“Thomas the Tank Engine” styled wagon

My little guy, 18 months at the time I started this, was a big fan of Thomas the Tank Engine. With his plastic store-bought wagon broken due to a damaged wheel, I figured we could make something far more entertaining out of some SPF planks.

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First, a 2′ x 5′ frame (outer dimensions) using 2×4’s, waterproof wood glue, and pocket holes via a Kreg jig. I initially had planned to add a steering mechanism via a steering wheel, pair of shafts, universal joint, and a rudimentary Scotch yoke (below). A metal 1/4″ threaded shaft would join the front castors I used for wheels, with a metal loop bolted onto it, and the far end of the steering mechanism connected to a flywheel. Given my kid and his friends asking for train rides while the project was barely, built, I figured there was no need for it.

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Next, some paint, putting down some 1×6 planks for a floor,  and affixing some support posts with heavy brackets and pocket holes.

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Now, time to add some side panels…

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Bench seats, doors…

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Now for the biggest frustration in the whole project, the cosmetic “tube” at the front of the train. I ended up running some 1×6 planks through the table saw at 22.5 degrees, and gluing the sections together with a web ratchet. Took a few tries to get everything aligned properly. The front cover panel was some 1×6 planks glued together along the edges, and cut into an octagon using a miter saw.

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Everything painted, assembled, and ready to go. I bolted on a heavy 2×4 to act as a “lock” for the doors, so they couldn’t open while the “train” is in motion. I left a small gap near the front, right above the black “tube” portion. I’ll later add either a piece of plexi glass or a headlight there.

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Finally, (not shown) I added some simple electronics to implement a pull-down trapeze-style handle to make a loud horn sound effect. Just a pre-built audio evaluation board which I connected to a tiny 8R speaker, and a large snap-action switch which connects to a piece of paracord to activate the audio functionality. All the interconnections were done with 0.1″ crimped cables using kits purchased from Hansen Hobbies. The Digikey bill-of-materials (BOM) for the electronics is included below.

  • Snap-action “on-mom” switch:
    • http://www.digikey.ca/product-detail/en/omron-electronics-inc-emc-div/VX-53K-1C23/Z5185-ND/5237059
  • Battery holder with lid:
    • http://www.digikey.ca/product-detail/en/mpd-memory-protection-devices/SBH331AS/SBH331AS-ND/275299
  • 8ohm speaker:
    • http://www.digikey.ca/product-detail/en/soberton-inc/SP-1504/433-1106-ND/3973690
  • Audio EVM board:
    • http://www.digikey.ca/product-detail/en/nuvoton-technology-corporation-of-america/ISD-COB1730/ISD-COB1730-ND/1228823