Tsukuba Express Elevated Rail Set

If it's any help, there's a Doctor Yellow set in the current lineup that is similar, with the auto transfer track. But it uses blue tracks and isn't elevated.

Link to item on Amazon.co.jp

Or search for "自動のりかえ駅とドクターイエローセット"

Actually R-22 is a better match.

If you want the elevated tracks only, you can buy them in packs of 2.

For curve tracks, type Tomy R-27 in the ebay search. For Straight tracks, type Tomy R-26