Hi!
While we love the animation and the incredible detail, it's a pain to keep on the track and seems very delicate. Our son just sneezes on the thing and it derails. But, it's easy to put back on. Also, the connections from car-to-car (not the physical connectors, but the electronic current carrying one) is very difficult to line up and plug in every time a train car derails.
We have this set, plus additional track and three more cars. There are lots of expansion pieces available.
p.s. - you can go to the mfr web site at www.newbright.com to order replacement parts. We were told by several large hobby stores in Atlanta that they no longer carry these trains b/c the company doesn't back its product well. Our main connection did the same thing as the other reviewer's and we just got a soldering kit and used solder to get it back together. Also, after just one year, our sounds buttons on the controls no longer work, and we've taken it all apart, cleaned it, etc. and still not working at the touch of the buttons.