BaltACD In it's final days the PRR started putting Red on the Horizontal aspects and Conrail continued the process. Amtrak added the other colors after it took over the NEC.
http://broadway.pennsyrr.com/Rail/Signal/aspects_us_pl.html
And, Amtrak also eliminated the middle light for most aspects, apparently except for the lower head (white) under Rule 291 - Stop and Proceed:
http://www.railroadsignals.us/signals/pcl/
No doubt the reason the PRR started - and Conrail continued - installing Red color aspects was that without them, a crew couldn't technically run past a Red signal - an amber or Stop, signal, yes, but not a Red one . . .
- Paul North.
My understanding is that Amtrak's "Position Color Light" signals are retrofitted signals that were already in place, and there are no new installations or replacements using this style.
I know for a fact that the NEC Shore Line between New Haven, CT, and Boston uses Type G "tri-light" color light signals.
The railroads (among others) are all about eliminating complexity and introducing standardization.
While CSX has been leaving B&O CPLs up (as opposed to aggressively replacing them), they aren't fixing them if they break - a "Darth Vader" goes up instead.
That's not to say that the CPLs couldn't be updated with modern electronics and LEDs, but that's where standardization comes in.
Imagine if motorists had to deal with different systems of traffic lights from state to state?
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
tree68The railroads (among others) are all about eliminating complexity and introducing standardization. While CSX has been leaving B&O CPLs up (as opposed to aggressively replacing them), they aren't fixing them if they break - a "Darth Vader" goes up instead. That's not to say that the CPLs couldn't be updated with modern electronics and LEDs, but that's where standardization comes in. Imagine if motorists had to deal with different systems of traffic lights from state to state?
denveroutlaws06actually we already have different styles of traffic lights from state to state.
While there are different makes and models of traffic lights, and some states have different approaches in their application, by and large you'll find that pretty much everyone follows the Manual on Uniform Traffic Control Devices.
So while the traffic lights in Omaha may look different than the traffic lights in Orange, NJ or Ojai, CA, they all operate the same way, and mean the same thing. A driver doesn't need to be "qualified on the territory" to cross state lines.
Exceptions (like the light on Tipperary Hill in Syracuse, NY, which has the green on top) are rare.
I ran Google Earth and entered "Tipperary Hill in Syracuse, NY" in the search box and it listed "Tipperary Hill Traffic Light", so it must be of some note to be in their database already. Using Street View you can see very clearly that RED is on the bottom and GREEN on the top. Strange! WHY?
Semper Vaporo
Pkgs.
Semper VaporoUsing Street View you can see very clearly that RED is on the bottom and GREEN on the top. Strange! WHY?
The name should provide a clue as to why green is on top.
Apparently the traffic light folks got tired of changing it back to red on top some years ago, so they just left it the way the locals kept changing it to...
Sorry, as per usual, I am clueless as to why the locals (apparently) change it to green on top.
Tipperary: Irish...
More here.
Belleville, Illinois, was a railroad town that had green on top on their traffic signals in the 1950s, when all other cities has red on top.
People who were red/green color blind and went only by which light was illuminated may have caused traffic accidents in those days.
A little more on the antipathy towards having green at the bottom of a traffic light. What I was told, many years ago, is that when the son-in-law of James II, William of Orange (a Netherlands province), became king of England and Scotland, he invaded Ireland and subdued the Irish. He also invited Englishmen and Scotsmen to move to Ireland, and many did; today their descendants are called "Orangemen"--and there is much antipathy towards them.
In the ordinary cycle of traffic lights the green light at the bottom is overcome by the yellow or orange light above it. Even though the green at the top is displaced by the caution signal, that the yellow, or orange, is below is not as bad as having it above.
Johnny
tree68 While there are different makes and models of traffic lights, and some states have different approaches in their application, by and large you'll find that pretty much everyone follows the Manual on Uniform Traffic Control Devices.
Don't come to Georgia. The DOT is adding a blinking amber light arrow. Haven't figured it out and media inquiries have gone unexplained. My take -- Advance diverging approach ? or advance approach diverging ?
blue streak 1 Don't come to Georgia. The DOT is adding a blinking amber light arrow. Haven't figured it out and media inquiries have gone unexplained. My take -- Advance diverging approach ? or advance approach diverging ?
