Initial comment: If it's truly drawn the way you intended, there would need to be a very dramatic slope for those 2 return loops at the top left.
As shown, the grey track needs to go from above the red track to under it in a space only roughly the diameter of the curve. Actually it's worse than that now that I look again. You go from below to above to below, all in that small area.
That seems way too steep.
Unless you did that accidentally, and intended one reverse loop to be entirely above the other?
{edit:now that I re-read your description, I guess it was an error with the software. You did say the red was supposed to all be below, my bad for typing before I re-read that part. That might be OK since you have that really long run from the switch on the top right to transition to a lower level.}
-Dave
