FIELD OF THE INVENTION The invention relates to locomotive manufacture, and more specifically to a method and apparatus for construction of a monocoque locomotive.

BACKGROUND OF THE INVENTION Locomotive bodies are generally constructed in one of two distinct styles — monocoque style and conventional style. Monocoque locomotive car bodies are generally more structurally sound and may be made lighter and more aerodynamic. However, monocoque locomotives are generally more difficult to manufacture and therefore may be more costly. Conventional style locomotive car bodies are generally simpler to manufacture and to equip.

Monocoque locomotive car body construction may be referred to by several names such as stressed skin, aircraft style, automobile style, or uni-body style construction. The fundamental characteristic of monocoque construction is that the outer car body segments are joined together, such as by welding, such that the body of a completed monocoque locomotive is effectively a unitary structure. Because the car body segments are fixedly joined, they may be load sharing members. This reduces or eliminates the need for a supporting frame, thus making the locomotive lighter. The monocoque locomotive takes longer to manufacture in part because installation of the internal components, such as a diesel engine or an alternator, is relatively cumbersome. The components must be installed through the relatively few openings in the locomotive body, and the majority of the work must be performed from inside the locomotive body. Installation of some components, such as piping and cabling, may require overhead lifting of the locomotive. Also, the manufacture of a monocoque

locomotive takes more time because the detailing, finishing, and strength requirements are more difficult to achieve, and the car body segments may distort during welding or loading. A conventional freight locomotive is generally built from the bottom up. The underframe may be first equipped with deck mounted components, such as piping and cabling, and possibly a diesel engine and other deck mounted internal components. The internal components may be mounted on individual platforms, thus adding to the physical size and weight of the locomotive. The individual platforms are then placed upon the underframe. Lastly, an outer sheet metal structure may be affixed over the platform sections. The outer shell, if one is used, may be discontinuous, and is not substantially load bearing.

These two types of locomotives have remained the state of the art for over twenty years. Further, it has become an industry paradigm that the manufacturing processes associated with these types of car bodies are inherent in their design. The methods of manufacturing these locomotives have not substantially changed in decades.

The method of manufacturing the locomotive includes both the manufacturing of the body itself and installation of the internal components. The conventional method of manufacturing a monocoque locomotive car body is time consuming and expensive. Also, it has become a generally accepted notion that, as stated in U.S. Patent No. 5,577,449 issued to Kleiner et al. on Nov. 26, 1996, in fabricating a monocoque locomotive, the "carbody is separately assembled and then the internal components are installed." Often, this is because the car body will be manufactured in a different place or even a different company at a different time. Generally, assembly of the finished locomotive and welding of the body segments are considered to be two separate skills.

As a result of the difficulty in manufacturing the body and equipping the locomotive, manufacturing of a monocoque locomotive is simply more difficult, time- consuming, and expensive than manufacturing of a conventional locomotive.

SUMMARY OF THE INVENTION

The invention provides an improved method of manufacturing a monocoque locomotive. The method not only enhances the production of the car body itself, but also makes equipping of the locomotive more efficient. In part, the invention recognizes that some of the advantages of conventional locomotive manufacturing may be applied to monocoque locomotive manufacturing. Though it was previously believed that the difficulties of monocoque locomotive construction were inherent in the design, the present invention fundamentally changes the manufacturing process to achieve many of the benefits of monocoque locomotives without the usually associated manufacturing disadvantages. The finished product, however, retains the advantages of a monocoque locomotive and may be made functionally equivalent to prior art monocoque locomotives. More particularly, the present invention provides a method of manufacturing a monocoque locomotive. The monocoque locomotive is comprised of an underframe and an upper body. The method comprises the steps of constructing an underframe for the monocoque locomotive and constructing an upper body structure separately from the underframe. The upper body structure comprises a majority of the monocoque locomotive upper body. Lastly, the upper body structure is joined with the underframe. As a benefit of the separate manufacturing of the underframe and the upper body structure, internal component subassemblies may be fixed to the underframe or to the upper body structure before the joining of

the underframe with the upper body structure. Such internal component subassemblies that may be fixed to the underframe may include, for example, an engine, a generator, an engine support rack, an air brake rack, or a dynamic brake. Such internal component subassemblies that may be fixed to the upper body structure may include, for example, a horn assembly, a radiator and fan rack, or a dynamic brake grid.

