Installing lighting into Bachmann's Class 25/3 diesel.

I gather that the version I have is no longer available, so maybe Bachmann have updated this loco to a 21 pin decoder and fitted lights, as often happens, but as my example isn't so fitted, here goes with a "How-To". Removing the 4 screws located inward of the inner bogie wheels, it's off with the body for a bit of a 'brainstorming' session, working out the best way forward. I removed the fitted 'Driver' and 'Second Man' at the front end as they're in the way, and felt I could get 2mm dual red/white 'lighthouse' LED's in with a bit of surgery, my idea being that since it wasn't possible to fit LED's to the body, I could fit them to the chassis and get them to shine through the existing clear lamp 'lenses' in the body. First step was to add a small strip of Plastikard across the front of each cab footwell area, as there was only a small area in front of the 'Second Man's' position. Once this was glued in position, I removed the 'lenses' in one end of the loco body and slipped it back on.

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Slipping the body back on, I then drilled a 1mm hole, using a pin vice, through each 'lens' hole and also through the footwell 'bulkhead, part of which I had just fabricated.

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Once one end is done, swap the body round the other way on the chassis, and repeat the drilling procedure as before. When you have the 4 holes in position, remove the body, and using a 2mm drill in the pin vice, open out the holes in the 'bulkhead (NOT the body!) ready for the tubular section of the 'Lighthouse' LED's to fit into, thus holding each LED directly in line with each 'Lens', and shine through.

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Now it's time to prepare the 4 LED's for fitting. It's necessary to cut down the leads from each LED to about 10mm maximum as these wires aren't very flexible and they need to be to get them in the positions I need. Don't cut the LED leads shorter than the 'crimps' about 5mm from each LED body! I've used blue wire for the common +ve (centre) lead (on dual LED's), white for the white LED, red for the red, which keeps it simple and easy to remember, even for me! Heat shrink each connection, leaving each wire about 150mm (6" in old money!) for connecting to the decoder.

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We don't need the light output from the main body of each LED, in fact it would be a nuisance, so at this stage, black PVC tape or paint each LED body, but NOT the tubular part. Our intention is for the light to be concentrated down the tubular 'lighthouse' part of each LED, so it shines directly onto each 'lens' in the body. These are now ready to fit.

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Now to fit these LED's into the chassis. Basically, the tubular part of each LED is just pushed through the hole in the 'bulkhead' as far as it will go, wiring being slipped between the back of the cab moulding and the weight/motor housing behind, leading the wires over ready to connect to the decoder. Glue each LED into position ensuring the tubular part is as far forward as it will go.

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This closeup shows things a bit better.

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Once the glue has set, it's a good idea to black paint any areas where there is any light 'leakage, as we want all the light to go 'down the tube' so to speak! I just connect a 9volt battery to each LED in turn (DON"T forget to use a 1kohm resistor in the +ve lead, or "POP" goes the LED!!!) so it's easy to see any light leakage. After this, I've used black heat shrink on the protruding tubular 'lighthouse' part of each LED, once again to concentrate the light output and prevent stray light from illuminating the cab where we don't need. What we need is something like this below.

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I may need to slightly trim back the heat shrink on the tubular part of the LED's if the body won't quite clear the ends of the shrink, but that's not a problem. At this stage, I'm awaiting delivery of the decoder, so can't do final connecting and testing, but next I'll look at cab lighting for this Class 25. The pic below shows what I've tried to achieve, concentrating the LED light output down the tube so it shines onto the back of each 'lens' in the body.
To be continued.

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Well, decoder arrived today, so I've now been able to complete the job. As Bachmann have done a good job with the pickups on this loco, I won't need to bother with using the 'stay-alive' connections on the decoder. These "Lais" decoders are quite good value for money, worth a look if you've got a good few loco's to fit DCC decoders into. 4 functions and stay alive, fully sleeved so no heat shrink to fit and (just!) under a tenner apiece in the UK. I've no connection with either seller on Ebay (One in Derby, the other in East Anglia), just find these a good, cheap decoder for 00 gauge.

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The decoder is quite small, so no difficulty in finding space for it. I added a cab light at each end, and as the roof fan is close to the cab rear moulding at one end, instead of fitting the LED to the cab roof, I just bent a small piece of Plastikard at right angles and stuck an SMD LED onto it, then glued the Plastikard onto the rear of the cab moulding so the LED was over the cab area, but unseen. As these LED's were quite 'white', I gave each a coat of "Warning panel yellow" to make them more like incandescent lights of the period. Connecting all the lighting up is quite simple, all the blue (+ve) wires with 1k resistor in series, goes to the blue on the decoder, front white/rear red wires to decoder white, rear white/front red wires to yellow, front cab light to green, rear cab light to purple, heat shrink all the joints as you go, then time for setup and testing. With decoder set up, front lights on but cab lights off below.

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This time, front lights with cab lights as below.

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I did try to take a pic with red lights lit, but my phone camera just would not show these up very well! Suffice to say, I'm quite happy with the results of my efforts, and this sort of approach to 'extra' LED fitting is fairly easy on many diesel models if you think carefully before starting, and make sure your chosen LED's will actually physically fit before any surgery. I have to admit that soldering SMD LED's is not easy due to the (very!) small size of some types, I find it easier if you first stick the LED onto a bit of double-sided tape, much better than chasing it around your bench top with the soldering iron, and since there are no fitted wires onto this type (though I gather you CAN buy pre-wired ones), you do need to test which is the +ve end first. I have a PP3 battery with a couple of wires on, (plus the 1k resistor on the +ve wire) and use this to check which connection is the +ve (via resistor) connection. Other than that, there's nothing too difficult, if you can solder effectively and aren't afraid to take a model apart, you really won't have much problem in adding lighting details to your models.
Keith.