I've been busy on weekends and an hour or two on weeknights working on my personal project - the little rail truck. Last week it was at long last ready for a test drive. I called Phoebe, my grand daughter, who has been waiting twelve long years for a test drive.
The throttle was still jury rigged, the drive train chain was not yet tightened, and a few other things yet to be done but I was confident the little rig would power it's way down the track without difficulty. I jumped into the cab and Phoebe into the sidecar. The vehicle was stable - despite Phoebe now being almost adult size and weight. The goal was to do a couple test runs un and down the completed track and then do a video pass - which I would post to the blog for all to see.
Things did not go quite as planned. The drive chain was far too loose and jumped the sprockets continually. Then as we approached the first corner things went awry. The tandem rear wheels bound badly as the front of the car negotiated the corner. My design simply wasn't going to work. Phoebe took it all in stride for she knew I would come up with a solution.
As we used the rig back towards the shop I puzzled how to do a fix. By supper time I had the solution.
The answer was to pull one of the axles in the rear. It didn't take long. Once the axles were pulled I cut off the bolts and welded in a new set. The single axle was then bolted into place, entered under the fender. I was almost happy but thought things looked a little sparse. It was time to do a little research...
I decided I would add a single spring to the back axle and a arch bar suspension to the front truck. Using some historical pics from the web I designed the steel components in EnRoute. The pieces would be cut from 3/8" and 1/8" plate steel. The screen grab below shows the file for one side of the truck. It took a couple of hours to assemble, weld and grind each piece.
As I worked I was amazed at how fast and efficient the Plasma cutter made the operation. Everything fit perfectly and little grinding as necessary. This little all steel vehicle has been in progress for twelve years and much of it was done without the benefit of our MultiCam CNC plasma. Things are much better now!
The springs and archer setups are actually non-functioning as the axles are supported by pillow block bearings off the frame. The spring assemblies look massive and fill in the fender space nicely. Visually and in actuality they add weight to the lower half of the chassis.
There are still a few more details to add to the chassis of the rail truck but I am pleased with the result. It should function a whole lot better on the rails. In the next couple of days I'll put it back on the track and call Phoebe for another test drive. Hopefully all goes well. Stay tuned...