M636CThere is nothing in the regulations that suggest the type of technology to be used. However, I'm not sure how you would dim an LED headlight - possibly just use a secondary light of lower power.
The secondary diode core(s) approach will certainly work,, and it has the secondary advantage that the 'dim' can be at a different reflector focus and/or aimed downward to carry well but provide less 'dazzle' to oncoming crews. It also ought to be compatible with existing switch arrangements.
However, I think it's probably at least as good to dim by modulating the voltage to the diodes at very high frequency, similar to the way older triac dimmers worked. The net result is not only that fewer lumens are emitted at the diode in operation, but that the diode is not powered a considerable portion of the time, so the 'net' illumination is less.
BaltACD FRA Locomotive lighting regulations https://www.law.cornell.edu/cfr/text/49/229.125
FRA Locomotive lighting regulations
https://www.law.cornell.edu/cfr/text/49/229.125
There is nothing in the regulations that suggest the type of technology to be used. However, I'm not sure how you would dim an LED headlight - possibly just use a secondary light of lower power.
What did strike me was the regulations say nothing about how the headlight performs as a light for the operator. They are only concerned with how the light appears to those outside the train.
In Australia, the ditch lights flash automatically when the horn is sounded.
The recent Chinese SDA-1 type locomotives in Australia also flash the ditch lights when they are powered up and when the brakes are released, handy for employees in yards and depots. They have LED ditch lights but incandescent headlights.
M636C
M636CThe blue white headlights show up more clearly at greater distances, but I can't say what the view from the cab is like at night.
I put LED DRLs on my truck. They're bright to look at, but you wouldn't want to drive with them at night.
OTOH, the LED headlights on our new fire pumper are plenty bright for driving, and aren't as blue as many of the LEDs you see. Given the proper optics, I suspect they'd be just fine on a locomotive. I have seen step lights, etc.
We're starting to replace some of the light bulbs in our passenger cars with LEDs. There aren't enough yet to make a major difference in HEP load, but time will change that.
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...
Never too old to have a happy childhood!
In Australia, Pacific National, one of the two biggest operators has refitted their main intermodal units (120 units altogether) with full LED lighting at their 15 year overhauls.
This includes headlights, marker lights and flashing ditch lights.
The blue white headlights show up more clearly at greater distances, but I can't say what the view from the cab is like at night.
The LEDs are fitted into standard casings and are the same size as the sealed beams they replace. They are a dense matrix of hexagonal shape with maybe 50-100 individual LEDs. Two are fitted, like sealed beams.
The ditch lights consist of six larger LED units each arranged in a circle, again, fitted in the usual incandescent lamp casings.
Marker lights are similar to the headlights but smaller, and come in red and white, of course.
Many locomotives have been built with, or have had LED marker lamps fitted at overhaul.
The preserved Beyer-Garratt 6029 has LED headlights and ditch lights. The ditch lights, not being original, are quite small to reduce the impact in appearance, particularly when out od use. Since the locomotive is overall glossy black, the lights are important visual aids.
The Sydney "Waratah" trains (78 eight car sets) have full LED lighting inside and out. However, the power required for propulsion and air conditioning mean that there is little net power reduction. The long life of the LEDs is a cost reduction, maily in manpower to replace bulbs and tubes.
I also wonder if itwill. Used in newer passenger cars. That could be a substantial reduction in HEP needed.
Modeling the Pennsylvania Railroad in N Scale.
www.prr-nscale.blogspot.com
zugmann Amtrak uses led headlights/ditchlights in their new electrics.
Amtrak uses led headlights/ditchlights in their new electrics.
Some of the newer diesels seem to be using LED lighting on steps, and some of the 'other' lighting around the sides (manway(?) areas of newer locomotives.
Also have not noticed any of LED style on the headlamps or ditch lights.
The city of LaGrange Ga is replacing mercury vapor & metal halide street lights with LEDs. The LEDs are very aimable and tend to place much more light on the street. we notice that the lights across street ( either way ) are pointed more toward us but once in the opposing lane for left turns they are very much brighter, The aiming certainly may be important. No one has indicated how the city is disposing the now surplus fixtures and to a lesser extent bulbs that still have life ? l
BaltACD A drawback of LED's is they don't generate enough heat to melt snow and would need constant cleaning when used in such conditions.
A drawback of LED's is they don't generate enough heat to melt snow and would need constant cleaning when used in such conditions.
IIRC, some automotive LED fixtures actually include heaters for that very reason.
GP-9_Man11786Is it [conceivable] that locomotives could head on the same direction once the LEDs become cheap enough?
I had thought the move toward LED lighting was well advanced, both in 'new build' locomotives (the ACS-64s for an immediate example have them) and in the retrofit market.
There are advantages other than first cost, and I suspect the reduction in maintenance cost is better than 'minuscule' especially including the reduction in cost to remediate a conventional headlight that has gone out 'on the road' and has to be replaced under applicable rules.
It has probably taken some time for the 'cheaper' LEDs and support circuitry to make it into the 64 to 72V, heavier-shock railroad world effectively. Remember that historical issues with LED high-power lighting involve the considerable heat-sink requirements and the inherent low resistance to voltage spikes -- but once solutions to these have been costed down, or a price and reliability point reached which outperforms traditional (and often costed-down) solutions -- expect to see it across the board.
One interesting issue with LED main lighting is that some of it is multiplexed, meaning that one 'driver' circuit works for many physical light-emitting diodes with some persistence-of-vision and internal phosphors making up the difference in continuous light. This shows up dramatically in digital photography of some of the units equipped with these lights. Digital photography can have extremely fast effective shutter speed (with the additional 'exposure time' involving post-processing and storage of the captured image) and it's not uncommon to see pictures in which multiplexed lit LEDs have not registered as 'on.' I have been waiting with some amusement to see these sent to railroads as evidence of 'rules violation' or brought up in court by ambitious attorneys eager to show railroad 'negligence'. There are probably some people who would believe the evidence of their lying eyes and not want to hear the "excuses"...
One other advantage of cheap LED lighting is that it can be applied in places other than 'traditional' light housings or positions. Combined with a certain amount of active or steered focus, it may be possible to provide a large amount of "visual stimulus" in addition to just head and ditch lights, or actively provide high-intensity projection or images in the 'skin' of the locomotive; some of the interesting possibilities seen in LED 'building lighting' and graphics have definite application in railroading.
It's been fun. But it isn't much fun anymore. Signing off for now.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.t fun any
a lot of automobiles have switched to using LED clusters for head and taillights. Is it concievavbly that locomotives could head on the same direction once the LEDs become cheap enough? The only real advantage cpuld be a minuscule reduction in maintenance and brighter head, marker ditch lights.
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