Carriage lighting - where to start?

Dog Star

Dog Star

Western Thunderer
If this subject has been mentioned in WT topics befiore now then please excuse this old beare because the memory is not what it was.

So, we want to fit lighting into our carriages and we have no practical experience with this subject. We are building 7mm models of prototypes which were extant in the grouping era - say 1930 to 1940 - and that means incandescent bulbs rather than flourescent strips.

Ideally, the lighting is to be controlled by DCC decoders and with functionality to offer flicker free running. The DCC is to implement the concept of master carriage lighting switch. If possible, the compartment lights are to be dimmable whilst the corridor / vestibule lights remain bright. Functionality suggests that a pure function decoder with three or four outputs ought to be useful.

Who has any experience in this field and can suggestion either methods or products / suppliers?

thank you, Graham
 
Heather Kay

Heather Kay

Western Thunderer
Funnily enough, this is something I've been asked to consider for the broad gauge coaches I'm working on. I shall follow this topic with interest.
 
Softvark

Softvark

Active Member
This is a description of the way that I do it, which is not entirely applicable to your query, but may help. I wanted lighting inside my JLTRT Mk1 coaches running on DCC and I originally thought of doing what you suggest by using a lights only function decoder but in the end I decided simply not to bother with this at all and instead have the lights on all the time but at such a level that in normal daylight conditions you don't see them at all. When operating in reduced lighting they gently illuminate the interior. This makes things simple and saves cost.

I use a small circuit to rectify the DCC (use fast diodes such as UF4001, not IN4001 as they can't switch fast enough), a capacitor to provide flicker free running and then 12v LED strips as appropriate. The capacitor needs to be around 25v and use as much capacitance as you have room for. If you were to use one yellow LED strip (or individual LEDs) for the compartment lights, and warm white for the corridors, then you can set the different light levels with R1 and R2. The figures I've suggested assume you're using 12v strips but you'll need to experiment to get the best values for the desired light level.

I've put the little circuit in the roof of the toilets of the Mk1s where they are unobtrusive.

If you definitely want to switch lights on and off with different levels then you'll have to go down the function decoder route but this works for me.

Finally some suggested parts from Rapid electronics -

UF4001 diodes
12v LED Strips (you can cut these to your desired lengths

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Scale7JB

Scale7JB

Western Thunderer
If it helps, the DCC Concepts LED light bars have a variable resistor on the board to dim to your preference.. I'd be tempted to put a small push button under the floor of the coach.

For flicker free lighting, could a capacitor be wired into the pickup leads?

My one query though is the best option for pickup... Wipers to the back of the wheels?

JB.
 
Dog Star

Dog Star

Western Thunderer
Scale7JB said:
My one query though is the best option for pickup...
Click to expand...
I did not mention how we are approaching this question because I did not think that the matter was worthy of discussion. However, as JB has asked the question, here is what we are doing.

The kits are from JLTRT so we have metal bogies and resin underframe floors... with a brass interior floor. We are shorting from rim to axle of bogie wheels so that one bogie is live to the positive (or A) rail and the other bogie is live to the negative (or B) rail. A bogie is fixed to the underframe using a brass bolt into a brass insert in the resin floor so the inserts are live to different rails. Copper strips are laid on top of the resin floor and one end of each strip is bonded electrically to a brass insert such that the copper strips provide electricity to whatever controls the lighting.

We have put 20thou plastic strip either side of the copper tape and insulating tape over the copper such that the brass floor of the compartments does not short the copper.

As the current coach builds have a toilet compartment at one corner of the carriage body we have arranged the copper strips to terminate inside the compartment. The ends of the strips are "bolted" to the resin floor with 8BA bolts and sufficient bolt is left above the tape as to provide for a mechanical connection of the wire for the lighting. If we use DDC decoders then the compartment is large enough to hold the decoder.
 
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Dog Star

Dog Star

Western Thunderer
Softvark said:
This is a description of the way that I do it...

The figures I've suggested assume you're using 12v strips but you'll need to experiment...
Click to expand...
Thank you Julian, whilst not quite as desired the information is likely to guide where we go next.

I have spent several hours on the 'web and reading about lots of different products and very little of implementations. Unless anyone knows of material relating to fitting lighting to 7mm coaches then I think that I am going to have to get out the hot spanner, a sharp knife and make a mess... veroboard, resistors, LEDs shall be the staple.
 
Heather Kay

Heather Kay

Western Thunderer
Yesterday, at the Reading trade show, I intended to try to achieve some level of enlightenment (ho, ho) regarding lighting systems for rolling stock.

I have to say, I failed. However, having reread this thread, I think Julian's little circuit has merit - at least for the low light levels of an oil lamp in the roof of a compartment that I'm looking for.

I shall do some research and feed back when I have something worth showing.
 
Dog Star

Dog Star

Western Thunderer
Heather Kay said:
Yesterday, at the Reading trade show, I intended to try to achieve some level of enlightenment regarding lighting systems for rolling stock.

I have to say, I failed...
Click to expand...
What did you make of the Helmsman stuff?

Peter and I were impressed by the LEDs, for gas and electric street lights, which have illuminate a cone of light. The colour and intensity of the gas lights look good for GWR Dean coaches whilst the colour / intensity of the electric lights look good for late 1930/1940 carriages with electric lighting. We have bought the multi-pack for the electric lights, code FL-LED-M which is £1.00 per "bulb" ( so £8 per Gresley TK).
 
Heather Kay

Heather Kay

Western Thunderer
Graham, I didn't look to closely if I'm honest. The stand looked to much like Christmas lights! The only person who really understands this electrickery is Best Beloved, and he's sometimes quite sniffy about stuff. Being a complete numpty, I bow to his superior knowledge. He also felt their prices were too high :eek: I couldn't comment.

I took one of their leaflets, but it seems they're only really selling stuff readily available from other sources. We have quite large stocks of various LEDs, resistors and capacitors, so it seems silly not to try and make it from what's already here!

As I am keen to reproduce something closer to oil lamp light, I don't think gas or incandescent quite worked for me. Having explained Julian's circuit, Best Beloved thinks this might be the best option - if we can find a DCC layout or controller so we can learn about the shape of the DCC output to refine the flicker damping and so on.
 
Dog Star

Dog Star

Western Thunderer
Dog Star

Dog Star

Western Thunderer
@Rob Pulham has sent to me some details of a product which looks promising, thank you Rob ;) . The link is to a range of products and those which are interesting to me are "down" the page. As the current need is for products to use with existing carriages then we do not need wheels, hence those kits for lights without wheels are to the fore. At the bottom of the page is a reference to a two function decoder which is suitable for carriage lighting - the TCS decoder is available from DCC Supplies.

Of interest is the link to a pdf showing wiring for carriage lights using the products from CRT.
 
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