Ok, so I have yet another question about signals I hope someone can answer. How is the interface between route and speed signal territory handled? A great example of this is Stevenson, AL where the ex-Southern NS joins CSX heading to Chattanooga. The NS line which joins CSX and runs on trackage rights to Chattanooga, has a single 1 over 3 signal guarding the interlocking. Under route signaling, the best aspect would be diverging clear, under speed signaling the best aspect (at this location - medium speed switch) would be medium clear. How is this situation handled here and elsewhere? Would that signal be a speed-signal with the distant to that also being a speed-signal (so trains would get approach medium, then medium clear/approach)? Or would that still display the NS's route-signal aspect with a timetable instruction giving the speed over the switch(es) (so trains would get approach diverging then diverging clear/approach)?
There are lots of places where the two types of signaling come together. When I was in passenger service for BN in Chicago is one. Burlington has route signals, but it transitions to PRR speed signals coming into Union Station. I don't recall how the last Burlington signal would relay what the first Pennsy would show.
I can think of several ways this could be handled. One might be for some timetable instruction for a non conforming aspect. The last Burlington route signal may show an Approach Diverging. Knowing the possible aspects and indications of the first PRR signal is part of route familiarity. This would be how the engineer knew if the first speed signal would be a Limited, Medium, or Slow speed. Burlington used Approach, then Restricting for some equivalent of a Slow speed route.
I would have to be qualified on the location which you mentioned. My examples are just some ways which the situation could be handled. Some locations exist where nothing is 100% perfect. D&H has a siding, which has another control point about 2000' past the end of the siding. A train to be held at that next controlled point would get Advance Approach, Approach, and Stop, if routed on the main. If going via the siding it gets Medium Approach Medium, Medium Approach, and Stop. Because of the short distance between the end of the siding, and the next signal, the engineer must have hold.There is no indication which can say that you must be at Medium speed, but stop at the second signal. It is just part of knowing the characteristics.