I got the most significant part of the this project completed this evening. The frame chop.
The Milwaukee Road GP38-2s had a VERY SMALL fuel tank. So, in order to model one accurately, the fuel tank MUST be cut down to the correct size. The Milwaukee reduced fuel capacity on many of it's locomotives throughout it's epic history. I have read in several publications that it was to reduce the overall weight of the locomotives and thus lessening damage to the rails, which in many sub-divisions and branch lines, were often in disrepair.
Here is a good prototype shot showing how SMALL the fuel tanks actually were:
This is not the prototype that I am modeling.
Here is the original Athearn BB GP38-2 that I purchased used:
And here she is after the frame chop: