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Great to see the Master (Elf) behind his creation with a proud smile Thanks to you both - Ron and Chris.
Hi Derek,I think this picture will help, a render of what the final inside of the machine will look like. At the point where the backstay from the A-frame attaches to the frame under the floor is where the boiler starts, so its wieght is behind that point. Also, there are two very large water storage tanks, one on each side of the boiler, that are used to refill the boiler during use. The coal pile is behind the boiler, on the right end of the picture. All of that will add an awful lot of wieght to the back of the machine, bringing the center of mass well behind the front tracks. The machine started out with a working weight of 120 tons, when it was mounted on railroad wheels. The addition of the tracks must have added to that, since they added the track frames and tracks front and rear, the large supports out the side, and another large gear block underneath.Looking up the weight of crushed stone, I see one reference to 2700 pounds per cubic yard, and this shovel had a 2-1/2 yard bucket installed, so that would be in the neighborhood of 5400 pounds, which is quite a lot to have it that far out in front of the machine in the bucket, but even calling it 3 tons, that is a whole lot less than the 120+ ton machine behind it. Obviously it worked out, since the machines were a huge success for many years!You do have a point about the balance - before I added the gear train and hoist engine, I had to have a big block sitting on the rear deck to keep the model from tipping itself onto its nose from the weight of the boom assembly. Now, even without the boiler, it balances well behind the front tracks, and needs a fair bit of lift on the rear deck to tip it.As for side to side, the front tracks have a span of over 21 feet, to keep it from tipping to the side when the boom is swung over.
Swallows of what, to carry it? (husk or no husk, >hic<)I certainly don't think there will be any stability issues with the model. There sure weren't any with the full size big shovel units in normal use. I have seen old photos of shovels in trouble from overload, ground collapsing under the tracks or the rails under railroad ones, collisions with other vehicles, and being stuck under landslides or rockslides, but never due as far as I know to instability of the machine itself. Glad to see Bucket Bob and Ratchet Ronnie the elves are behaving themselves in the photo with you!