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Since this topic comes up all the time, I thought it might be nice to revisit it briefly.  Here's the RailKing Reading Crusader Observation Car that I upgraded to LED lighting and also added passengers.  One of the issues of the observation car is getting decent lighting to the marker lamps and the rear tail lamp.

For the shell, I remove the socket and wiring for the rear bulb, and I slightly extended the wiring for the front bulb and added a connector.  I added the matching connector onto my LED Lighting Regulator Module to make it easy to separate the roof from the car and not have it dangling on a wire.  I added a sprinkling of passengers, including a few standing to add some additional interest.

Here's a quick shot of the finished product.

Reading Crusader Observation Car Lighting N1

Here's the interior of the car before final assembly.  You can see the pigtail from the old light socket with the connector attached.

Reading Crusader Observation Car Lighting N2

This is the front detail of the roof interior,   In the roof section, I stick the lighting module to the ceiling with double-sided foam tape, it's well above the sight line from the windows.  I run the wires over to the LED strip that runs down the center of the car.  You'll also notice I bend the tab on the regulator down so it doesn't show in the window.

Reading Crusader Observation Car Lighting N3

Here's the rear detail of the observation car roof.  This is how the markers and taillight are illuminated.  I take two LED's and form the leads to suspend the LED at the correct position.  They're glued to the roof once the associated wiring is connected.  The taillight LED is simply glued directly to the taillight lens in the roof.  Nice thing about CA adhesive, it dries clear.  You can see the 470 ohm resistor in series with the three LED bulbs, that resistor is selected to provide the desired level of illumination of the lights.  Since each segment of the LED strip has a 150 ohm series resistor and three LED's, these will consume about 1/2 the power of one of the three-LED segments.  The color temperature of the three marker/taillight bulbs is selected to be the same as the LED strip, so any incident light from them just helps illuminate the rear of the car interior.

Reading Crusader Observation Car Lighting N4

In total this car has 18 LED's, and it consumes a total of 25ma of track power.  The side markers and taillight are now nicely lit as opposed to "just being there" as they were with the factory lighting.


Images (4)
  • Reading Crusader Observation Car Lighting N1
  • Reading Crusader Observation Car Lighting N2
  • Reading Crusader Observation Car Lighting N3
  • Reading Crusader Observation Car Lighting N4
Original Post

If you're willing/able to fire up the soldering iron and mess with wiring, here's an alternative for illuminating the two side/rear red marker lights and white center tail light. The idea is to use a "spare" segment of the LED strip which are in blocks of 3 white LEDs.  You probably have a few spare segments lying around.  This means you don't have to scurry around identifying and ordering LEDs and resistors. 

This assumes your observation car has existing red lenses for the markers and a clear lens on the tail light.

buck-boost section separated

Take a segment and separate it into 3 LEDs.  Note that each segment already has the magic current limiting resistor seen on the right of the strip above.

buck-boost lens assembled

Glue the now "individual" LEDs to the existing lenses.

buck-boost led strip connections

The spare segment of 3 LEDs is attached to the end of the main strip that illuminates the car.  The main strip is powered by GRJ's LED lighting module available from forum sponsor Henning's Trains.

buck-boost constant brightness

Ta da!


Images (4)
  • buck-boost led strip connections
  • buck-boost lens assembled
  • buck-boost section separated
  • buck-boost constant brightness

That works well Stan, but the shape of my lenses didn't lend themselves to that technique as readily as the stand-alone version.  I also figured the incident light would help light the rear where the strip didn't extend past the post, a hidden bonus.

Also, since all the wiring is in the roof section, and the markers are on the body, it would have taken extra connectors and wiring to accommodate that scheme.

Last edited by gunrunnerjohn

Here's the next "installment", this is the wiring for the dome car.  Each car presents a slightly different problem.  Since it's a two-level car, you have to deal with multiple strips in order to light it. Since there's a passage way with no windows, I just dropped the lighting regulator into that passageway, job done. You can see the strips are offset going across the bottom of the dome seats, I centered them over the lit portion, I didn't bother to light the passageway that has no windows. The lighting for the dome portion is wired through two small holes at one end, you can see the wires spliced in on the right side of the dome.

