Maybe the origin for Red Snapper can be like if Topham sends one of the R46 engines to America, because the Bigg City RR, where his son works, may need a shunter or something like that. Or Topham sends blueprints for the R46s to the BCRR and his son makes some modifications, like bigger splashers, outside cylinders, etc. leading to Red Snapper. More of his type werent needed, and as he was a prototype, he was kept around. Just an idea.
Amazing job man like you head cannon on the universe. And in my au design thomas was a lbscr d1x tank engine just the way it looks just looks like thomas to me.
In my headcanon I have two reasons why thomas is short 1 take gordon for example if he looks the way he does then that's what his brothers and sisters looked like same for e2 2 he was part of the short e2 line up from 1913-1914
