A routine to toggle invisible track (on / off) just a thin line visible when setting it to see exactly where it is would be great. I'm currently creating a layout which needs a lot of invisible track, it's quite difficult to get right.
Try some of mine 39134:101050, a nice blue, you won't have any problem seeing mine yet its totaly invisible in driver.
My invisible road is 101049 also blue, set for no cars since its used on my road crossings.
I made my own. Thin orange line in surveyor and invisible in Driver. About as easy a gmax project as there is. A great starter project. I use it for dual gauge sg/ng3. Custom track splines are another fairly easy project to start out on.