When my grandson was 6 i started building him a model railway in my front bedroom, over a period of 5 years it took over 3/4 of the room. He is nearly 15 now and has other interests so a couple of yeas ago i packed it all away for him to have when he grows up and has a place of his own. It had quiet a lot of rolling stock, 40 single engines, several complete train sets, 100+ wagons & coaches, electric turntable, stations, buildings etc. It was good but nothing like the one on the link below, truely amazing.
This is the world's biggest train set.
Covers 1,150 square meters / 12,380 square feet
Features almost six miles of track and is still not complete
Miniatur Wunderland *** official video 2012 *** largest model railway / railroad of the world
http://www.youtube.com/miwulatv