D&RG ALCO

Graham

In Smoggy Land
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I have acquired a vintage D&RG ALCO which Paul of P&S has converted to DCC. One question I have is the red LED over the cab, it only comes on in reverse is this correct?
 
Yes its a rear end warning light, probably for two ended trains or helpers.

Btw, its a very old tech LED, and a bit dim, relatively speaking.

I replaced it with a modern one, and its so much brighter it atually projects an almost " blinding" focused red beam. As easy as pulling out the old led from its roof top housing, aligining the polarity leads of the LED and you're done. Worth the dollar you'll spend, imho.
 
Yes its a rear end warning light, probably for two ended trains or helpers.

Btw, its a very old tech LED, and a bit dim, relatively speaking.

I replaced it with a modern one, and its so much brighter it atually projects an almost " blinding" focused red beam. As easy as pulling out the old led from its roof top housing, aligining the polarity leads of the LED and you're done. Worth the dollar you'll spend, imho.
Thanks for the info I will give it a go
 
Do you want a bright rear one though when pulling a train as the tail light would then be on a caboose? To be honest a dim light only visible at night is more realistic ;)
The other issue with the light is if flickers so there may be a poor connection that n needs looking at as well
 
The other issue with the light is if flickers so there may be a poor connection that n needs looking at as well

Is this the light that flashes on an analogue loco??

I found the flashing LED did not like the output from the decoder.. A small electrolytic capacitor was enough to smooth the supply to this lamp so that it flashed as it should. - Does only need to be a small one.. On the loco I did, it had enough storage to keep it flashing for a few seconds after power was off.

NOTE:
This is from memory.. It was a while ago, and I am sure it was that way round, and not it was steady on analogue, but flickered on DCC. - In which case, the small electrolytic would cure the flicker..
 
I found the flashing LED did not like the output from the decoder..
Was this a case of trying to drive the LED from a decoder output set to a low voltage by a CV? This is usually achieved using PWM at a reasonably high frequency, but if a large reduction in apparent voltage were needed then maybe the PWM duty cycle was just too short for the electronics in the flashing LED to stabilise. I've never been a fan of using decoder CVs to lower the output voltage, it's something else you have to remember to program if you ever replace or reset the decoder. I always leave the output at full voltage and use a series resistor.
 
Was this a case of trying to drive the LED from a decoder output set to a low voltage by a CV? This is usually achieved using PWM at a reasonably high frequency, but if a large reduction in apparent voltage were needed then maybe the PWM duty cycle was just too short for the electronics in the flashing LED to stabilise. I've never been a fan of using decoder CVs to lower the output voltage, it's something else you have to remember to program if you ever replace or reset the decoder. I always leave the output at full voltage and use a series resistor.

Very probably..
 
Do you want a bright rear one though when pulling a train as the tail light would then be on a caboose? To be honest a dim light only visible at night is more realistic ;)
The light shows forwards Paul, for use when the loco is at the back.
 
Yep I got that bit but often on a double header it ends up facing the lead car so a superbright LED just illuminates that looking rather odd ;)
If it's the tail end pusher in reverse it's realistic but how many trust pushing / banking on their line without easy curves ;)
I just think the stock light is probably more realistic but if they want bright lights then Rule 8 applies ;)
I turn all my lights down to simulate oil lamps or scale bulbs as only the most modern rail headlights illuminate anything ahead, they were all intended as markers rather than actual headlights in the Alcos era.
Nowt wrong if you like seeing the trains lit up just a matter of taste :)
 
Very true Paul - also, if its powered by the decoder it can't be difficult to make it switchable.
 
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Yep I got that bit but often on a double header it ends up facing the lead car so a superbright LED just illuminates that looking rather odd ;)
If it's the tail end pusher in reverse it's realistic but how many trust pushing / banking on their line without easy curves ;)
I just think the stock light is probably more realistic but if they want bright lights then Rule 8 applies ;)
I turn all my lights down to simulate oil lamps or scale bulbs as only the most modern rail headlights illuminate anything ahead, they were all intended as markers rather than actual headlights in the Alcos era.
Nowt wrong if you like seeing the trains lit up just a matter of taste :)

great point

simply, however, when i have seen photos of the 535s, it seems WPY ran elephant style multiple units, so, perhaps, the lighting of a car bulkhead could , by choice, not be a problem.

and, being a bear of little brain, while dim works (especially for me LOL), there is something intriguing, almost spectacular (well not quite) about running the super bright clear, as opposed to older cloudy plastic, red at night, at the rear of the train. it lights up the nearby foliage and is "different". not unlike , imho, the super bright blue white front LEDs on the LGB Genesis locos. I only suggest it because its easy, reversible, cheap, and a small thrill, until one decides otherwise.

FWIW
I would love to re-do the class lights near the front headlights, but, as of yet, cant really think of a simple option, as the lens for the class lights doesn't present an easy re-work.

I would love to have the red ones small directional LEDs, possibly even red/white, and the greens bright and clear.

I like lights, like small children with bright colors or little animals with shiny objects...........
 
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