what are good types of paint to paint passenger cars

I just want to do a color change on the Madison cars. I'm making my own polar express heavyweights that don't cost 180 dollars each! Lol  the engine i just want to paint part of the boiler I think.. 

But I think I might have to repaint the tender because it's the MTH rf and p and there's a lot of lettering on it and I bought some pe decals.

Also do you know if once I apply the new decals, do I need to spray a clear coat on them so it won't be noticeable that they are a decal? Or does it not matter? 

Thanks so very much!

It's very difficult to answer your question. Are you going to remove the original lettering, strip the whole shell, or just disassemble and paint? I would suggest at the least making sure the original lettering  will not show through a new coat of paint ( use your fingernail or a toothpick to feel if the lettering is raised or lowered compared to the car body), a good cleaning in soap and water, and perhaps even mild solvent wash, followed by somehow scuffing or roughing up the original paint a little to give some "tooth" for the new paint.

Hardware store paint is hit and miss on plastic. Some will work, some won't. I would suggest using a plastic safe paint such as Scale-coat 2, or an over-the-counter paint that specifies it will work on plastic. 

i was wondering if you think acrylic would work and be durable? I like the fact that I could take my PE Lionel baby Madison to them and they could do a pretty exact match on color. I think the acrylic paint is a water based paint but It's more durable than regular latex paint. It's what is sometimes used on kitchen cabinets. I would rather use a more conventional hobby paint but I do like the idea of them doing an exact paint match.