Title says it all. On relay cabins next to the tracks at crossings and other places, there is a bright white light behind a lens, aiming down the track. From the East Lansing station platform, I can easily see the light near a crossing a half mile away.
What is the purpose of these lights? I have never seen them go off, blink, or otherwise change. Not all cabins have them. I assume it conveys SOME sort of information, presumably to the train crew, but what?
In most cases, it is displaying that Commercial Electrical Power is reaching the Relay box. If the light it is out is is indicative that Commercial Power is out and the Relay box is doing its functions on battery power. Battery power is finite and won’t last forever. The absence of the light tells the signal maintainer that he needs to either contact the power company to figure out when service will be restored or start hunting for a electrical generator to supply power to the Relay box so it can continue to function.
Presuming that the area is operating on CTC - the Train Dispatchers model board will also have a indication that Commercial Power has failed at a location. If the Power Out indication persists for more than a few minutes - the Signal Maintainer will be notified to investigate.
Just a brief note: Recently, I’ve noted that the lights on the relay cabins, along the BNSF in this area seem to have taken a much brighter glow.
Seems like they are replacing older incandescent bulbs, with much brighter halogen bulbs, or LED bulbs? Same on the exterior lighting on locomotives? Is it just that they are ‘better’, or is there some ‘regulation’ driving this change?
Ours have gotten brighter in recent years too.
On CN the light has the following meanings:
On: Everything is normal.
Flashing: Crossing is running on battery power.
Extinguished: No power of any kind. The crossing will most likely not work in this situation.
Crews encountering a flashing or extinguished light are to report it to the Dispatcher, who will notify a maintainer. Trainmasters can deliberately make the light flash as an “efficiency test”, I believe without disconnecting the crossing from main power.
The relay boxes at our crossings, in addition to a light showing everything is active and working, have a commercial power out strobe light. We are to turn in to the dispatcher when the strobe light has been activated.
Jeff
Before our boxes started receiving the separate strobe light, the efficiency test was to cover the light. Normally done during night time hours.
The older boxes had a small light, recessed into the box. Easier to cover with some duct tape. Newer ones are larger and protrude a bit. One crossing box has one that looks purple from a distance, then a bluish white color when passing it.
Jeff
The bluish LEDs appear brighter, no doubt because the color is purer than an old fashioned incandescent.
I have LED DRLs on my truck. If you were to judge which was brighter, you’d say the LEDs, but if I turn off the incandescent headlights at night, I can barely see 100 feet.
I haven’t heard anything about LEDs being required, but considering that they draw a fraction of the power of an incandescent, they cost less to operate - a prime consideration. That’s even a consideration on a locomotive, where they are simply a parasitic load. Better that power go to the wheels.
My light bill is much less than it was before I started replacing incandescents with LEDs.
“White” LEDs emit light in the wavelengths that we refer to generally as being Red, Green and Blue. But, they are very narrow bands of those colors. They do not emit other colors, such as Yellow, or wavelengths that we might call Red (or Green or Blue) that are just near the wavelengths the LED does emit.
When you look directly at an LED, your eye responds to the signal strength of the 3 colors it is emitting and you perceive a very bright White light.
Your eye responds to very broad bands of Red, Green and Blue wavelengths, not just the narrow bands that LEDs emit.
Objects, on the other hand, reflect some wavelengths more than others, including wavelengths that an LED does not emit.
When LED light is projected onto objects, if the wavelengths the object reflects are not one of those narrow bands that the LED is emitting, then there are no wavelengths to reflect. Thus, your eye will perceive the object as dark (in the total absence of other light and if the object does not reflect any of the narrow bands available, then it will appear as Black).
I think it is funny in that advertisement on TV, where they claim a flashlight can be seen over 2 miles away and so it must be wonderful to use to light your path. It IS good for signaling if you are signaling someone that has direct line-of-sight to the flashlight, but you still cannot read a newspaper with nothing but that flashlight as the source of light. White newsprint paper may not reflect much of the particular wavelengths the LED is emitting and thus appear very dark against the black ink.
In my experience, using LEDs as headlights on cars is not a good idea… to get enough light to make the driver feel like he can see the road, you blind oncoming drivers that are in direct line of sight to the LEDs.
LEDs are improving. Today the wavelengths they emit are broader than they used to be, but they are still not good
A problem we’ve had with the LED headlights on our new pumper is RF interference on the fire band. We’re going UHF this fall, which may render this a non-issue, but it’s still a factor now…
I am wondering how LED’s affect those that are color blind?
I recently replaced the fluorescent lights in my shop with LED’s, and now I can’t listen to my favorite FM station which happens to be very weak in this area.
Going back to headlights–I’ve been concerned since halogen lights about the switch to the bluer color. They appear to be brighter, but the yellower wavelengths are better at penetrating fog or haze. I seem to be the only one in the world concerned about this.
And the flicker the LED’s produce drives me to migraines. I used to think the flicker from fluorescents was bad, but the LED’s really strobe.
I had hung a string of white LED xmas lights down one of my stairways, thinking they would be a thrifty night light. But both my wife and I instantly were bothered by dizziness when using the stairs–not a good place for being dizzy. Once the LED’s were removed, the headaches and dizziness went away.