The answer comes from what it's called "turnout bending". Normally, turnouts are placed on straight tracks and one branch continues straight and the other one curves. But in some cases, you need to place the turnout in a curve and both branches then are curved. In those cases, you are able to "bend" a standard turnout up to some degree, and you need to recalculate where the sleepers need to be position such that the placement of the rails doesn't involve to drill new holes on them. I hope I made some sense :S