rynd2it Posted August 31, 2020 Share Posted August 31, 2020 I'm willing to bet there is a simple answer to this but I can't find it. I have a loco (actually a GWR railbus) which will go in either direction and I wish to add lights to both ends such that when going forward to front lights are white and the rear red. When in reverse the lights should change accordingly but how? Thanks David Link to post Share on other sites More sharing options...
JST Posted August 31, 2020 Share Posted August 31, 2020 This is a bit long and basic but about half way through it tells you all you need to know. Cheers John Link to post Share on other sites More sharing options...
rynd2it Posted August 31, 2020 Author Share Posted August 31, 2020 Thanks for that but it uses separate LED for red and white. The railcar seems to have only one lamp (or pair of lamps) each end which glows alternately red or white depending on direction of travel. In 12" to 1 foot gauge this is probably a dual filament bulb but the only bi-colour LED I can find is a 2mm one which may prove to be too large. Anyone done this on regular diesel loco for example? Link to post Share on other sites More sharing options...
RAF96 Posted August 31, 2020 Share Posted August 31, 2020 (edited) You need a red/white 3-legged common Anode led. The smallest I have seen is 1.8 mm but you can sit it back to shine through a smaller hole in the body, with a drop of PVA glue as the lens. The common anode (middle) legs connect to the decoder blue positive each one via a resistor - 1K ohm will do and the front white and rear red legs are joined together to operate from the white wire. The rear white and front white are joined to operate from the yellow wire. F0 switches on the lights and the direction dictates which colours show. Older DMUs used a Yellow/Red combo, which you can also get in 3-legged form. Common cathode leds are more readily available but of no use in a DCC fit as you need the positive on the middle leg. Edited August 31, 2020 by RAF96 1 Link to post Share on other sites More sharing options...
RMweb Premium melmerby Posted August 31, 2020 RMweb Premium Share Posted August 31, 2020 (edited) The real GWR Railcar generally used 3 lights, a pair of white lights either side inline with the buffers and a central red light as modelled in the Dapol DRC You don't need dual colour LEDs The actual position varied depending which series railcar and they sometimes carried a normal oil lamp on a bracket. e.g. Edited August 31, 2020 by melmerby Link to post Share on other sites More sharing options...
rynd2it Posted August 31, 2020 Author Share Posted August 31, 2020 8 minutes ago, melmerby said: The real GWR Railcar had 3 lights, a pair of white lights either side inline with the buffers and a central red light as modelled in the Dapol DRC You don't need dual colour LEDs The actual position varied depending which series railcar and they sometimes carried a normal oil lamp on a bracket. e.g. You may well be right, problem is that I can't find an image of the rear of one any where. The Hornby one has one end with the lower lamps painted red. Confusing Link to post Share on other sites More sharing options...
trevora Posted August 31, 2020 Share Posted August 31, 2020 24 minutes ago, rynd2it said: only bi-colour LED I can find is a 2mm one which may prove to be too large. You can get these DT0605RW 20pc Pre-soldered litz wired leads Bi-color RED/WHITE SMD Led 0605 DUAL about 1 to 2 mm square 1 Link to post Share on other sites More sharing options...
Nigelcliffe Posted August 31, 2020 Share Posted August 31, 2020 An alternative approach is to use fibre-optics. The fibre/filament is readily available in a variety of diameters. With those, you can put LEDs along side them (touching, putting a small flat on the fibre helps), or at the inboard end. Mask them by glue (eg. araldite) around the finished assembly, then paint the outside to stop light leakage where not wanted. This gives a choice of colour down the same optic. I used that many years ago fitting lights to some 2mm scale diesels. - Nigel 1 Link to post Share on other sites More sharing options...
rynd2it Posted August 31, 2020 Author Share Posted August 31, 2020 On closer examination, the Hornby version has the lower lights painted silver on both ends, a red light in the middle just below the windscreen and another just above the windscreen not painted. The Lima version is similar but no paint on any of the lights. Now to find out how the GWR actually used them. Link to post Share on other sites More sharing options...
RMweb Premium melmerby Posted August 31, 2020 RMweb Premium Share Posted August 31, 2020 1 hour ago, rynd2it said: You may well be right, problem is that I can't find an image of the rear of one any where. The Hornby one has one end with the lower lamps painted red. Confusing There isn't a "rear", both ends are the same. There is an A end & a "B" end because the internal layout isn't symmetrical but the cab ends with the lights are the same. Link to post Share on other sites More sharing options...
rynd2it Posted August 31, 2020 Author Share Posted August 31, 2020 22 minutes ago, melmerby said: There isn't a "rear", both ends are the same. There is an A end & a "B" end because the internal layout isn't symmetrical but the cab ends with the lights are the same. Yes, as I said above. But how were they used? Link to post Share on other sites More sharing options...
