Back Frame Rear Spacer

    The rear spacer shown at left includes the drawbar pin mounting features and the drawbar tensioner pad.  In the prototype locomotive the tensioner pad butts tightly up against a mating pad on the tender and tensioning wedges are inserted to put the drawbar in tension removing any slop that might otherwise occur.  The drawbar is located in a slot just below the tensioner pad.  

    One of the drawbar pin mounting holes is visible at the left on the illustration.  The illustration is a jpeg output from the Alibre Design program and is scaled at 1/2"=1'.  

    The front and rear spacers are shown in position on the back frame assembly, one of three that make up the bulk of the chassis frame.  Bolt detail was added to the sides of the back frame where they will appear on the prototype.  Subsequent details may hide much of these, but it is easier to add them now.  

    The overall chassis frame is shown next with some of the components that will eventually be attached to check for fit.  The rear chassis is located over the rear truck and provides the pivot attachment for it.  A #5 screw is planned to provide the pivot attachment for the truck.  The details for the back chassis section are not yet complete.  Other sections to be added include the rear sill that attaches the rear of the cab, the rear firebox mounting sheet, the rear truck spring attachment mounts, the front truck spring attachment points and the equalizer mounts.

    It takes about two nights of working time, about 4-5 hours time to design the rear spacer due to the level of  detail included.  The remaining details are expected to take arond 3 to 6 hours each as well.  Consequently the entire back frame assembly is not likely to be completed until early to mid November.  By that time the BFB-3000 3D printer is expected to arrive and fabrication of parts can begin.