First, I would have bought the track if it was available as you can get about 12 pieces for $5 when you buy the "Straight Track Pack" and it takes about 3-4 hours to print out each one. The problem is that none of the sites or stores have it in stock or you may find the rare pack on Amazon, but instead of the normal price they want $15-$20 for it. This is actually why I originally bought my 3D printer.

I scoured the internet trying to find a track to print that worked with the TrackMaster version of Thomas the Train. I was able to find a few things, but no simple straight track. This is the result of my search, I made my own (for my toddler). It is the same width and height as the original track, but it's about 12mm longer or so. I'd alter the design again, but this works for me. If you want to make a revision, go for it. :) I've also tried the following slicers: Cura, Slic3r and CraftWare in order to find what prints it the best. I have found the Cura engine inside Repetier-Host to be the best so far (the CraftWare one has about an hour left to print, but looks promising). The point here is about the supports. The hardest part of this print are getting the supports set up right so it's easy to clean. I had to alter the base Cura settings to increase the distance between the support and the model, otherwise it was too much of a pain.

Printing: I put the track bottom on the base. You could flip it upside down and possibly reduce your supports, but I didn't because I wanted the top to look pretty...

So, use supports. Other than that, have fun printing it. :) Like I said, I'm still tweaking my slicers to get the best print/cleanup.