RMweb Premium melmerby Posted August 31, 2020 RMweb Premium Share Posted August 31, 2020 (edited) The white lights always show to the front, a red light to the rear in direction the unit is travelling (either way) As to DCC wiring The white lights one end and the red light the other are connect to the first decoder function output (white wire) the alternate pair are connected to the next function output ( yellow wire) - which are the default front and rear lighting outputs on a decoder. Blue is common positive That way you only have two states to consider and the decoder does it automatically. (F0 switches them on/off) Edited August 31, 2020 by melmerby Link to post Share on other sites More sharing options...
rynd2it Posted August 31, 2020 Author Share Posted August 31, 2020 15 minutes ago, melmerby said: The white lights always show to the front, a red light to the rear in direction the unit is travelling (either way) Yes, I know that but which of the middle lights are used to indicate red, the lower one by the logo or the one above the windscreen? Link to post Share on other sites More sharing options...
RMweb Premium melmerby Posted August 31, 2020 RMweb Premium Share Posted August 31, 2020 4 hours ago, rynd2it said: Yes, I know that but which of the middle lights are used to indicate red, the lower one by the logo or the one above the windscreen? The one by the logo is red, AFAIK all others are white. The white lights approximate to normal loco headlights although the DRCs are usually depicted with the outer pair lit (express passenger). (I suppose some workings could be considered stopping trains and may need a different lamp arrangement alight) Which period are you depicting? Under BR the normal practice seemed to be a standard oil lamp for the tail, rather than using the electric lamp. e.g. https://zenfolio.page.link/iBGHi https://zenfolio.page.link/iXcMx Link to post Share on other sites More sharing options...
rynd2it Posted September 2, 2020 Author Share Posted September 2, 2020 On 31/08/2020 at 21:47, melmerby said: The one by the logo is red, AFAIK all others are white. The white lights approximate to normal loco headlights although the DRCs are usually depicted with the outer pair lit (express passenger). (I suppose some workings could be considered stopping trains and may need a different lamp arrangement alight) Which period are you depicting? Under BR the normal practice seemed to be a standard oil lamp for the tail, rather than using the electric lamp. e.g. https://zenfolio.page.link/iBGHi https://zenfolio.page.link/iXcMx That's very helpful, thanks. My model period is likely to be immediate pre or post- WWII, so still GWR, and the two railcars I have are the later ones, not the original streamlined one. One of them is the Express Parcels - I'll check the head codes for that one. Thanks David Link to post Share on other sites More sharing options...
RMweb Premium melmerby Posted September 2, 2020 RMweb Premium Share Posted September 2, 2020 4 hours ago, rynd2it said: That's very helpful, thanks. My model period is likely to be immediate pre or post- WWII, so still GWR, and the two railcars I have are the later ones, not the original streamlined one. One of them is the Express Parcels - I'll check the head codes for that one. Thanks David I have two of these DRCs One is the recent Dapol# version which comes with lighting already in place so there is little to set up. The other is an original Lima version*. I have fitted interior & cab lighting but not yet marker lights. *It's got a replacement Black Beetle motor bogie in place of the awful Lima pancake motor. # the Dapol one has the option of using a (dummy) tail lamp in place of the red rear light Link to post Share on other sites More sharing options...
rynd2it Posted September 3, 2020 Author Share Posted September 3, 2020 14 hours ago, melmerby said: I have two of these DRCs One is the recent Dapol# version which comes with lighting already in place so there is little to set up. The other is an original Lima version*. I have fitted interior & cab lighting but not yet marker lights. *It's got a replacement Black Beetle motor bogie in place of the awful Lima pancake motor. # the Dapol one has the option of using a (dummy) tail lamp in place of the red rear light I have just obtained a replacement motor for the Parcels version and I'm also adding DCC, the Hornby is DCC ready. And then converting to EM gauge as well. I did find a good link for head codes: http://www.uksteam.info/gwr/hcodes.htm so two whites would seem appropriate for the Hornby and maybe a single white for the parcels DRC. Link to post Share on other sites More sharing options...
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