When I had to remove the boiler and cab to replace the gears, there were three large screws. Two under the cab near the rear and one on the top in the bottom of the first dome behind the stack. There is a fourth small screw that connects the linkage from the cab to the reversing mechanism on one side of the engine, that also needs to be removed. This is very small (larger than the four on the pilot, but it is easily lost and it is non magnetic.
It will take some work to lift the boiler assembly off the chassis. Separate it from the cab end. There is a lip under the front of the smokebox that holds it in place. There will be some sounds as it comes off. They sound worse than they are, at least nothing appeared broken. When you reassemble you will need to catch the front of the smoke box on the chassis and then rotate the cab end down. This will take several tries. At least it did for me.
Chuck
It will take some work to lift the boiler assembly off the chassis. Separate it from the cab end. There is a lip under the front of the smokebox that holds it in place. There will be some sounds as it comes off. They sound worse than they are, at least nothing appeared broken. When you reassemble you will need to catch the front of the smoke box on the chassis and then rotate the cab end down. This will take several tries. At least it did for me.
Chuck