I assume that the loco you are looking into is this:



If so, I noticed that it does not have a decoder or sounds and costs around $200.00 CAD, probably around $170US.

For about the same money, you can buy a Marklin 36243 that has a a digital decoder with a lot of great sounds. (You could even add a smoke unit to it but then you would have to make some modifications. There has been an involved discussion on this forum about it.) Here is a picture of it, it is a tad smaller, about 3/4 of an inch or so:



Steam locos do not normally travel very fast and a Roco R2 track should do just well for you. I run my Roco Ice Train on Roco R2 track and there is no problem. Please note that Roco starts at R1, so that Roco's R2 is the equivalent of Marklin's R1.

I cannot tell you how good of a runner the Roco loco is, if by that you mean how fast it goes, since I do not have one. The Marklin loco is pretty slow.