Additionally, the underframe and the upper body structure may each be set to a selected camber.

That camber may be set, such as with a fixture, during the construction and installation of internal components. Further, the camber may be set through the joining of the car body. The camber of the upper body structure may be set to cooperate with the camber of the lower body structure. Thus, the shapes of the body structures may be more precisely fixed and held during construction of the locomotive car body.

Additionally, the invention provides a fitting structure at a portion of the interface between the upper body structure and the other portion of the locomotive body. For example, if the upper body structure is the entire upper body, then the other portion of the locomotive body comprises the underframe. The interface would then be substantially along a horizontal plane between the upper body and the underframe. As another example, if the upper body structure is an intermediate section of the upper body between a cab section and a hood section, then the other portion of the locomotive body would comprise the underframe, the cab section, and the hood section. Then interface would then be substantially along the horizontal plane between the upper body and the underframe, as well as the horizontal planes between the intermediate section and the cab section, and between the intermediate section and the hood section.

Such a fitting structure may be positioned at a portion of the interface of the upper body structure

such that the upper body structure and the other portion of the locomotive body can be fixed to the fitting structure. The fitting structure reduces the precision necessary at the interface. The top or bottom of the fitting structure may be made a selected curvature to mate to the corresponding portion of the underframe or the upper body structure.

The invention also provides a method of manufacturing a monocoque locomotive comprising the steps of constructing an underframe for the monocoque locomotive, providing segments of a locomotive upper body structure, providing a fixture to hold the underframe and the upper body segments in structural alignment, installing at least one internal component subassembly to either the underframe or the segments of the upper body structure of the monocoque locomotive, and then joining at least one segment of the upper body structure to the underframe after the installing step. In this way, the shape of the locomotive body may be held while construction of both internal components and upper body segments takes place.

In yet another aspect, the invention provides a method of manufacturing an upper body structure for a monocoque car body. The method comprises the steps of providing segments of an upper body structure, providing a fixture to hold the segments in structural alignment, fixing the segments in the fixture, and fastening the upper body segments together while in the fixture to form a unitary structure that may subsequently be mated to an underframe. The upper body structure comprises at least sidewalls of a monocoque car body, and may include sidewalls and roof sections. Using such a method, the upper body structure may be set to a selected camber. Such a fixture may include a fixture base or internal braces in the upper body structure.

The invention further provides a method of manufacturing an upper body structure for a monocoque upper body. The upper body includes a cab section, a hood section, and an intermediate section between the cab section and the hood section. The method comprises the steps of providing segments of an upper body structure for the monocoque upper body, wherein the upper body structure comprises the intermediate section of the upper body, providing a fixture to hold the segments in structural alignment, fixing the segments in the fixture, and fastening the upper body segments together while in the fixture to form a unitary structure that may subsequently be mated to an underframe. Such a monocoque upper body may be used in monocoque locomotives and other similar monocoque body structures, such as buses. The upper body structure may be set to a selected camber, and the fixture may include, for example, a fixture base or an internal brace. The invention further provides a method of manufacturing an underframe for a locomotive car body. The method comprises the steps of providing segments of a locomotive underframe structure, providing a fixture to hold the segments in structural alignment, fixing the segments in the fixture, and fastening the underframe segments together while in the fixture to form a unitary structure that may subsequently be mated to an upper body structure. Again, the underframe structure may be set to a selected camber. Such a fixture may include a plate and stops, and the underframe segments can then be secured against the stops.

Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic chart of the sequential stages of construction of a monocoque locomotive according to the prior art. Fig. 2 is a schematic chart of the sequential stages of construction of a monocoque locomotive according to the invention.

Fig. 3 is a schematic illustration of the upper body segments of the locomotive. Fig. 4 is a schematic illustration of the upper body segments of Fig. 3 joined to a fixture.

Fig. 5 is a view taken along line 5-5 in Fig. 4.

Fig. 6 is a schematic illustration of the upper body structure mounted to the fixture base, with several internal component subassemblies affixed.

Fig. 7 is a schematic illustration of the underframe structure on top of a assembly fixture.

