Simple terrain question

[gs83]

I'm sure there's a very simple way to do this but playing with the terrain tool i cant for the life of me figure it out. The square below is 3 different tracks, and im trying to fill in the gap with terrain. How do i accomplish this?





Click to drag causes this:

 

[zaxxon]

Click and drag 4 times: one on each of the tracks. Then join the anchors to close the gap. May be the corners will give you problems, but working on them a little you can get a good result.

 

[gs83]

Click and drag 4 times: one on each of the tracks. Then join the anchors to close the gap. May be the corners will give you problems, but working on them a little you can get a good result.

I get stuck here before i make a total mess of it. Should i be removing the section on the outside of the turn which overlaps?

 

[zaxxon]

Click and drag from one corner to the next. And stop there.
But you can go on with what you have, just deleting overlapping triangles.