Reading Crusader Dome Car Lighting N1

Here's a shot of the completed car from the side all lit up.

Reading Crusader Dome Car Lighting N2

The dome lighting presented a different challenge, there was no overhead beam to hide the lights, and they'd look pretty ugly just stuck to the glass. I fooled around with the idea of a track, but that didn't look good, so I went with Plan-B. I slipped a light strip beside each outside row of seats and did floor level lighting. The effect came out pretty nice, so I'm glad I didn't hack up the look by trying to run them overhead.

Reading Crusader Dome Car Lighting N3


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  • Reading Crusader Dome Car Lighting N1
  • Reading Crusader Dome Car Lighting N2
  • Reading Crusader Dome Car Lighting N3

If you look for it, there are some light strips with remarkably thin LEDs - less than 1mm thick. 


As GRJ says, the wide-angle of dispersion is key for a drumhead or else you'll get a hot-spot (uneven illumination).  Otherwise you have to locate the LED so far back from the drumhead as to be impractical.

Perhaps obvious, but you can carefully remove, say, the last LED from your strip closest to the end of the car.  Then run a pair of fine wires from the vacant pads to the loose LED for the drumhead.  In this way you don't have to find a source for quantity one LED or mess with choosing a resistor.  When purchased on a strip the per-LED cost is usually just a few pennies.


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  • IMG_2841

John, I’ve now upgraded 8 K-line Heavyweights. There are almost as many variations inside as there are cars. I’m up to the Observation car. Before I go any further please take a look at what I found inside this car. Does this mean the drumhead and markers are already lit with LEDs? If so, then I need to figure out where to run the new LED strip.  




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  • 228740A7-C636-43B8-B281-1C34E4B4E09C

As GRJ suggests, the electronics suggests these are NOT LEDs.  For one, LEDs have + and - polarity.  Yet, even though the manufacturer obviously has red and black wiring, they chose to use 2 red wires to the drum lamp, and 2 black wires to each marker lamp.  If you can read the lettering/markings on the circled component, it should tell us the bulb voltage.


Some additional comments if you plan to do an LED conversion.  It appears that your marker lights are in a housing with 3 lenses facing front/rear/sideways...and that they may be multiple lens colors such as the amber/red shown above.  Your photo suggests the bulb is fed into the marker housing through a single hole.

I can't quite tell but it appears that GRJ showed earlier a 3mm diameter LED for a marker.  But if your marker has 3 lenses, you will probably want to modify a 3mm white LED.  An off-the-shelf 3mm LED with the rounded-dome lens projects light in a somewhat narrow-conical beam.  With a small file, emery board, sandpaper or whatever lop-off the rounded dome to make a more flat-top, as well as creating a "frosty" surface which better scatters light sideways.  This will better emulate the wide-angle of an incandescent bulb to illuminate all 3 lenses.

3mm LED modification

I mentioned earlier but did not illustrate another technique when using the LED strips.  You can remove an LED and insert a 2-wire extension cable from the vacated solder-pads to a remote white LED.  Here's a surface-mount LED and a 3mm LED using this technique.  The surface-mount LED was one removed from the strip itself.  Perhaps obvious but note that you can use this extension-cable method for any LED on the strip.  You do have to mind the polarity - red/black wires shown for +/- in photo below.

led strip extension to bare LEDs

Wiring up these tiny LEDs can be a soldering challenge, but you can buy pre-wired LEDs which can reduce some soldering hassle.  The benefit of this technique is you don't have to mess with resistor(s).  And if you are using GRJ's lighting board to drive the LED strip, you get the advantage of constant-brightness, no-flicker, and DCS-compatibility.



Images (3)
  • regulator
  • 3mm LED modification
  • led strip extension to bare LEDs
Last edited by stan2004

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