Red tail lights for On30 Trolley

[dtpowell]

I want to add reversing red LED tail lights to my On30 trolley and was wondering if it is possible to add them to the existing circuit? Has anyone added them or has another method to add lighted tail markers?

[SideTracked]

Hi dtpowell,

I'm not sure what existing circuits you have, are you talking about a DC street car or a DCC trolly and trailer? So, I'll do a generic solution:

For DC operation:
Tap into the existing pick-up and temporarily connect the LED.  It should work in one direction only, switch polarity as necessary to synchronize with the motor direction.

For DCC operation:
Bachmann decoders typically use a yellow wire for the back-up (neg) light and the blue for lighting common (pos). (If your chip doesn't have a yellow wire, look at its edge connector for the "R-" marked terminal.) Connect the LED's longer wire (via the resistor) to the blue and the short to the yellow.

Perhaps someone more intimate with your trolley can provide a more specific approach.

Good luck,
Pete

[dtpowell]

Hello Pete,

I'm using the Closed Street Car on straight DC. I'm planning a small double loop free lanced Trolley subway. The single cars will generally operate in one direction only. I will be using Dallee electronics station stops for control. Since the headlight was reversed in direction of travel. I thought it might be easy to add a Red LED to each end. Or, maybe, switch out the headlight for an LED with white/red capability. Your DC operation plan sounds good to me.

Thanks for the information.
Dave

[Jim Banner]

I have not seen red/white LEDs but there are red/yellow ones.  A red or a pair of red LEDs along with a warm white LED would also work well.  Here is a typical circuit:



note that this circuit is for one end only with all 3 LEDs mounted at that end.  A second identical circuit should be used at the other end of the trolley.  Also note that when you turn the trolley around, what were the right wheels for the first circuit are now the left wheels for the second circuit and the left wheels for the first circuit are now the right wheels for the second circuit.

If your trolley company uses only one tail light, then by all means leave out one of the red LEDs.

Jim

[SideTracked]

I'm in the home stretch of a Backwoods Miniatures railcar conversion, and my lighting concerns are similar to yours. I'm using a Bachmann decoder that provides front and rear lighting circuits, but no interior. Similar to Jim's suggestion, I've had to use some diodes to keep the circuits isolated while providing continuous power to the interior fiber optic illuminator.

FYI: There are several types of two-color LEDs. The 3-wire types share a common cathode (or anode). These are available in red/white and can be used for a color changing lamp, but additional circuitry is required. Another type of two-color LED is the bipolar, it has two wires and changes color as your reverse polarity. Unfortunately bipolars don't seem to be available in red/white. Red/green bipolars are great for marker lamps on DC layouts.