Scale Detail Parts on a Semi Scale Locomotive

I recently posted a thread about detailing an MTH RK PRR K4s with PSC parts.  I had the same concern, but came away pleased with the result.  Pictures included so you can judge.  

In the end it probably depends on how compressed you semi-scale engine is.  The MTH RK K4s is about 93% of scale.  Scale parts are exaggerated, but look good to me.

Scott:

Nice job on the K4. It looks great! I've always liked the RK model, but didn't like the lack of detail on the front end. Problem solved! As to my Berk, I will say it is quite small. The combined length of the engine and tender is only 19" vs. 26" on it's scale counterpart. I wish Lionel gave height dimensions, I'm more concerned about how a scale headlight and mars light would stack up on the front end. I'm not super strict, as long as it looks good to me, I'll live with it. Even just envisioning it, I can't see it looking all that bad. I think at this point I need to buy the parts and see for myself. 

Suggestion:  What is the most prominent part or element of this project that matters most to you?  Buy that part(s) and see if it/they work for you.

There's no point in buying a bunch of parts before you have satisfied yourself that the element that matters most to you will be acceptable.

I've done a fair amount of bodywork modifications on LIONEL PW F units using scale parts from P&D, PSC, etc. and they work, but those cab diesels' profiles are very close to scale in most dimensions except length.  Your situation is much different, though you might ask for someone to measure the boiler width, etc. so you have less guess work.

I added some scale parts to an MPC Berk, and it came out OK.  The key is probably to decide on the essentials, as Carl suggested.  I added number boards, whistle, the front-mounted bell, and the side-mounted feedwater heater (had to track that one down; finally located a leftover from a PRB project by John Smith, which he was kind enough to provide me).

The decals are full-scale-sized, too, but they don't seem to overwhelm. The effect is just enough to strongly suggest MoPac's smaller class of 2-8-4s.

Looking at the project, I can definitely say the headlight, mars light, and flying number boards take highest priority. They will make the engine look like a true NKP berk. I'm planning on ordering all three items from Lionel as parts used on the scale Van Swearigen berks. I have a feeling it may look a little large but as long as the essence is captured and it doesn't look too out of place it's fine with me. I just ordered paint and a few of the details today - look for a construction thread in the near future. 

palallin posted:

I added some scale parts to an MPC Berk, and it came out OK.  The key is probably to decide on the essentials, as Carl suggested.  I added number boards, whistle, the front-mounted bell, and the side-mounted feedwater heater (had to track that one down; finally located a leftover from a PRB project by John Smith, which he was kind enough to provide me).

The decals are full-scale-sized, too, but they don't seem to overwhelm. The effect is just enough to strongly suggest MoPac's smaller class of 2-8-4s.

I always wondered if someone did any kind of work on one the PW/MPC tooling. Nice!