Fig. 8 is a schematic illustration of the underframe structure on the fixture assembly, with some internal component subassemblies affixed.

Fig. 9 is a schematic illustration of a rib fixture assembly mounted to the upper body structure.

Fig. 10 is a view taken along line 10-10 in Fig. 9.

Fig. 11 is a schematic illustration of the upper body structure mounted within the rib fixture and being lowered onto the underframe.

Fig. 12 is a schematic illustration of the upper body structure within the rib fixture and being mounted to the underframe.

Fig. 13 is a schematic illustration of the completed locomotive body.

Fig. 14 is a perspective view of the locomotive body.

Fig. 15 is a perspective view of an upper body structure separate from an underframe with a cab and hood end installed.

Fig. 16A is a perspective view of an underframe of the monocoque locomotive with the cab and hood assembly mounted, and with a fitting structure on the top surface of the underframe. Fig. 16B is an enlarged partial side view a portion of the fitting structure shown in Fig. 16A.

Fig. 16C is a cross section of the fitting structure, taken along line 16C-16C of Fig. 16B.

Fig. 17 is a perspective view of the fixture for setting the cumber of the underframe.

Fig. 18 is a perspective view of the upper body structure of the monocoque locomotive held in a fixture base and also having a lifting fixture attached. Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of the construction and the arrangements of processes set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

DETAILED DESCRIPTION

Overall Process

In the present invention, a monocoque locomotive body generally refers to the car body itself, without internal component subassemblies or finishing operations. Such a locomotive body is shown as 49 in Fig. 14. The locomotive upper body generally refers to that part of the car body above the underframe, typically comprising a cab section at the front end, a hood section at the rear end, and an intermediate section between the cab section and the hood section. An upper body structure is composed of

segments and is a portion of the upper body. Likewise, an underframe structure is composed of segments and is a portion of the underframe. The upper body structure may comprise, for example, the intermediate section 55 (Figs. 3 and 15) or the entire upper body 50 (Fig. 3).

Figs. 1 and 2 depict schematically the conventional approach and an improved approach to building a monocoque locomotive that is taught by the invention. The figures depict the various stages of locomotive manufacture over time from left to right.

As shown in Fig. 1, in the conventional approach, at step S20 the underframe subassemblies or segments are constructed. As used in Figs. 1 and 2, "Subs" refers to subassemblies that are segments of the completed structure. At step S22, the underframe is then constructed from the various underframe subassemblies or segments. At step S24, the car body subassemblies or segments may be assembled simultaneously with the underframe construction in a separate location. Then at step S26, the car body is assembled from the individual subassemblies or segments. Usually, the underframe is first built, and then the other car body subassemblies or segments are built onto the underframe. After the locomotive car body construction is complete, at step S28, the locomotive is equipped with the internal component subassemblies. Step S28 takes a large amount of time and energy due to space and access restrictions. Finally, at step S30 the locomotive is painted, tested and shipped to complete the assembly process.

As shown in Fig. 2, some similar steps may take place in the improved process of the invention. However, due to the improved approach of the invention, the steps may take place simultaneously. Also, the steps themselves may be more efficient. This saves overall construction and cycle time of building each individual locomotive. The net result is that due to the improved approach to locomotive construction, the

locomotive according to the present invention may be assembled in as little as approximately two weeks. The prior art conventional approach may take as much as three months from start to completed locomotive. Additionally, the method of locomotive construction of to the invention may reduce the total number of work hours of locomotive construction as much as 30%. This is in part because the improved process allows better access to the locomotive and thereby makes the individual construction processes more efficient.

At step S32, the underframe subassemblies or segments are constructed similar to the conventional approach. At step S36, the underframe may then be constructed. The construction of the underframe may be performed in an improved manner, as described hereinafter. At step S34, the car upper body structure subassemblies or segments may be separately constructed. At step S40 the underframe then may be equipped with individual component subassemblies. Simultaneously, at step S38 the car upper body structure may be constructed, and at step S42 the car upper body structure may be equipped with individual component subassemblies. Finally, at step S44 the assembly of the car upper body schedule to the underframe completes the assembly of the locomotive body. However, in the method of the invention, the car body may be partially or fully equipped when it is assembled. The equipping of the locomotive is then finished at step S46 and the locomotive is then painted, tested and shipped at step S48, similar to the conventional approach.

