Many wise comments here about seeing as many different types of track as possible. Also, really think about your goals with the layout and realistic timetables for achieving them (especially if you're new at all this like me).
Several have commented on their dislike for or problems with MTH Realtrax. However, when one has had a fairly positive experience (as I have), I think it's worth posting.
An MTH RTR set was what got me started in this enjoyable hobby. I enlarged the oval to a 4x8 which of course involved buying more track and switches--by then I had more dollars invested invested in Realtrax. After seeing some larger layouts, I realized that I wanted to expand beyond the 4x8 and was able to secure a 25x12 area in our basement.
My goal then was to get a layout planned with some trains actually running on it to "test" it -- in a fairly short period of time. So sticking with the Realtrax was the way to go for me, accepting its limitations (no curved switches, etc.) compared to what so many consider as the gold standard: Gargraves track and Ross switches.
On the other hand, the attached roadbed made it fairly easy for me to actually "build" the layout on the floor so I could see how the flow of the track plan actually worked. Granted, not having curved switches limited our design options.
Anyway, here are a few photos of the layout progress to date using MTH Realtrax, a product which has really worked out pretty well for me.
I'm still looking for ideas as to how to best fill in the south dogbone area--but that should be in a separate post I think.
When I first started running trains on this layout, I, too, experienced some rail misalignments which caused some derailments. However, with the right pliers and just a tidge of bending of the rail I solved those alignment issues.
I've attached a a few photos and a video. Among my goals at the outset were: two mainlines permitting several trains to run at once and with direction reversing capability for both the outer and inner mainlines, all this without any grade changes (at least for now).
PS: Sorry for the jiggles on the video--will use a tripod next time.