New lighting strip for REE unified railcar trailer

Original page created on 06/09/2023 ; last modified on 15/10/2023.

REE unified railcar trailer, profile view

REE unified railcar trailer, profile view (before modification).

Observation

A few of us found the lighting solution adopted by REE for its unified trailer, which is otherwise very successful, bizarre. Not possible to swap the tail lamps, no lighting control. A specific PCB for the DCC has been announced, but when and at what price? Also, this very narrow strip and its support are completely warped, at least on my trailer.

As I had designed a strip for Roco trailers, I decided to adapt it to the REE model.

First tests with a Roco trailer strip

I started by dismantling the body, with no particular difficulty, then the interior fittings (four clips on each side), then I discovered the wiring: all grey and black wires! Where I would have liked to see red and black for the track, and blue, white and yellow for the lights, all I saw was grey! Sad! And not easy to spot!

Trailer, dismantled layout

Roll over the image with your mouse to see the details.

The wires in the 4-pole connector (the one for the lanterns) are too short to be reused. So, instead of cutting these wires and extending them, I’m going to rewire the whole thing using standard colours:

To connect them to the new wires, the lamp circuits are easily removed from the chassis.

Here’s the new look once the interior is back in place.

Trailer’s chassis rewired

Here’s how it looks with the Roco trailer strip. A little adaptation was enough for conclusive tests. There are two 330 µF capacitors wired in parallel. Note that I had to remove their sheaths to be able to insert them between the walls (the gain is about 0.5 mm).

Wiring the strip, to the front

There’s a slight improvement in terms of maintaining lighting when the power supply is cut, to the order of one second. Better than nothing, and certainly better than with the original REE strip.

New strip

Once these tests had been validated, I made a new strip specifically for the REE trailer, in particular for the fixing, but Roco compatible (hence the multiple notches visible on the edges).

Here are some strips with the 21MTC connector soldered on. I first tried hot-air soldering, but I was a bit surprised: the connector moved as if on ice!

Finally, with a very thin, pointed tip, soldering with an iron works very well: start by soldering two diagonally opposite tabs. Once the connector is fixed in this way, make the other solder joints.

New strip with its MTC21 connector

Click on the image to zoom in.

Note the keying position indicated by the cut pin (no. 11), shown on the silk-screen print.

Fitting the strip

On the fastening side, which is the original one, I inserted a 1 mm thick washer (arrow) to even out the height of the circuit. You can of course use plastic card of the same thickness.

Fixing the strip on the van side

Click on the image to zoom in.

On the toilet side, you can see the capacitors “surface mounted”, with a simple 90° bend of their wires. Their pads were designed for through-hole mounting, but in the end it's much simpler this way. The capacitor on the left needs to be flush with the underside of the board, so the bend height of its wires needs to be about 1 mm. This way, it passes over the interior fittings.

Placement of capacitors in toilets

Click on the image to zoom in.

Connection

From their exit from under the fittings, the wires pass behind the capacitors, then into the hole in the PCB provided for this purpose. There’s no longer any need to apply Blu-Tack, as I did when I first tried this out.

It may be that the capacitor on the left, placed higher up to pass over the fittings, is preventing the body from being put back into place, because of a conflict with the part representing the curtains (see arrows). Personally, I solved this problem by cutting this part at toilet level: it doesn’t detract from its holding, and it’s perfectly invisible.

Cutting out the curtains

Another solution would be to cut out the part of the fittings that held a fixing screw for the original strip. This would allow the capacitor to be placed lower down. However, this would involve more work and, in my opinion, would detract more visibly from the original appearance.

Note that the absence of a fixing on this end is not a problem: the capacitors, which are well fitted in the toilet, do the job very well. The strip is horizontal, which was not the case with the original…

Decoder

The decoder outputs are wired as follows:

Here’s a view of the fitted decoder (ESU Lokpilot 5 FX in my case). Caution: a longer decoder could hide the van lighting LED, visible at the end of the strip.

View of the decoder under the strip

Click on the image to zoom in.

Conclusion

The only drawback, to my eyes, is that the connector can be seen from the side… But would it be possible to install a Next18, which takes up less height, above the circuit? I’m not sure, because there’s not much room under the roof. In any case, I wouldn’t be able to solder such a connector.

Trailer profile view

Good luck to my friends on the forum who are going to wire these strips!