If anyone thinks model Loco manufacturers put thought into designing and producing a Loco which will or only will match its prototype rating is sorely deluded……they make a chassis, it pulls half a dozen coaches, it’s fine, that’ll work, whether it’s a 0-6-0 Pannier or a Deltic is irrelevant to them, I have an old Thomas the Tank which will pull seven or eight coaches with ease and a Flying Scotsman that struggles with that same load.
Nah….sorry….to much faith in the Blue, Dark Blue and Red boxes.