I have a question about flex track. I'm using Atlas code 80 N scale. With sectional track you can put a test layout on top of your board before you put down roadbed and lay out and ballast your track. Now with flex track on curves it flexes out unless it's glued or nailed down. I have not done this yet, but when I do a practice/test layout before I layout the roadbed how do you keep the track from flexing out of curves and so on? Are the rail joints able to keep the track in place?