I would love to build a giant O-Scale train layout. Full send...mountains, tunnels, rivers, a city, multiple freight and passenger lines.
Oh my god is that expensive and time consuming. I don't have the money or the time, and if I ever do have that much money or time I'll be old and won't have the energy anymore.
Oh well. I'm super good at making sandwiches though. So I got that going for me...Which is nice.