I have a #4 W/S code 83 HO turnout that has developed a bow in the center. There is ample clearance on the ends, but the center is up about .014". I layed the turnout on my table saw and it still was up in the center. End to end.
My question today is how best to correct it? I could sand the bottom of the ties on the ends but then it would need shims to elevate it to the adjoining track. I could also glue it down just eniugh to hold it down and still be able to remove it later. Type of glue is questioned here.
Try bending it back down in the middle by holding the ends and pressing on the center with your thumbs. Start with a gentle press, check it on the saw top, then exert more and more pressure until the turnout is flattened out.
I set the ends up on 1/2" blocks and held the center down to table level for 30 seconds. Then I repeated the procedure. It now seems flat and I will monitor it as it seems to want to return to its original state over time.
If the rails are bowed and you just glue the ties down, the rails will want to bow up and pop out of their spike heads. What you did will probably fix it.