Figs. 3 through 13 illustrate schematically the process of assembling a monocoque locomotive according to the present invention. In Fig. 3, the locomotive upper body 50 is shown as comprising a number of discrete segments. The upper body 50 comprises the locomotive car body above the underframe. The cab section is depicted as cab end structure 52 at

-li¬ the very front of the locomotive. The hood section is depicted as hood end structure 54 at the rear of the locomotive. The intermediate section 55 of the upper body structure comprises three segments, the forward segment 56, a mid segment 58, and a rear segment 60 of the intermediate section of the upper body structure.

Thus, the "Car Body" of Fig. 1, shown as locomotive body 49 in Fig. 14, is typically completely assembled before equipping the locomotive. In the improved process of Fig. 2, the "Underframe," shown as underframe 72 in Figs. 7 and 14, may be assembled and equipped before assembly to an upper body structure. The "Car Upper Body Structure," shown as upper body structure 51 in Figs. 7 and 15, may be assembled and equipped before assembly to the underframe.

An upper body structure may comprise in some cases the entire upper body 50, as shown in Figs. 3 through 6. Alternatively, an upper body structure may in some cases comprise, for example, the intermediate section 55 only (forward segment 56, mid segment 58, and rear segment 60), as shown in Fig. 15. The forward segment 56, mid segment 58, and rear segment 60 each comprise a pair of sidewalls on each side of the locomotive body and a roof section, as shown in further detail hereinafter.

As shown in the schematic of Fig. 3, the overall length of the locomotive is divided into 5 segments. An ordinary locomotive is about 75 feet in length. The intermediate section 55 typically comprises about 50 to 60 feet of the length.

Previously, segments over about 20 feet in length have been exceedingly difficult to work with. As a result, it is customary to divide the length as shown. Other configurations are, of course, also possible. As shown in Figs. 4 and 5, the locomotive upper body structure segments are assembled together separately from the underframe 72 (Fig. 7) by means of a fixture base 62. Fixture base 62 is fixed to the

underside of the upper body structure segments during assembly of the upper body structure 51. A number of clamps 64 are used to hold the upper body structure segments (cab end structure 52, forward segment 56, mid segment 58, rear segment 60, and hood end structure 54) in structural alignment. Clamps 64 may comprise, for example, turnbuckles.

As a result of the welding and other forces imparted on the upper body structure segments during assembly, the upper body structure segments tend to deform during assembly. The fixture, as described hereinafter in further detail, maintains the shape of the upper body structure such that it may be subsequently mated to the underframe. The underside of the upper body structure must therefore be held relatively rigidly to a predetermined shape. The other portions of the upper body structure segments must be held such that they are in alignment with each other. Fig. 6 shows the equipping of some of the individual component subassemblies to the upper body structure of the locomotive. A horn assembly 66, a radiator and fan rack 68, and dynamic brake grids 70 have been mounted to the upper body structure 51 while the upper body structure 51 is set in the fixture base 62. Such subassemblies are well known in the art.

Fig. 7 shows the assembly of an underframe 72 within the underframe fixture 74. The underframe 72 comprises fuel tank 76, first cross member 78, second cross member 80, first end assembly 82 and second end assembly 84. The various segme -s of the underframe are assembled while the structi L alignment of the segments is held by the fixture Again, as a result of the forces of welding which occur during assembly, the structure tends to distort during assembly. The fixture holds the underframe to the dimensions required for assembly of the locomotive. Again, such subassemblies are well known in the art.

As shown in Fig. 8, the various internal component subassemblies may be mounted to the underframe 72 while the underframe remains held in fixture 74. The internal component subassemblies include an engine 86, a generator 88, an engine support rack 90, an air brake rack 92, and an end controls box 94.

Next, as shown in Figs. 9 through 12, the equipped upper body structure is mounted to the equipped underframe. Figs. 9 and 10 show the upper body structure 51 within a rib fixture 96 that is clamped around the outside of the upper body structure 51 to hold the side walls of the upper body structure 51 in structural alignment. As shown in Fig. 11 the rib fixture 96 also facilitates the lifting of the upper body structure 51 over the underframe 72. Next, as shown in Fig. 12, the upper body structure 51 mounted within the rib fixture 96 is lowered onto the underframe 72. Finally, as shown in Fig. 13, the entire locomotive 98, including the upper body structure and the underframe, are joined together to comprise a nearly completed locomotive.

