There's 3 easy ways to make the boiler overhang less apparent with less than visually ideal curves:
1) Watch your layout operations at eye level. After all how often do you watch real trains from the vantage point of a helicopter like the overhead shots above anyway?
2) Watch your Big Boy only on straightaways. Look away at something else while it's in curves.
3) Conceal your curves with scenery, like tunnels, trees, or buildings.
