235  extends or contracts/retracts). 
     Similarly to the first self-centering sub-assembly  220 , the second self-centering sub-assembly  240  is coupled to the base  202 . The second self-centering sub-assembly  240  includes a second centering arm  245  and a second centering cylinder  255 . A first end  245   a  of the second centering arm  245  is pivotally coupled to the base  202  via a fourth one of the pins  204   d . A second opposing end  245   b  of the second centering arm  245  includes a second cam roller  250  attached to the second opposing end  245   b  via a pin  251 . The second cam roller  250  is positioned to engage the bearing plate  149  ( FIGS. 2 and 11A ) attached to the generally inside surface of the body of the second support frame  140   b  when, for example, the second centering cylinder  255  is actuated. 
     A first end  255   a  of the second centering cylinder  255  is pivotally coupled to the base  202  via a third one of the pins  204   c . A second opposing end  255   b  of the second centering cylinder  255  is pivotally coupled to the second centering arm  245  via a pin  257 . Specifically, the second centering cylinder  255  is pivotally coupled to the second centering arm  245  at a portion of the second centering arm  245  between the first end  245   a  and the opposing second end  245   b  such that the second centering arm  245  is able to rotate and pivot about the fourth pin  204   d  and the fourth base axis V b4  during, for example, operation of the second centering cylinder  255  (e.g., when the second centering cylinder  255  extends or contracts/retracts). 
     As best shown in  FIG. 10B , when attaching the first and the second self-centering sub-assemblies  220 ,  240 , the first end  225   a  of the first centering arm  225  is positioned between the plugs  205   a  and pivotally coupled to the base  202  via the first one of the pins  204   a . The first end  235   a  of the first centering cylinder  235  is positioned between the plugs  205   b  and pivotally coupled to the base  202  via the second one of the pins  204   b . The first end  245   a  of the second centering arm  245  is positioned between the plugs  205   d  and pivotally coupled to the base  202  via the fourth one of the pins  204   d . The first end  255   a  of the second centering cylinder  255  is positioned between the plugs  205   c  and pivotally coupled to the base  202  via the third one of the pins  204   c . As shown in  FIG. 10B , the plugs  205   a ,  205   b ,  205   c , and  205   d  have certain heights/thicknesses corresponding to the thicknesses of the first ends of the components coupled thereto; however, it is contemplated that the plugs  205   a ,  205   b ,  205   c , and  205   d  can have any height/thickness. 
     As shown in  FIGS. 10A and 10B , the first centering cylinder  235  includes hydraulic fluid ports  239  and the second centering cylinder  255  includes hydraulic fluid ports  259  that connect with tubes (not shown) for supplying and/or returning hydraulic fluid to a hydraulic fluid control system (not shown) for actuating the first and the second centering cylinders  235 ,  255 . By actuating the first and the second centering cylinders  235 ,  255  it is meant that the hydraulic fluid control system can selectively cause a piston  238  of the first centering cylinder  235  and/or a piston  258  of the second centering cylinder  255  to extend, cause the pistons  238 ,  258  to retract, cause the pistons  238 ,  258  to hold its position, etc. The hydraulic fluid control system can be the same hydraulic fluid control system described above in connection with the operation of the vertical load cylinders  150   a ,  150   b , or the hydraulic fluid control system can be a different independent system that includes any number of pumps, reservoirs, tubes, couplings, accumulators, etc. 
     Referring to  FIG. 11A , a top view of the DGRMS  100  is shown with the self-centering assembly  200  in a first retracted (e.g., disengaged) position. As such, the pistons  238 ,  258  are generally retracted such that the first and the second cam rollers  230 ,  250  are not engaged with the respective bearing plates  149  on the respective inside surfaces of the first and the second support frames  140   a ,  140   b.    
     Referring to  FIG. 11B , a top view of the DGRMS  100  is shown with the self-centering assembly  200  in a second extended (e.g., engaged) position. As such, the pistons  238 ,  258  are generally extended such that the first and the second cam rollers  230 ,  250  engage the respective bearing plates  149  on the respective inside surfaces of the first and the second support frames  140   a ,  140   b . According to some implementations, with the self-centering assembly  200  in the second extended (e.g., engaged) position ( FIG. 11B ), the measurement axle assembly  110  can be deployed (e.g., by operation of the first and the second vertical load cylinders  150   a ,  150   b ) on a track having cross level, as the engagement of the roller bearings  230 ,  250  aids in preventing (or prevents) the first and the second support frames  140   a ,  140   b  from rotating about the first vertical axis V 1  ( FIG. 2 ) and the second vertical axis V 2  ( FIG. 2 ), respectively. 
