It would be nice if there was some kind of "Junction missing lever between Junction 653 and Junction 593" or something like that... But we know how N3V likes to make improvements.
Sometimes its not as obvious as you think for finding the right junction either - ie, not necessarily along the route you'd think the AI should take, or even one of the better alternates. Case in point, I was testing my route last night, there's an "old" Y near the engine house that used to lead to a south branch and is out of service - I had thrown some End-of-track signals at the Y near the south junction and hadn't bothered to put a lever on it since it wouldn't be used and I assumed it was protected behind the EOT's. Test running a steamer throw the Y (Comes out of engine house forward and runs backwards to the interchange past the other side of the Y)...
Wouldn't you know it, the AI had a fit because it couldn't use the south side of the Y to turn the engine and head to the interchange forwards... Even though the junction was past the EOT's which would've prevented it from using the junction anyway it still wanted the lever there so it could turn the engine around (and end up running backwards all the way up to the other end of the track 15 miles from the interchange)... I had to split the splines there and only connect the one side of the "disused" Y to keep the track shape.