This week I have an extra post to slip into my step-by-step build of an N Scale A-B-A Ready-To-Run set of Alco C-855 locomotives. Back in July I posted part 3 which covered the chassis preparation procedure, you can find it here. However I missed something so in this post I’ll cover what it was and how to do it. My apologies to anybody who has been following this build along with me. I will update part 3 which will make this post redundant but for now here it is.
You may have noticed I regularly recommend test fitting things as you go and I should take my own advice. The chassis below has been prepped to fit into a C-855 A unit and at the cab end you can see how the top chassis section has been notched to fit into the narrow nose.
But the lower section doesn’t fit all the way in and a test fit before I assembled the chassis would have told me that. In the picture below I’ve removed the lower chassis section and placed it into the shell. As you can see the inside corners of the nose clip the shell.
However this is easily fixed by cutting two notches in the chassis section as marked below. Each notch is 3.5mm (0.1377“) wide by 2mm (0.0787“) deep leaving a nose of about 6mm (0.2362″) wide.
I cut these out using my Dremel tool and cutting disc.
The bottom chassis section now fits into the shell.
This extra notching is not required for the C-855B chassis as it doesn’t have a nose. Next, as I have disassembled and resembled the chassis, I’ll test them for running smoothness and any binding in the drive shafts. Then it’s on to the shells which will be in a later post.