Who needs a model railroad system? Just buy the Treintafel (Train Table), an erstwhile regular-looking table with a set of railroad tracks carved right on the top.
Introduced by Woet, a collaboration between Destino and Furniture Design by Tomm Velthius, the playtime furnishing is a fully functional table, too, provided you don't mind a desk with multiple lines carved onto it. Of course, you'll probably want to shelve the trains before plopping the laptop down, lest end up with a never-ending train-to-computer collision (and avoid eating -- you'll get crumbs stuck on the tracks).
Fully handmade, the Treintafel measures 70 x 50 x 45 cm with an all-wood construction. The railroad tracks, which run throughout the entirety of the tabletop, are hand-carved, too. There are plenty of flat areas, as well, so you can set up mountains and towns and serial killer dumping grounds to go with your winding train system.
A removable drawer tray sits under the top, where you can hide your tiny choo-choos, along with the rest of your model accessories (you know, in case you're having a girl over and would like to maximize your chances of looking moderately adult). If you're too lazy to open the drawer, you can also opt to just dump the items into the hole in the middle of the table surface (it comes with a cover, like a desk-manhole, of sorts).
The Treintafel Train Table is available now on a made to order basis, priced at €449. Not sure if the trains are included with the price, but they can supposedly throw in toy locomotives from Brio and Ikea upon request.