Figs. 14 and 15 show in greater detail a locomotive body that may be manufactured in accordance with the invention. Fig. 14 shows the completed locomotive body 49. As shown in Fig. 14, each of the segments of the intermediate section 55, including forward segment 56, mid segment 58, and rear segment 60, are comprised of a left sidewall 100, a right sidewall 102, and a roof section 104.

If the locomotive body is completed prior to equipping of the locomotive with internal component subassemblies as in the prior art, the only access to the inside of the locomotive body is through openings 105 in the roof sections 104 of the locomotive body 49. The three large openings 105 depicted in Fig. 14 thus comprise the majority of the access to the internal space of the locomotive. Therefore, manufacturing a

- 14 - locomotive according to the prior art method is difficult and cumbersome.

Fig. 15 shows a locomotive upper body structure 51 assembled separately according to the present invention, consisting of three wall sections and roof sections joined together, but not including the hood and cab assembly. As shown in Fig. 15 the hood and cab segments have previously been joined to the underframe. In a typical locomotive, the underframe may be constructed of a relatively inexpensive plain carbon steel and the locomotive body above the underframe may be constructed of stainless steel. Stainless steel has excellent wear resistance properties, and gives the locomotive a very pleasing aesthetic appearance. However, while stainless steel makes an excellent finished product, it is very difficult to use in manufacturing a locomotive. During welding, the stainless steel tends to distort significantly more than plain carbon steels. Thus, in locomotives using a stainless steel construction, the improved assembly processes of the present invention are more useful and important.

Because welding of the car body causes distortion of the car body segments and makes structural alignment more difficult, it may be advantageous to use a welding process that does not put as much heat into the metal. For example, instead of the more common direct current arc welding processes, an alternating current pulse arc welding process will cause less distortion of the metal.

In welding the locomotive body together, the first step is typically to fit and tack the selected body segments in place. Then the body or structure may be welded into a unitary structure, usually by welding vertical seams first, then progressing from the center out and from the bottom up. Such welding processes may be performed according to known welding principles.

Fittinσ Structure

Fig. 16A shows underframe 72 with a fitting structure 110 mounted to the top surface. The fitting structure 110 appears as a ladder-like frame (shown in Fig. 16B) from the inside of the locomotive, and is shown as being fixed to the outside of the top horizontal surface of the underframe 72. The fitting structure 110 is used to adapt the mating surfaces of the underframe 72 and an upper body structure. As shown in Fig. 16A, the underframe 72 has the cab end structure 52 and the hood end structure 54 mounted to the underframe 72. Therefore, the upper body structure that is manufactured separately will comprise the intermediate section 55 of the upper body. As a result, the upper body structure defines an interface with the underframe that includes not only the horizontal plane between the upper body structure and the underframe, but also the vertical planes between the upper body structure and the cab end structure 52 and the hood end structure 54. A fitting structure may be used at the entire interface, or merely at a portion, such as the horizontal portion as shown in Fig. 16A.

Essentially, the fitting structure 110 may be positioned at the interface between the upper body structure and the rest of the body of the locomotive in order to facilitate joining of the upper body structure with the rest of the locomotive body. The sidewalls 100 and 102 (Fig. 14) of the locomotive may be shortened by the height of the fitting structure 110 in order to maintain the same height of the locomotive. As shown in Figs. 16B and 16C, the fitting structure 110 comprises an outer shell 112 and inner ribs 114. The outer shell 112 includes a top surface 116 and an outer surface 118. The top surface 116 may be held flat to mate to a flat bottom surface of an upper body structure. The inner ribs define a bottom surface 108

that may be trimmed to fit the top surface of the underframe 72.

Importantly, the outer shell 112 and the inner ribs 114 are joined by a lap joint 130 formed of overlapping sheets. Such a joint may accommodate dimensional variation in manufacturing because the inner ribs 114 may be moved relative to the outer shell 102 before the fitting structure is finally welded in place. Such a lap joint may be used at other portions of the interface, such as the vertical planes where the cab end structure 52 and the hood end structure 54 mate to the upper body structure, in order to accommodate dimensional variation.

