This is a new signal that went in on the UP mian line in Salem, Oregon. It's a few hundred feet north of the depot. Does anybody know what the lower lamp indicates? I have never seen it used. This is single track with no turnouts.
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I know nothing about UP signals but I wanna take a shot to see if I come up with a answer. Could the lower signal head change an idication from "Restricting" to "Stop". It's just a guess, the picture has me curious.
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It is a block signal (indicates by a number plate). Since it is all single track and the train looking at the signal is not in a pocket, it probably cannot display an absolute stop. It could tell the crew to take the siding at the next siding, but I suspect that it has a different function, possibly indicates the aspect of the next signal.
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The upper head functions normally as trains pass all day long. I have never seen the lower signal active. I thought it might have a future function in PTC but the head is not turned away from the tracks. It must have a current function. Of the hundreds of new signals installed in this year in this area, this is the only one I've seen like this. The next siding is more than a mile ahead. I also thought it might indicate some thing to Amtrak stopped at the station, except there is not another one for southbound trains. It seems unique.
Here in Colorado, along the Denver & Rio Grande ( now UP ) The lower lamp is a lunar white that will allow a train to pass a red stop signal at a slow restricted speed, ready to stop, when following a train going up grade. So that a heavy freight wont have to stop and not be able to get going again on a steep grade. My understanding is that if the lower lamp is not on, then the red stop signal becomes an absolute stop.
Anybody, ..... Let me know if this is not correct.
Steve
Well, a "Stop and Proceed" Signal. As a block signal (as marked by the number board) it cannot display a "Stop and Stay" order.
steve24944 Here in Colorado, along the Denver & Rio Grande ( now UP ) The lower lamp is a lunar white that will allow a train to pass a red stop signal at a slow restricted speed, ready to stop, when following a train going up grade. So that a heavy freight wont have to stop and not be able to get going again on a steep grade. My understanding is that if the lower lamp is not on, then the red stop signal becomes an absolute stop. Anybody, ..... Let me know if this is not correct. Steve
Signals without number plates are defined as being Absolute signals and are the only signals that can display STOP. Signals with number plates are not Absolute signals and cannot display STOP, their most restrictive indication is generically known as Stop & Proceed - each carrier has their own definition of how this applies on their property and some carriers do not require the train to stop but only proceed at Restricted Speed
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NP Red MORE iFORMATION The upper head functions normally as trains pass all day long. I have never seen the lower signal active. I thought it might have a future function in PTC but the head is not turned away from the tracks. It must have a current function. Of the hundreds of new signals installed in this year in this area, this is the only one I've seen like this. The next siding is more than a mile ahead. I also thought it might indicate some thing to Amtrak stopped at the station, except there is not another one for southbound trains. It seems unique.
A second, lower head is usually going to be a signal in advance of a controlled switch (CTC or manual interlocking instead of one that is exclusively hand operated by people at the switch) to let the train know that it will be taking the diverging route at the next, or is some cases, the second upcoming signal and proceed accordingly. When the switch is lined for the diverging route, that lower head will probably display either a green (green could also flash), yellow, or lunar. The color used will depend on what the allowable speed is for taking the diverging route and if that route is signalled beyond the switch.
It is possible that the lower head does indicate something for an Amtrak train stopped at the station. Since that would be a local situation outside the scope of system rules, it would be noted in the special instructions of the employee time table for that area.
I'd guess though it's more likely that the signal is an advance indication of what's going to happen at the next siding.
Jeff
Your mention of the siding one mile ahead is a pretty strong argument that Jeff's given you the correct answer. I suspect that the lower light will be either yellow or green (there is only one light on that lower head, right?).
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From Union Pacific Railroad, System Special Instructions,
Effective Wednesday, April 7th, 2010...
Page 165, with number plate, rule 9.2.13, aspect with the lower single signal flashing has indication of "proceed at restricted speed, not exceeding prescribed speed through turnout when applicable."
As Jeff pointed out, it most likely protects the siding by informing crews they will be taking a diverging route into the siding.
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It could be for a yellow or lunar light (approach deverging/approach restricting) like the above post suggested informing crews that there are going into the siding.
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Thanks for the Welcome! I'm just kind of looking around a bit. MOE
Approach Diverging(yellow over yellow) going into the siding and
Approach Ristricting(yellow over lunar) deverging to a turn out
mopar_tx Thanks for the Welcome! I'm just kind of looking around a bit. MOE Approach Diverging(yellow over yellow) going into the siding and Approach Ristricting(yellow over lunar) deverging to a turn out
Approach Restricting is proceed prepared to pass next signal at restricted speed, but not exceeding 15 mph. Usually the diverging route at the next signal would lead to unsignalled track.
There is one place on my territory that we get an Approach Restricting but usually don't take the diverging route at the next signal, which is usually an Approach (yellow over red). Since we hardly ever do take the diverging route (which leads to an old yard ladder and connection to another main) some become complacent. One time we were on an adjacent track while another train was comming up along side us. They called the App Restr over the radio but weren't expecting to take the (rail)road less travelled. When they got to the next signal they were lined through the ladder. The signal at the far end (it's a short section of track) is an absolute and must have had a Stop indication because as they were going by us, we heard their air go. Evidently they had to big hole it (plug it, spike it, shoot it, or any other euphemism for throwing the train into emergency) to get stopped before that absolute signal.
Sorry folks. I was thinking about this question I posted and it just dawned on me what the answer is. Two city blocks before this signal is the last turnout at the north end of the Salem yard where it joins the mainline. When they installed this new mast, they removed the old one and they also removed the signal located at that yard switch two city blocks before this. The lower head must simply be for that switch. One mast replaces two. What confused me is the fact that it is located so far from the actual switch. It can be seen from that switch. Is this common to have a signal a long way from the actual switch?
That light is a lunar white light which restricts train speed to no more than 20 MPH. They put it there because you can not have a lunar light with those 3 fixed signals. Some of the older signals had a color wheel which had all the colors including lunar.
I would have to say they put it there because there is a train station in a block where the signal is typically red (probably from the yard up the road switching cars on the main line). It would allow the train to proceed after stopping even if the signal was red. This would save time as the train could proceed and stop at the station while the other train could get out of the way instead of the train just sitting at the red signal waiting for the train to clear the block and then go to the station.
You don't see lunar signals too often. Most of the time if there is congestion you will get a flashing red. Draw bridges are a good place for lunar signals as you want the train to travel at a good clip but the engineer has no idea when the bridge will go up either. You will probably see that lunar signal every time that train comes to town or not at all. Lunar signals also typically have large lights. The lens are sometimes 3 times the size of a normal lens.
In the terrtory that I'm in we get the Approach Restricting signal in a few places, two of which is when we are leaving CTC and entering TWC and I think in one area of Houston from one Subdivision to another. We get the get the Approach Diverging everywhere in Houston.
The Approach Restricting signals we get do lead to a deverging route to either a siding or a turn out. MOE
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