GIGABYTE,
Unfortunately what has happened is you have purchased FasTrack from a couple different generations. The newer FT is made differently than the older, there are several other threads showing the exact differences in the track engineering, which leads to the difference in rail height.
The best thing you can do is send me all the 1st & 2nd Generation FasTrack and purchase the newer lower quality FT for your own layout.
Only kidding! However the next time you purchase any FasTrack take a piece with you and make sure you are purchasing the same generation FT, so everything matches correctly. Messing around trying to match the different generation FT just causes trouble down stream as you build, however some people use a Tack Hammer and tap the rails almost perfect and then screw every thing down even, and use them.
For your knowledge the 1st generation FT was the very best, it has a Black Center Rail, and will never work apart when running your carpet central. The 2nd generation will match it perfectly, but has no Black Center Rail, and stays together nicely also. The later generations have different shaped rails and cheaper made road bed, and will not stay together, without being screwed down, or clipped or zip tied together.
The Black Center Rail FT is very troublesome stuff, send every Bit of it to me, when you find it.
PCRR/Dave
1st & 2nd Generation FT and FTCC Switches, the good stuff!
Our over head ceiling layout is all 2nd Generation FT and all Trains run smoothly on it, Tin Plate included. The Bar Top and lower levels are a mixture of 1st and 2nd generation FT giving a very smooth running layout, all with FTCC Switches.