# What light did I see on the front of a train?



## BatteryCharger (Jul 29, 2004)

I was camping recently in the middle of nowhere in the desert. A train came by at about 1:00...with a light that lit up EVERYTHING. It made my 2 milion CP spotlight look like a stock mini mag. What kind of light was that? I want one! /ubbthreads/images/graemlins/grin.gif


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## jtr1962 (Jul 29, 2004)

Here is some information on locomotive lighting. Specifically, we have:

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The FRA requires that the locomotive headlight (steady burn) used for road service have a luminous intensity of at least *200,000 candela*. The headlight light focus angle in the horizontal plane in relation to the centerline of the locomotive must illuminate the track so that the locomotive engineer can identify moving or stationary objects or conditions at a distance of 244 m (800 ft) in front and ahead of the locomotive. The reduced luminous intensity (60,000 candela) and distance requirements (91.5 m [300 ft]) for railroad yard headlight operation is required to reduce excessive glare for railroad employees.


[/ QUOTE ]

and

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Typical steady burn locomotive headlights are defined by wattage, style of headlamp, and voltage available. Locomotive headlight wattage was determined to range between *200 and 350 watts*.


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Short answer-locomotive headlights are blindingly bright and visible for miles. I used to watch trains at Princeton Junction on the Northeast Corridor when I was in college. In the _daytime_ you would see the headlights of the AEM-7 locomotives about 2 or 3 minutes before they passed through. At the 125 mph speed they were traveling, this translates to a distance of four to six miles out. At night they probably could be seen from ten miles out or more if you had a straight line of sight.


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## yuandrew (Jul 29, 2004)

The light you see at the end of the tunnel is the headlight of a fast approaching train 







Ok, It says it is a PAR 56 lamp running at 200watts and 30 volts DC. Made by GE.


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## BatteryCharger (Jul 29, 2004)

How could a 200 watt light possibly make 200,000 candela? (is that the same as candle power?) My spot light is 100 watts and it made it look like nothing....


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## jtr1962 (Jul 29, 2004)

It's a very narrow beam (about 4°). 200,000 candela (1 candela=1 candlepower) average intensity over 4° equals about 800 lumens. Probably when you account for the inefficiency of focusing at such a narrow angle you might need closer to 2,000 or 3,000 lumens. A 200W light can easily deliver this. In fact, that report I linked to shows the 200W headlights putting out well over 200,000 candela. LED manufacturers use the same trick. A 10 candela LED with a 20° beam angle only puts out about 1 lumen (actually about 25% more counting what's outside the main beam). It looks very bright. However, if the same light were spread out over 180° (i.e. a hemisphere), the intensity would only be about 0.2 candela-not conspicuous at all.


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## BatteryCharger (Jul 29, 2004)

So that little bulb pictured above puts out ALL that light? Do they only use one of them? I was quite confused for a few minutes, it really looked like the sun was coming up over a hill. (although I was a bit intoxicated at the time /ubbthreads/images/graemlins/grin.gif )

So where can I buy one of those? /ubbthreads/images/graemlins/smirk.gif


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## jtr1962 (Jul 29, 2004)

Actually, one for the headlight and two for the ditchlights. They generally use the same bulb for all three. Small wonder it looked like the sun coming over the hill with 600 watts of focused light. /ubbthreads/images/graemlins/smile.gif


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## yuandrew (Jul 30, 2004)

Guess you'll have to look around on GE lighting yourself to find something identical; if not similar to the sealed beam above. It will probably be under speciality lighting 

Good luck rigging up a 30 volt power supply/ battery pack and a heat resistant holder/handle for it!


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## smokinbasser (Jul 30, 2004)

I was camping once and we had set up after dark and I was awakened by the train horns and my jungle hammock(read zipped in for bug prevention) and my entire area was bathed in light and I tried to remember if I might have tied the hammock between two poles straddling the tracks,thankfully not but REAL close.


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## BatteryCharger (Jul 31, 2004)

Well, after seeing a few threads about aircraft landing lights in the spotlight section, and searching ebay, I can see that these PAR 56 bulbs are also used in airplanes. I'm going to get a 600 watt version. /ubbthreads/images/graemlins/grin.gif


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## Hoghead (Aug 13, 2004)

There are 2 headlights that are 200 watts each and there are 2 ditch lights that are 350 watts each. The headlights are the ones in the middle (usually quite high on the engine and right next to each other) and the ditch lights are always lower and spaced a few feet apart. 

Visibility was much improved with the addition of the ditch lights a few years ago. 

If you put a headlight in where a ditch light is supposed to go the headlight will flash in a heartbeat. It will flash so fast that you will think you had a defective bulb /ubbthreads/images/graemlins/hahaha.gif /ubbthreads/images/graemlins/blush.gif

They are the same size and the only way to tell them apart is to read on the back of the lamp if it's 200 watts or 350 watts. The box they come in or the back of the lamp might tell volts or amps, but I don't remember.


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