At the interfaces, the structure will be relatively rigid in directions in the plane of the locomotive body, and may therefore require such dimensional accommodation to allow the pieces to fit together during final assembly. As will be appreciated in the art, the body panels will be relatively flexible in a transverse direction, so the panels may generally be made to fit over each other by bending them.

The fitting structure may also facilitate manufacture of the locomotive because it raises the weld line with the upper body structure. Piping and cabling and other equipping of the underframe may thus be performed before the upper body structure is adhered to the underframe, because the welding takes place at a distance from such piping and cabling.

Underframe Fixture

The underframe may be rigidly fixtured during assembly of the underframe segments. In this way, the shape of the underframe may be set during assembly such that the underframe may subsequently be mated to the upper body structure. Further, this aids in precisely maintaining the shape of the underframe during welding and other assembly operations. Internal component subassemblies and car body segments may then be mounted

to the underframe while the shape of the underframe is held to a selected shape.

The shape of the underframe may be set to a selected curvature. Such a curvature may be irregular, but is commonly a cambered shape along the longitudinal axis of the locomotive, as known in the art. Therefore, viewed from the side, a cambered locomotive will bow upwards at the center. Typically, such a camber would be barely noticeable in a finished locomotive. The locomotive is typically about 75 feet in length and the height of the center (camber at the center) of the locomotive relative to the front and rear ends is usually less than one inch, and may be on the order of several millimeters. As used herein, a flat surface is considered to be a selected camber of zero.

In prior art locomotive manufacturing, the underframe is assembled with a relatively large amount of camber because the underframe will distort during assembly and during fixing of the internal component subassemblies. The camber is set higher so that when the locomotive manufacturing is complete, the camber will be greater than or equal to zero. In the improved process of the invention, the camber may be set smaller or even to zero, because the shape of the locomotive is more precisely controlled during assembly. During assembly of a monocoque locomotive, the final goal of assembly will often be to have very little (i.e. zero to 2 millimeters) camber of the finished locomotive after assembly, equipping, and finishing.

In prior art methods of assembling the underframe, a support rests underneath the underframe and large masses are set on the top of the underframe to hold the underframe down. The masses may be moved or changed during assembly of the underframe as the underframe distorts during assembly. Such a process is relatively imprecise and is limited by the space and weights available.

According to the present invention, the underframe is held rigidly in a fixture to achieve a completed underframe that is near the desired final shape. Such a process allows more precise control of the shape of the underframe. This may be accomplished by strapping the underframe to the fixture and adjusting the rigidity of the connection using, for example, turnbuckles. By constraining the underframe during assembly using this method, as much as about 100,000 pounds of force may be applied at several points on the underframe. Thus, the underframe may be fixed into a final shape during the assembly process.

Such a fixture is shown in Fig. 17. The underframe fixture 74 includes a floor plate 122 that is made of concrete and has fixturing components positioned on top. The fixturing components include reaction beams 124 that support the fuel tank 76 (Fig. 7) during assembly. The reaction beams 124 are so named because they do not in this case exert a downward force on the underframe, but merely position the fuel tank 66 and react to the load placed on the underframe by turnbuckles in the fixture. The underframe fixture 74 further includes a plurality of hard stops 126 positioned on both the left side and the right side of the underframe fixture 74, offset from the central longitudinal axis of the locomotive. In a preferred embodiment, there are eight hard stops, a pair for each section of the underframe other than the fuel tank 76 (i.e., the first cross member 78, the second cross member 80, the first end assembly 82 and the second end assembly 84, as shown in Fig. 7). The hard stops 126 are used to position the underframe 72 at several points, and may be shimmed in order to precisely set their position. A plurality of turnbuckles 128 are used to clamp the underframe 72 against the underframe fixture 74. The turnbuckles 128 are positioned in proximity to the hard stops 126, such that the underframe is held to

the hard stops 126. Additionally, turnbuckles may be positioned at the ends of the underframe fixture 74 in order to secure the end plates to the floor. The turnbuckles 128 are fixed at one end to the underframe fixture 74, such as to the I-beam on which the hard stops are mounted, as depicted in Fig. 17. The turnbuckles are fixed at the other end to the underframe 72 with the use of pads. The pads (not shown) are essentially plates of steel that can be positioned within or on top of the underframe to more evenly distribute the tension stresses to the underframe. The pads may be connected to one end of the turnbuckles by putting a hole in the center of the pad, passing the turnbuckles through the pad, and fastening a stop on the end of the turnbuckle that will not pass through the hole.

