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

The individual parts of the Heisler trucks are difficult to photograph because they are hidden by other parts of the locomotive as well as the gears inside the truck.  Without the good fortune of finding the middle truck off the locomotive and partially disassembled on a photo trips in June and July, 2004 I doubt if I would have ever figured out the shape of some of the castings.     The trucks are complex so I've split the description into two parts to keep the download time reasonable while presenting many photos.  The sides and bolster are discussed in this first part with the remainder of the components presented in Part II.  The wheels, rods, gears and brakes are described elsewhere.

Truck Side:  This is the left side of the middle truck looking front to back..  The side is a large casting.  It looks like sleeve bearings are used on the axels.   The little cover on the top edge directly above the axel provides access to a bearing oil reservoir.
This is the same left side as in the previous photo but the rear axel area rather than the front.   The hose is part of the forced lubrication system --- in this case supplying oil to the bearing that is part of the gear case.  I'm lifting the cover for the axel bearing oil reserve in the hollow part of the side.   The blue stuff I think is called waste and is used to control the oil feed to the bearing.
There is a cluster of 4 springs that rests on a shelf cast in the center lower part of the side. The holes in the top edge of the side secure the cap and upper cross pieces.
This shows the end of the rod that is part of the lower cross bar.  The side can swivel on this rod.   There is a cap below the rod that holds the rod to the side.  That is a grease fitting on the upper part of the rod end.  The brake shoes hang from the truck side.  Discussion of the brakes are deferred to the brake section.

The drawing above accurately describes the outer surface of the truck side.  The inner surface has  considerable variation with lips, cavities and webs and no attempt was made to capture these inner side details on the drawing.  

Axel Bearing Caps:  I assume those are sleeve bearings on the axels, probably similar to the bearings used on the truck shafts.   This photo shows the left front corner of the middle truck.   The view is looking down on the axel.  The bearing cap is on the under side of the axel.
This is the bearing cap.  It is a casting held in place by a bolt at each end.   Ball bearings will be used on the model.  The ball bearings have a  different profile than the sleeve bearings so no effort was made to make a drawing of the Cass 6 bearing caps.

Frame bolster.  Before looking at the truck bolster it is a good idea to look at the under side of the mating frame bolster shown on the right.  The cylindrical part that hangs down fits in the top of the truck bolster.   The pads that normally ride above the truck bolster rollers are resting on the wood blocks
Truck Bolster:  The truck bolster is another large casting as shown here.  The ends of the bolster rest on the top of the spring clusters and are held down by the caps.  The cylindrical part of the frame bolster fits into the round cavity with the bottom of the frame bolster resting on the bottom of the cavity.   The rollers at the ends of the bolster prevent the frame from tipping to the side.   The bolster is bowed to make room for the shafts to pass underneath.
This is a close-up of one of the rollers.  The rollers are tapered with the mating pads on the frame bolster wedge-shaped.  The casting under the roller is hollow with an opening directly under the roller.
This shows another opening to the hollow interior.   The large pin has a cross pin on each end.   One of the mechanics at Cass said that the pin will retain the truck if the locomotive upsets.  He said that wasn't the case on a shay.
There are legs in the four corners that slide up and down in channels in the truck sides. This photo shows one of the legs.
The corner just to the right of the tape measure is where one of the bolster legs fit.  Pieces of the cap form the third side of the channels for the bolster legs.

The drawing above shows the truck bolster.  No attempt was made to show the interior cavities.  I've shown more dimensions that usual on this piece to assure myself that the pieces fit together.  For example, the bolster must fit with the sides, the caps and also match up with the frame bolster. And, the  bolster must position the frame at the correct height.      

This is a good point to break.  The truck is finished in Part II 

All the truck drawings are combine in one file that can be downloaded from the Drawings page...\..\Drawings\Drawings.htm