I have a guy I went to school with and he is a railroad consultant for Amtrak. We had a discussion about the wayside signals presently and although what we talked about is different than the results of this question on the color of signals changing, he mentioned that now many roads and basically CSX will have an active rail section with wayside signals and they will show "dark" like not working which is to save on power to the signals (recharge batteries). Then when the train is entering the signal block, the signal will illuminate with red aspects and then will switch to the correct signal aspect color for that block as the train approaches the signal. The short period of time for it to display red aspects is so the engineer knows it is working properly. Originally many years ago I saw the wayside signal that was near a station in Newark NJ and that signal was also dark, but as the train entered the block it illuminated with the aspect color for the condition of the block. I think the brief lighting of the red aspects first also maybe could be a fail safe in the event the actual block status signal aspect colors are not working the red aspect color may stay and then the engineer would stop on the red signal. If the signal remained dark when the train approaches without this momentary display of red, would be taken by the engineer as a stop and stay. I am not a professional railroader just a model railroader and rail fan.
A color light (or position light) signal which is dark is assumed to be displaying the most restrictive aspect that signal would normally display. Likewise, a semaphore which lost power would display a horizontal blade. This was also true of mechanical semaphores if the linkage became disconnected.
An approach lighted signal which displayed red before cycling to its appropriate color might have a fail-safe 'illuminated - red' if the lamp power is on but the detector circuit is dead.
In this day and age any dark signal will cause an immediate radio call to the DS.
Chuck (Modeling Central Japan in September, 1964 - traffic too dense for approach-lighted signals)
I have never observed the momentary red indication, I would have to think it would just be milliseconds and In my opinion unnecessary. If the signal just lit with the proper indication it would be just as effective. If I'm an engineer and I see the next signal is red, I'm going for the brakes.
Dave H. Painted side goes up. My website : wnbranch.com
dehusman I have never observed the momentary red indication, I would have to think it would just be milliseconds and In my opinion unnecessary. If the signal just lit with the proper indication it would be just as effective. If I'm an engineer and I see the next signal is red, I'm going for the brakes.
Larry
Conductor.
Summerset Ry.
"Stay Alert, Don't get hurt Safety First!"
I have seen 'searchlight' signals 'pump' from red to green as they are approach lit. I suspect that this has something to do with the small rotating vane inside the signal spinning to the correct aspect when the signal is energized. I have heard this happening on color light type signals, but do not remember seeing it happen.
Normally approach lit signals will light up as the train enters the block preceding the signal, this can be a good two mile in front of the train, so the chances of the train crew seeing the signal 'pump' over usually are nil. I remember riding in a dome car about 5 cars back in a train and the signals were just changing from green to red about 1-2 cars ahead of the dome car I was riding in.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
All of our signals that are approach lit are color light types. The ones that you can see come to life display the aspect allowed by the system, no momentary red before changing. Unless red is the best it can display.
We have a few searchlight type signals, but I don't think those are approach lit. I have seen a momentary flash of red as a yellow (approach) changes to green (clear). The red color on the vane is in the center and the change from yellow to green (or vice versa) momentarily places it in front of the bulb. Sometimes there have been cases where when changing the vane "sticks" on the red aspect. We had one absolute (since replaced by a color light signal) that did this. One night we were coming up to a green over red (clear) at the east end of a siding. The track twists around so you can't see the signal at the other end of the siding until you are about a 1/2 mile from it. About that time we heard the hot box detector about 4 miles ahead announce a train over it. We came around the curve and saw the next signal red. We were able to stop short. We contacted the dispatcher and about that time the signal cleared up. It turned out that we were following the train we heard clear that next detector. (We kind of figured that out when there wasn't a headlight staring us in the face when we saw the red signal.)
The signal had just stuck at red when changing from yellow to green. This signal had been known to do this before, but hearing that detector earlier made for an anxious moment for a second or two.
Jeff