Engine truck: two steps forward, one step back

Obviously, things were going too well. Parts were literally flying off the frets and attaching themselves to the frame. I was hopeful of actually hitting my deadline.

The optimism continued as I folded up the the engine truck. Even tacking the bottom chord onto the side frames worked reasonably easily, despite being a flawed design in the first place. Sure, I etched one of the fold lines on the wrong side, but that was easily corrected with a brass shim over the plastic flexure.

When it came to gluing the flexure into its metal sandwich, I found myself wishing I had designed a cunning assembly jig (perhaps incorporating those pesky bottom chords) to keep everything square. But with appropriate prayers and burnt offerings, even that seems to have worked.

Engine truckWhen I dug out the wheels, I remembered that Past Rene never did drill the axle holes. He should know better than to add cosmetic spokes before the engineering is complete. Fortunately, he left behind a split collar to chuck the wheels in the lathe.

One went okay. The other three could not withstand the pressure of drilling; those brass-stainless solder joints that gave me so much trouble the first time around gave way like my willpower around cookies. One of the centres was so traumatized by the approaching drill that it flung itself from the lathe and remains cowering in some dark recess of the heavy shop.

Engine truckIt was back to the drawing board. I’ve now designed an improved wheel that incorporates a shelf to support the centre during drilling. Creating new larger centres will take an evening at least, probably pushing me past the deadline for display.

4 thoughts on “Engine truck: two steps forward, one step back

    1. On a 4-4-0, the engine truck serves as one point of suspension, while the drivers serve as the other two. Some British modellers equalize the forward drivers with the engine truck, which enables the driven rear axle to be rigid. However on a Canadian eight-wheeler, there is too much air for that approach.
      Having said that, the truck flexure enables a small range of independent vertical motion between the two sides of the truck.

  1. Hello Rene,
    I saw your comment on Stephen Gardiner’s blog regarding his visit to Fillmore Avenue Roundhouse. If you find that you will be in the Toronto area and would like to operate Fillmore, please let me know and I would be happy to have you over.


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