In my case, the GTR project is in the second category. My big problem is that I have very little understanding of what I'm doing (early 19th century compound locomotive) and have limited access to information. To be honest, I started the project without thinking too much, knowing I would find my away around arising issues. Worst, while the Bachmann locomotive is indeed a good starting point, the way it is built isn't compatible with a prototype with low running boards. This is going to be the most challenging part, even if almost invisible.
Today, it came to my attention I goofed on two key parts. I first used wrong measurements to make the cab window. All week long I found them very weird and badly proportionated. This evening, I opened my CAD drawing with 719 pictures and verified the results against my HO scale version. I was 2 mm off! Not wide enough and not by a small margin. So I'll have to enlarge the windows and make new parts. Well, it's not a bad thing since my window frame were oversized and badly attached to the cab walls.
The second problem is more important. Wayne pointed out my cylinders weren't correct. In fact, he was polite because they are total bogus. He kindly sent me good reference pictures and the conlusion was easy to reach: a GTR compound had two cylinders on the fireman's side and a single large cylinder on the engineer's side (with a flat top). It was also a good occasion to find out my running boards were also wrong.
I'll have to start again on these 3 elements. It could be disappointing, but in fact, it is motivating. Sure, it's a "waste" of time, but I had fun making the wrong parts and it was about doing what I had never done before.
There's no shame in going wrong when working on a project, except for abandoning. Except for brass locomotives, I've rarely seen people modelling compound cylinders. I knew when I started the project that kitbashing a "correct" Grand Trunk compound Consolidation as built by Schenectady wouldn't be a walk in the part. At some point, I could have abandonned the idea of making a Russian iron version in favour of building a later rebuilt with normal cylinders and black paint scheme. But I feel it wouldn't have been beside the point of modelling something unique: big early Canadian steam in Russian iron.
By the way, I got my hand on a stash of old CDS dry transfer including Grand Trunk, Intercolonial, Canadian Northern, Canadian Pacific and Temiscouata. All are for freight cars. I'm not sure if they are in good shape, but I thought an alternative could be to scan the lettering and make custom decals out of it.
Old Time Decals
As you know, I made HO Grand Trunk locomotive artwork. I also intend to make a set for Canadian Northern.
I also redrawn the Central Vermont pre-wafer sans serif lettering artwork. However, most CV locomotives used the serif lettering. Using commercial fonts is a no go and I prefer to redraw each letter from actual pictures to be prototypically correct. If some of you are interested (and I know some are), high resolution pictures of CV locomotives (preferably side views with minimal distortion) would be very useful. The biggest challenge is to have enough photos to have an example of every numbers from 0 to 9. It is interesting to note some CV locomotives kept the old GT-inspired paint scheme until the late 1930s.