Such pads are useful because the forces exerted on the underframe can be significant. A single turnbuckle is capable of exerting as much as about 100,000 pounds of force. Thus, the force should be distributed over an area.

Upper Body Fixture

As illustrated in Fig. 18, the upper body structure 51 may be set within a fixture. The purpose of setting the upper body structure 51 within a fixture is both to more accurately fix the shape, such as the camber, of the upper body structure 51, and to maintain the upper body structure 51 such that it may subsequently be mated to the underframe.

The fixture for the upper body structure 51 may thus comprise a fixture for setting the lower edges of the upper body structure 51 as well as a fixture for holding the outer walls in structural alignment and for lifting the upper body structure.

As shown in Fig. 18, the fixture base 62 is a plate that substitutes for the corresponding mating area on the underframe. If the top of the underframe,

or the top of the fitting structure on the underframe, is made horizontally flat, then the top of fixture base 62 is set flat. The dimensions of the fixture base are designed to correspond to dimensions of the corresponding mating area. If a cambered upper body structure is desired, then it may be preferable to modify a flat fixture base 62 by shimming the center portion above the ends.

The squareness and trueness of the sidewalls and roof sections may also be set relative to the fixture base 62. The dimensional accuracy of the upper body structure may be verified by measuring the position of the cant rail 130, which is a rail that runs longitudinally along the intermediate section 55 of the upper body at the junction of the sidewalls 100 and 102 and the roof section 104.

It is more important to maintain the squareness and trueness of the upper body structure 51 if, as shown in Fig. 18, the upper body structure 51 comprises the intermediate section 55 of the upper body 50 (Fig. 3). This is because the interface with the rest of the locomotive body is along 2 vertical planes (at the front and the rear of the intermediate section 55) and along a horizontal plane (at the bottom of the upper body structure). As previously described, such interfaces may include lap joints or fitting structures. Nevertheless, some fitting of the upper body structure may be required along 3 planes. If, on the other hand, the upper body structure comprises the entire upper body, then the interface with the underframe will be substantially along a single horizontal plane. Thus, less fitting of the upper body structure to the underframe may be required.

The upper body structure fixture may further comprise a lifting fixture 132. The lifting fixture

132 is designed to lift the upper body structure at the cant rail 130. Preferably, the lifting fixture attaches at the openings 134 in the structure such as

doors and inlet openings, because they are more rigid than the surrounding sheets. Such a lifting fixture 132 may be designed solely to lift the upper body structure, as shown in Fig. 18, or may also help to fix the position of the sidewalls, as shown by the rib fixture 96 in Figs. 9 and 10.

If a lifting structure is used that does not give structural support to the upper body structure, then it may be preferable to supplement the fixture base 62 with internal fixturing, such as internal braces 136. Such internal braces 136 may include turnbuckles fixed to the cant rail 130 and running diagonally across the interior of the upper body structure, to the opposite corner. Such internal fixturing would impede access to the inside of the upper body structure, and thus make installation of internal component assemblies more difficult.

It will be appreciated by those skilled in the art that the invention contemplates many different variations on the processes shown and described, and may be applied to different structures. For example, the invention includes a method of manufacturing a monocoque upper body that may be applied to manufacture of a bus body as well as a locomotive body. Such other similar structures are within the scope of the invention.

Other types of fixtures are possible according to the invention. For example, the fixture that holds the underframe may be mated to the rib fixture to form an inverted rib cage.

Further, the processes of the present invention may be applied in such a way that the whole locomotive may be simultaneously be manufactured. For example, it would be possible to provide an underframe fixture and an upper body structure fixture that are fixed in the positions of the final assembly of the locomotive. In this way, the entire locomotive may be

simultaneously manufactured while the dimensions of the locomotive are set.

Various features and advantages of the invention are set forth in the following claims.