I designed this for my son as he's a huge train fanatic (he's 4yrs old) and Big Boy is his favorite. He asked me if i could make one for him. So I took a few dimensions from one of his other Brio trains and tried to model this as close to the original Bigboy and keep the aesthetics of Brio.

I used the wheels designed by SCHWEINERT.COM where you can find there models here.

So shout out to @danielschweinert for the inspiration.