Cass 6 Truck Part II
Nelson Riedel, Nelson@NelsonsLocomotive.com
6/30/2004, last updated 04/08/2006

The truck side and bolster castings were discussed in Part I.  The remaining parts of the truck excepting the gears, brakes, wheels and rods  are discussed here.  The gears, brakes, wheels  and rods are described in other pages.  

Cap: The caps are also castings. This photo  shows the top of the cap; the side that faces out is laying on the floor. The caps fit over the bolster.  Bolts through the two holes draw the cap down onto the side.  As the caps are drawn down, the bolster is  forced  between the two sides and the springs are compressed
This shows the side of the cap that faces the inside of the truck.  Studs on the cross bar clevises go through the holes on each end and then through the truck side.  The caps must be drawn all the way down before the clevises can be installed.  The part of the cap that hangs down forms part of the channel for the bolster legs.
This shows the installed cap.  The two studs with double nuts closest to the camera go through the holes in the previous photo.  The top of the cap curves to the inside to pass behind the roller.  The vertical bolt through the cap is partially obscured by a smudge on the camera lens
This shows an installed cap from a slightly different angle.  This time that vertical bolt is clearer --- no smudge

This is one of the most difficult drawings I've done.   I kept getting the photos backwards, etc.  I think the model will be much plainer.   

Upper Cross Bars: The upper cross bars connect between the top of the truck sides via clevises to control the separation of the sides.  There is also a cross bar at the lower part of the truck under the bolster that has the same purpose.  Together, the three bars keep the sides nearly parallel and at a nearly fixed distance apart.  The control is not absolute because the sides are permitted to rotate around the axis of that lower cross bar to accommodate variations in the track.      

The photo above shows one of the upper cross bars that had been removed from the middle truck.   The piece in the lower middle of the photo is part of one of the caps that was also on the floor.   These bars and the clevises are both steel, not iron castings.    

The photo above shows one of the upper cross bars on the front truck.  The studs on the clevis pass through holes in the cap and the side.  The bars bow up like the bolster to allow the shaft to pass underneath.

A close up of a clevis.  This  photo was taken to backup the dimensions  I recorded  (sometimes I can't read my writing.)   Those are studs that thread into the base of the clevis.   The studs are ~ 1" diameter.   After looking at this photo I realized that I didn't measure the pin OD.  The pin is definitely bigger than the studs so I drew it at 1.5" OD --- close enough.

The drawing above describes the upper cross bar and the clevises.  The dimensions have been checked against the cap and side drawings and they seem to fit together.   The 39.5" overall width when added to the width of the part of the cap through which the studs pass (2 @ 1.5") gives a total of 42.5".  The inside dimension between the bolster legs is  43.75" giving 0.25" slack.  There is 0.25" slack in the other direction too.   Based on the roughness of the measurements, the fact that things seem to fit together is more due to luck than skill..     

Lower Cross Bar:   A Heisler marketing brochure boasted  " A patented 3-way swivel--- perfectly flexible in its action, while rigid and sturdy in construction --- holds  each wheel  in contact with the roughest track.   Every wheel is gripping the rail, carrying its full share of the locomotive's weight, and delivering it's full share of the hauling power."
The lower cross bar is central to the swivel feature but very difficult to observe on the assembled truck.  The partially disassembled middle truck was of no help --- the extra gear hardware on that truck made it even more difficult to observe. This photo shows the end of the lower cross bar.  The end is cylindrical so that the side can pivot around the cross bar are shown in the previous sketch.    There is a cap below the cylinder which holds the cylinder and side together.  That appears to be a grease fitting on the upper part of the cylinder end..
This photo of the front truck shows part of the lower cross bar beginning at the inside of the truck side and extending  to about the middle of the truck.  The bar bends down to give room for the pinion shaft, shaft bearing and gear case.
There are two swivels associated with the lower cross bar with each axis noted on this photo.   #1 is the swivel axis between the cross bar and the side which allows  one side to rotate with respect to the other side.  #2  swivel axis allows the gearbox to rotate with respect to the cross bar so that one wheel of the front axel can be higher than the other wheel on the axel.
This  photo is a pretty clean shot of the lower cross bar of a smaller Heisler.  Part of the swivel that links to the gear case is still bolted to the cross bar.  This is the lower cross bar for the middle truck so the swivel is offset to one side to give room for the line shaft on the other side.   The front and rear truck lower cross bars are symmetrical.
I was frustrated trying to get a view of the underneath of the lower cross bar so I tried putting the camera on the floor and pointing it at the under side.  This photo is the result .  The bars, clevises and pins on each side are part of the brake system.   Part of the  cap which holds the bar to the side is visible the upper middle part of the photo.   The bar is clearly a casting with  interesting bends, crevices and  webs.

The above drawing of the lower cross bar was made primarily from the photos so it is only approximate.  The diameter of the ends were measured.  The positions of the shoulders on the end cylinders were computed based on the other truck drawings.    The dimensions of the mount for the gear case swivel and the underside are estimates made from measuring photos.    This is the lower cross bar for the front and rear truck.  The lower cross bar for the middle truck has the gear case swivel offset to one side as shown in a previous photo.

The above photo shows the brake plank that is between the lower cross bar and the inside axel on the front and rear truck.  The plank serves as a mount for the brake cylinder (cylinder hangs underneath).  The extra gears on the middle truck require a different mounting arrangement for the middle truck brake cylinder.   This plank is not a structural part of the truck so it's covered with the brake components. 

This finishes up the Cass 6 trucks.  All Cass 6 Truck drawings are in one file that can be downloaded from the Drawings page.