Benny,
Welcome to the forums.
By editing the track, do you mean to physically change the track to something else?
If yes then you'll need to edit the asset in Content Manager. It is highly suggested that you duplicate (clone) the asset first, and this is a requirement for built-in assets.
If you just want to find out what the asset is, go to the mouth of the tunnel and use the track asset selector find out what the track/tunnel is. Once you've selected the track/tunnel, the asset will appear in the list ready to be used again.
John