How do you attach curved track to baseplates? At first it appears that it can't be done because the sleepers are all at an angle and don't line up with any of the studs on the baseplates.
Actually it can be done fairly easily by raising the track by one plate above the baseplates. To align to the sleeper angles, use the small 2x2 turntables. The diagram below shows where turntables fit reasonably well (shown with red circles). A few 2x2 tiles are used in other locations so that the track is fully supported (shown as red squares). The ends of the curve obviously align correctly but should still be supported with a 2x8 plate to avoid twisting the curve.
Note: these positions are pretty good and the best I could find, but they are not exact.