Do it, the hardest part is making that first cut. Out of the dozen or so steamers I have I can't think of 1 that hasn't seen the Dremel. Masking tape around the area will help some, just don't be heavy-handed. Files can finish the spot nicely.
My most trying "operation" was removing fluting from n OK Engines passenger car body to make a Seaboard Air Line Sun-Lounge car, something I would not do again. Here's some photos of my efforts and sitting next to the GGD Sun-Lounge that was done a while back:
Here's 2 Williams/Samhongsa brass USRA 2-8-2 I modified to represent 2 different classes Seaboard used:
They started out the same, but 411 in the foreground was heavily modified to a SAL Class Q3 whereas 492 in the background was left mainly intact as SAL Class Q1
Steady hand and good lighting will get you going.
I Dremeled off the Bellpaire firebox hump from one of my RailKing 2-8-0 also:
I did Dremel thru the boiler but some JB Weld fixed the hole, backed by a piece of styrene:
Really surprised by the detail on these RailKing engines:
