While watching the Rochelle webcam just now as a BNSF train was heading westbound, I wondered if there might just be a UP train waiting in the wings. I waited a bit, but none appeared. That does beg the question: How long after a train clears the circuit does the signal clear for movement on the other line?
It’s been decades since I’ve had to see this professionally, but my memory suggests that it’s not very long…possibly just as soon as all conflicting movement clears the circuits (I suspect that if another BNSF train were approaching the crossing from the other direction, a waiting UP train would not get the lineup).
I can’t find any orders to that effect, but there are grade crossings on both sides of the diamond (several of them to the east–behind you as you look through the webcam) that should be kept open as long as possible.
At times when I have actually been at the Rochelle RR Park I have witnessed exactly what you are speaking of. A BNSF train comes thundering through the diamonds and (what seems like) about thirty seconds later you can hear the gates come down for an approaching UP train that has been waiting “in the wings” as you put it. This is most often seen when the UP train is an eastbound as there are (as previously mentioned) several grade street crossings to the east on the UP that must be kept open and thus the westbounds will “wait” much farther east of the diamonds than the eastbounds do as there is only one grade street crossing to the west of the diamonds to contend with and there is enough track length west of that crossing to hold a sizeable train.
It depends. If the dispatcher unlines the route before the train has cleared the circuit then he/she/it/they can line an opposing route straight away. But if she/it/he/they wait till the train has cleared the circuit before unlining the route then they/it/she/he has to wait for a few minutes before a new rote can be lined. This is a safety feature of the signalling system.
It’s been my understanding that the Rochelle diamond is “first come, first served” and isn’t tied in with anything else not necessary to control traffic across the diamond.
Assuming only two trains (one from each RR) in the mix, it sounds like once a train clears the circuit the crossing train almost immediately gets a green. I was wondering if there was any sort of time delay (like sometimes exist on switches). Apparently not.
It has been noted by others that trains crossing the diamond sometimes appear to slow down so as to hold the crossing for another of their own that may be passing or meeting them on the other track.
Thanks for the insight. Other comments and experience are certainly welcome!
I can only relay what the “locals” in Rochelle told me when I was there.
The signals are not controlled by dispatchers, they are first come first serve. The train entering the control circuit first gets the light and if they linger in the circuit they can in fact hold the tracks for a movement in the other direction to enter the crossover and then, in theory that movement could linger and allow yet another train from the first direction into the circuit and on and on. In reality when the circuit is clear, it becomes available. In the event of a “tie” entering the circuit, which the locals say does happen, then a crew member must walk up to a manual button and get the light for that train, first crewmember to hit the button gets the light.
Don’t know if this explains it but it is the way the local folks explained it.