Tuesday, April 6, 2021

Better Commonwealth Trucks for Your President's Choice Steamer

Back in late 2006, like many Canadians, I acquired for $50 a President's Choice Mehano trainset that was released the before in Loblaws and Provigo groceries around the country. On the advice of a local hobby shop owner who demonstrated the mechanical virtues of the locomotive, I went to the supermarket and picked up a set for half its original price with the intent to once kitbash it into a more realistic version of locomotive CNR 5703.

Left: modified truck, right: original truck

While the model was crude, it wasn't bad and Mehano had a decent reputation for good drives at a fraction of the price. We ran the locomotive until it no longer fitted our era of interest then back on the shelf it went.  Regularly, I would look at pictures and drawings of a real CNR Hudson. The biggest issues were the wrong cab and the Vanderbilt tender. This one was particularly unrealistic as it was based on an old Pemko design which had the motor into the tender. Due to that poor design choice, the coal bunker was large and clunky. Many decided to simply swap the Mehano tender with a Bachmann Spectrum Hicken one, however, this line of tenders has been discontinued long ago and they are now sold at ludicrous price. I thought it wouldn't make any sense to pay so much for another stand in, albeit a better one.

After taking some measurement, I came to the realization I could splice two kitbashed Mehano tenders together and make a much more prototypical CNR Vanderbilt tender. However, the big challenge was the trucks. While fairly accurate, they were much longer than the trucks used under CNR tenders. I had two options againt: source new prototypical trucks or bash the Mehano ones... Only recently, Rapido started to produce good Commonwealth tender trucks and I purchased a pair. But I still wanted to try the kitbashing route because it could be useful in the future and I thought the Mehano trucks were well designed and would be easier to attach back to the underframe.

Top: original Mehano truck, Bottom: modified truck

So yesterday evening, I disassembled a Mehano tender to harvest a pair of trucks. Before any work started, I tested how the plastic reacted to solvent cement. If it was Delrin, the project would stop right there, but if it was styrene or a similar plastic, I could proceed. I knew IHC heavyweight passengers cars - which were also Mehano products - had styrene trucks that could be glued together. So my guess was they used the same plastic. Imagine how happy I was when the plastic started to melt!

The first step was to use a jeweler saw and remove the sideframes from the truck assembly. It was done quickly. Then, I removed the brake shoes and kept them for further use. The big challenge with the sideframes was to harvest the parts with holes in the casting, remove extra material to shorten the lenght and glue everything back together. It went surprisingly well and using a paper jig with key measurements, I was able to make sur everything would fit the prototype dimensions. On my first trucks, I unfortunately glued the holes to close together and they don't look that great. But on the second one, the spacing is much better. I also added a 0.5mm thick styrene strip behind the sideframe to reinforce the assembly.

Next step was to remove the lugs on the truck wheel cover and shorten it to the right length while keeping the screw mounting holes intact. I also did the same with the truck wheel housing, using styrene stripes to reinforce all the spliced joints.

With that step done, I cut new square styrene mounting blocks and glued them on the wheel housing. Mehano sideframes were attached to the wheel cover, but I felt I would get a much stronger assembly by gluing the new "pins" on the wheel housing. It was also a good way to clear space to the brake shoes. Each block was cemented with the metal wheels in place to make sure everything could run without friction.

Finally, I modified the brake shoes. Since the trucks were shortened, the brake shoes where closer. I cut the excess material, spliced them together, remove extra material and added a small mounting block in styrene behind the shoes to provide a larger surface for a stronger bond. They were then cemented under the square mounting blocks holding the sideframes.

After a few hours, the kitbashed trucks were completed and surprisingly sturdy even after all the splicing required to get there. They roll perfectly free on a piece of track. The next step will be to hide the seams with some putty and sanding, then modify the copper electrical pickups that are housed within the trucks. I also started to add brake cylinders from my spare box following the prototype.

I still consider the Rapido trucks to be much better detailed. However, the way the wiring is done, I feel my modified Mehano Commonwealth trucks will be easier to attached to the modified tender. I'll keep the Rapido trucks for another project where they will be more useful. Now, it's time to think about bashing the tender for 5703. As for my new Mehano CNR 6060, I'll probably modify its tender truck too, but scratchbuild its tender from a PVC pipe. I almost purchase a Van Hobbies brass tender for it, but felt it was overkill for a cheap and unprototypical locomotive! Building stuff is much more fun!

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