     Referring to  FIG. 12A , the DGRMS  100  of the present disclosure is shown in the deployed/operational position such that the wheels  125   a ,  125   b  (only wheel  125   a  is shown) of the measurement axle assembly  110  contact and/or load a track T having generally parallel rails R 1  and R 2  (only a first rail R 1  is shown). The measurement axle assembly  110  can be retracted from the deployed or operational position ( FIGS. 2 and 12A ) to a stored/retracted position ( FIGS. 1 and 12B ). As shown in  FIG. 12B , once the measurement axle assembly  110  is retracted and/or stored, the wheels  125   a ,  125   b  no longer engage and/or load the rails R 1  and R 2  (only the first rail R 1  is shown) of the track T. 
     During operation of the DGRMS  100 , the first and the second swing arms  160   a ,  160   b  pivot and/or otherwise move with respect to various other components of the DGRMS  100  and about several different axes. Generally, operation of the DGRMS  100  causes the first swing arm  160   a  to (i) pivot about a first axis relative to the first vertical load cylinder  150   a , (ii) pivot about a second axis relative to the first support frame  140   a , and (iii) pivot about a third axis relative to the first axle  120   a . In some such implementations, the first axis is adjacent to a first end of the first swing arm  160   a , the third axis is adjacent to an opposing second end of the first swing arm  160   a , and the second axis is between the first axis and the third axis. Similarly, operation of the DGRMS  100  causes the second swing arm  160   b  to (i) pivot about a fourth axis relative to the second vertical load cylinder  150   b , (ii) pivot about a fifth axis relative to the second support frame  140   b , and (iii) pivot about a sixth axis relative to the second axle  120   b . In some such implementations, the fourth axis is adjacent to a first end of the second swing arm  160   b , the sixth axis is adjacent to an opposing second end of the second swing arm  160   b , and the fifth axis is between the fourth axis and the sixth axis. The first and the second swing arms  160   a ,  160   b  can move independently from one another such that during operation of the DGRMS  100 , the first axis and the fourth axis are not always or ever coincident; the second axis and the fifth axis are not always or ever coincident; and the third axis and the sixth axis are not always or ever coincident. In some alternative implementations, the first axis and the fourth axis are coincident; the second axis and the fifth axis are coincident; and the third axis and the sixth axis are coincident. 
     More specifically, in some implementations, when the DGRMS  100  moves from the stored position ( FIG. 12B ) to the deployed position ( FIG. 12A ), the first swing arm  160   a  pivots about the first swing-arm axis X sa1  ( FIGS. 8A-8C ), which is coincident with the central axis X LC2  of the second rod end  153   b  of the first vertical load cylinder  150   a  ( FIG. 7 ) as the swing-arm pin  159  is positioned through the first pair of the apertures  162   a ,  162   b  ( FIGS. 8A-8C ) and/or the plugs  169  ( FIG. 8C ) of the first swing arm  160   a  and through the aperture of the second rod end  153   b  of the first vertical load cylinder  150   a  ( FIG. 7 ). Further, the first swing arm  160   a  pivots about the second swing-arm axis X sa2  ( FIGS. 8A-8C ), which is coincident with the second support-frame axis X sf2  of the first support frame  140   a  ( FIGS. 6A and 6B ) as the second support-frame pin  147  is positioned through the pair of second apertures  146   a ,  146   b  ( FIGS. 6A and 6B ) of the first support frame  140   a  and through the apertures  164   a ,  164   b  ( FIGS. 8A-8C ) and/or the bearings  168   b  of the first swing arm  160   a . Even further, the first swing arm  160   a  pivots about the third swing-arm axis X sa3  ( FIGS. 8A-8C ), which is coincident with the measurement-axle axis X m  ( FIGS. 4A and 4B ) as the first axle  120   a  is positioned through the spherical bearing  167 . 
     A comparison of  FIGS. 12A and 12B  illustrates that the anti-rotation arm  190  remains parallel with the first swing arm  160   a  during, for example, operation of the first and the second vertical load cylinders  150   a ,  150   b  (e.g., when the first and the second vertical load cylinders  150   a ,  150   b  extend or contract/retract) between the extended/deployed position ( FIG. 12A ) and the retracted/stored position ( FIG. 12B ). 
     While the present disclosure has been described with reference to one or more particular embodiments and implementations, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present disclosure. Each of these embodiments and implementations and obvious variations thereof is contemplated as falling within the spirit and scope of the present disclosure, which is set forth in the claims that follow.