As per previous quotes - there are compromises between Bachmann's tooling (based around the original Peppercorn / BR build) and the spec of Tornado (Network Rail loading gauge / Menningen built boiler etc). To be fair they've done a good job of sorting the obvious changes (tender / whistle), but it's not realistic to retool the boiler and smokebox to reflect every change made for "new build". Also you're wrong about the Cartazzi arrangement, it's as good a solution to the problem as I've seen in OO, and looks close enough to a "real" A1 arrangement in my eyes, as well as being able to navigate less than prototypical curves. TL:DR - even skilled kit builders would struggle to get something to look as good as the Bachmann model.