Your progress isn't that bad as you think, considering your lack of time recently. Don't hurry with those wheels, making wheels is always nerve-consuming business. You said it right, after it even such bad kit like the BP train is simply piece of cake. Funny, here it was right the opposite. The BR52 locomotive made me so mad that I finished no less than 10 wheeled thingies after it just to restore my mental health
(yes, this is the main explanation of my recent output, Elliott!)
Keep those wheels rolling! Never mind on road or rails.