We have those in Michigan. They've replaced flashing red arrows and mean complete your left turn when traffic is clear. People are still confused over them.
Norm
Here in the wilds of Iowa we also have that blinking yellow left arrow with a big sign that says left turn yield on flashing yellow... same function as the sign for the green light that says left turn yield on green. Dunno what the difference is, other than a make work project for Highway Maintenance workers to change all the lights and signs.
Yes, the traffic control vanguard in Salt Lake City also has this silly aspect. Perhaps it has not been sufficient to simply instruct people that you do not make a left turn in the face of oncoming traffic.
For some time, we have had the adjunct two-light (green arrow and full disc green) with the sign indicating that you should not make a left turn in the face of oncoming traffic when you see a green disc. I was introduced to this when I was driving in Greensboro and High Point, N.C., in 1982 and 1984. It took me a little while to figure the thing out. I much prefer the signal that shows a green arrow when it is safe to turn and a red arrow when you should not turn. Of course, this signal is used only where there is a system that senses the presence of traffic in a left turn lane--and the adjunct signal also depends upon a sensing system.
Semper VaporoHere in the wilds of Iowa we also have that blinking yellow left arrow with a big sign that says left turn yield on flashing yellow... same function as the sign for the green light that says left turn yield on green. Dunno what the difference is, other than a make work project for Highway Maintenance workers to change all the lights and signs.
Perhaps the highway traffic signal folks are just now starting to come to grips with an issue that the railroads settled a long time ago (not all in the same manner, though): Should the signal be a 'speed' allowed or restricted) signal, or a 'route' allowed (or prohibited) type of signal - or perhaps even a hybrid of each ?
And the highway people have to deal with a "universe' of drivers/ users of varying capabilities, whereas the railroads can be selective in who they choose and train them accordingly.
Then too, how do the highway signals distinguish between moves that are:
Paul_D_North_Jr Absolutely prohibited Steady Red - full disk or arrow Conditionally prohibited Usually by signage (left turn yield to oncoming traffic on green) Conditionally permitted Varies - some, like "right on red" don't have a signal as such. Flashing red can be compared to "stop and proceed," except you have to make sure there's no other traffic. Absolutely permitted Steady Green And the impending change between one of those signals to another (i.e., the Yellow Caution signal, whether flashing or not ) ? Note below.
Stop me if I've said this....
At one time, traffic lights went from red to yellow to green, as well as green to yellow to red.
Apparently it made for some interesting situations at "ground zero."
Highways have a problem that the railroads generally do not - it's almost impossible to provide an advance warning of an upcoming signal, and since the signals cycle based on traffic flow (even those on a fixed timer kinda do so), the lead times are necessarily short, especially at urban speeds.
I've seen some advance warning signal/signs for traffic signals on roads with 55MPH speed limits. Typically these would be placed where a curve in the road prevents seeing the actual traffic signal from a distance.
I also have vague recollections of seeing a similar warning signal/sign for a RR crossing on US 212 just northeast of Joliet MT.
- Erik
tree68 At one time, traffic lights went from red to yellow to green, as well as green to yellow to red. Apparently it made for some interesting situations at "ground zero."
Traffic signals in Germany and some other European countries are still that way - red to yellow to green and green to yellow to red. Many motorists there treat the yellow as a "get your engine revved up and ready to blast off!"
cacoleTraffic signals in Germany and some other European countries are still that way - red to yellow to green and green to yellow to red. Many motorists there treat the yellow as a "get your engine revved up and ready to blast off!"
Or getting set to "jump" the green, which sets up the interesting situations with those trying to beat the red...
Erik - I've seen those as well. Usually they're coupled with a yellow diamond sign and serve only as a warning of the upcoming signal, whereas an approach on the railroad carries specific restrictions with regard to speed.
When in Buenos Aries it was like being at a drag strip when the red dropped to yellow.
There was an experiment where they were adding white strobe lights to a red signal. looking at this page:
http://en.wikipedia.org/wiki/Traffic-light_signalling_and_operation
It looks like they are not allowing these to be installed anymore. It really grabbed your attention when approaching an intersection.
rdamonThere was an experiment where they were adding white strobe lights to a red signal.
There are places where those are most beneficial. The fact that they're not everywhere enhances their effectiveness.
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