Thank you! So you mean the couplers on the actual trains won't match from Thomas to the US Prototype, so a Thomas engine won't pull the US cars, but they can all go on the same track?

Hi, I am a foster parent and I have a child who is about the turn 8 who is an avid train enthusiast. He is asking for an HO scale Percy for his birthday. He already has a Thomas but his actual HO tracks and the power supply is broken. If I order a generic HO set and a HO Percy will they be compatible? I want him to have what he wants for his birthday and I want it to last but when I was adding up the Thomas and Friends HO set and the Percy I started having chest pains. Please don't judge my lack of knowledge and correct terminology, until a month ago I have only had daughters, 🤦.