No, it mainly depends upon wether you want to have them lit always, or be digitally controlled by adding a funtion decoder in one, or use a loco. with a digitally switched coupler to activate them.

Thanks both for your comments.

I had already decided to use the Marklin LED strips as they are designed for the purpose and fit very well. I have 10 coaches fitted. I did think at first to have one slider per set of coaches with the others linked through conductive couplers, but wouldn't the problem be that when the coaches were parked in the siding, then the lights would on all the time the track had power to it. Also I would need to ensure that the coaches were not swapped around and I ended up with a rack of coaches without a slider

Rather is would be good to have a conductive coupler on all the coaches and also on the locomotive so that when the locomotive connected to the coaches, the lights would come on. Is that possible or does the locomotive have to be modified? all my locos are digital

Thanks

Alex

You have made your choice already, but anyway: I used LED strips with a power pack, current-conducting couplers and one slider from Märklin. I saw no need to buy Märklin ground return thingies as they are quite easy to build. The pillars Jean mentioned are an obstacle, but not a critical one.

Hi
Personally, I also like to control the coach lights from the locomotive decoder when possible. Some few Marklin locomotives have this option from the factory eg 39781
and in some cases, you can fit it fairly easily. eg as I did here :https://www.marklin-users.net/forum/posts/t45809-Marklin-39052-BR-05-AUX-3-and-current-conducting-coupler

other times it makes more sense to install a decoder in one of the coaces, or just have one coach with a slider.

note that when you use a decoder it's recommended to use a relay if you are using lights with condensators etc. This is because the condensators can have a bit high initial power draw, that can overload the decoder.
eg from the factory the 39781 are powering the coupler through a "photo relay" to protect the decoder. the recommended 43141 coaches for that locomotive come without a slider. When the lights in those coaches are activated the initial current draw is quite high. I measured a short peak at just above 4 A

Thanks again everyone for your valuable comments and suggestions. - there are clearly multiple ways in which passenger coaches can be lit.

Having played with them for a day or so, I agree with RHFIL, the current conducting couplers from Marklin are a real pain and don't couple/uncouple easily. My electrical skills (and rubbish eyesight) are such that I wouldn't feel confident in doing significant alterations to the locos, especially at their current cost, so I'd rather not start having to add/change things in that area!!

I will do more research but I guess it might mean reverting to battery powered lights inside each coach. I have found one, an led strip with a movement switch so that the lights come on when the coach is moved, and go off after a short period when it is parked up, it just depends on how well they fit inside the coach roof and how often the battery will need replacing.

Alex

???
They couple and uncouple the same way as a normal KK couplings, i installed them on all my coaches and have no problems what so ever with them.
I am talking about the KK style couplers in this case, not the permanent draw-bar current conducting couplers.....

Equipping the lok's with them is a bit more tricky and requires some tinkering skills to set them up...

Regards

Jean-Pierre