As it was related to me by upper management of the D&S mechanical department, the main reason #476 hasn’t been repaired is that with four K-36's in service, they haven’t needed her.
As I understand it, the problem isn’t as serious as some folks believe. The cylinders are attached to the frame by a number of fitted taper bolts, and two tapered keys. The keys are meant to take the thrust from the cylinders. As I was told, the keys were lost while the engine was still owned by the D&RGW, and run for a period with just the fitted bolts taking the load. This caused the fitted bolts to start working in their holes and the cylinder block to start working (i.e. moving back and forth, not rigidly held) on the frame and under the smokebox. The keys were replaced, but with the fitted bolts now loose, the cylinders still worked.
What is required is to remove the old bolts, ream the holes true, make and fit new bolts and keys in both the frame and smokebox. This will be a time consuming process (I could see it taking one man a couple of months), but in the scheme of things, it's not that big of a deal. The most disassembly required would be to remove the lead truck, and possibly the bottom of the smokebox. Whatever other machinery work that may be required would be normal wear and tear, and unrelated to the cylinder issue.
As far as the boiler goes, the survey process will be exactly the same as every other engine on the roster, no more, no less, and they all passed. It will be stripped, UT’ed, stresses calculated, and repairs made. It’s pretty routine these days.
