The Gravity Group announces a wooden shuttle coaster: The Switchback Railway

Maybe a turntable, ala the two train wacky worms? Don't forget, the train also has to be turned around.

No, it doesn't, actually. The "circuit" is actually just the station, lift, first drop and switch, then back to the station. From the switch, there's a spur where the train goes forward than backward.

Gotcha, thanks.