# Are porch lights direction sensitive?



## JackM (Jul 29, 2008)

I'm not sure this question belongs here or in the operations forum; I can't find the information I need in either one.

My winter project is a new GP-40 for the railroad and I'm now in the process of upgrading from incandescent lights to LEDs. I barely had time to make sure the engine was at least self-propelled before the first snow, so I didn't pay much attention to lights til now. My question refers to the tiny PC board which holds the two red marker lights and the white porch light on the FRONT hood.

I've changed out the old bulbs for LEDs and I'm now attempting to test my connections with the bench power supply, just putting 9vDC to this board.

1 - Am I correct that the red markers are full brightness going forward, and dimmed when backing up? As I recall that's what I have with my RDC-1.
2 - Are the porch lights on all the time, or only when going backward (as indicated by the dimming of the red markers)? Porch light is on only when the red markers are dim.

I'm going by George Shreyer's schematic in his RDC page. I think I have it right but I would expect the porch lights to be on all the time. If so, I think I know where I went wrong. Of course, the GP is spread out in a million pieces all around the basement so I can't exactly give it a real life test now. (I'll be using the QSI plug 'n play board.)

JackM


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## rdamurphy (Jan 3, 2008)

The "markers" on the front hood? With the red lenses? On some railroads, at one time, whenever a locomotive was stopped, the headlight would be turned out, and those red lights turned on. They were kind of like "parking lights." D&RGW and others used the ones on the hood, the SP used on in the "light clusters" up on top of the cab and on the end of the long hood. If the locomotive was at the back of the train, used as a helper, they would be used to mark the rear of the train, sort of like the way a FRED is used now. 

The porch lights were for safety, and would be on at all times, even while stopped or parked. In fact, step lights on the lead locomotive will deadline the train if they're out. 

Hope that helps! 

Robert


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## JackM (Jul 29, 2008)

Maybe I'm using the wrong term. Not the red markers. 

Both ends on my GP-40 have a pair of clear plastic horizontal lenses at the bottom of the "point" of the hood, they (each end) are lit by a single bulb. They seem like their purpose would be to light the walkway at each end of the engine. If I have that right, you answered my question - they should be on at all times. 

That helps! 

JackM


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