The voyage videos were made using a Customized version of NoLimits, and was made by the Gravity Group.
The Goliath and El Toro videos were both made by Keith of badnitrus and the last I knew he used 3D Studio Max.
No limits can be picked up from www.nolimitscoaster.com/ for a meere $29.99, and you'll be able to create decent coaster in very little time. Of course they only offer a limited number of coaster trains. Don't worry they have most of the major ones.
3d studio max, on the other hand will cost you around $3500.00 (yes thats thirty five hundred dollars) and have a very steep learning curve. You won't be able to load this program up and expect to make what ever you want right away. If you are interested in 3D modelling, a much more reasonably priced program is Blender www.blender.org. It's free open source software, and it's just about as powerful as 3DS Max or Maya(which are industry standards). Once again programs like this aren't dedicated to the task of creating rollercoasters. They are all purpose 3d modelers, so you could make what ever you want with them. Since they're so powerful it will take a bit of time to learn.