After much trial and tribulation, I successfully converted 5 Marklin coaches and one Roco Tegernseebahn coach with LED lighting, current conducting couplers and little 1:100 sitting people.
The master coach [ one of the 42892 set ] with Marklin pickup shoe and earthing contacts [ 73404 ] plus the 72020 conductor kit ] got completed today with the addition of 57 or so little sitting people. This coach is crowded but not all seats are taken. Other coaches will have more empty seats.

In this picture you see the people as well as the LED strip with a 1000 Uf capacitor at each end of the LED strain. The body of the coach is attached via a 2 pin plug, using up the 2.5 mm JST plugs I got by mistake, this is attached to a micro bridge rectifier which is wired to thje LED strip. The green wire is the connector between the close couplers.

The above picture shows my own made up wheel pickup. I used shim brass cut into small rectangles which I centre punched then push a hole through where the cent punch went. I then properly shaped these to enable the wheels to run free [ they are fitted at the end of the axles, as there is plenty of free play that can be used ]. The pair of brass contacts were soldered to a feed wire which went up to the 2 pin connector. The second coach in the 42892 set has this axle pickup , and these coaches are set up to take the proper Marklin current conducting coupler set up 72020.
All coaches are complete, self contained lighting modules. They just need current from the track, provided via the close couplers etc.

The 2 x 3 axle coaches from the 4289 set take the close coupler setup 72020 except the pick base plate that comes with the coach has to be used [ special shape that wont take the base conductor from the 72020 kit, which meant soldering a power wire from it to the JS 2 pin connector.
This whole process went well until I got to fitting the capacitors. They were too big so ended up soldering two pairs of 470 Uf capacitors together in one case and soldering them to the pickup wires.
During this process, I tested each coach and all went well in the end but it took a while before I could get all these bloody couplers to couple together. Very frustrating.

Next was the other 3 axle coach, I didn't have any 470 Uf left, but had plenty of wee 100 Uf ones. I managed to solder 10 of them into a cluster which did fit in the end of the other coach without being too obvious.

When it came to the 4 axle coach in the 4289 set, I found they were never intended to take the current conducting couplers so I had to make my own couplers by removing the pre-un-coupler from a standard close coupler and feed a piece of shim brass through it. The first attempt wasn't so good because the brass shim was too thin so started again with a thicker shim. I was able to make the tail longer than the genuine coupler in order to solder a wire to is and then bed it out of the way. The first one was trial and error and I would not do it that way again.

Next came the Roco Coach of the same type as the 4 axle coach in the 4289 and 42891 sets. There was no room to fit the current conducting coupler without making special conductors with long tails. Also, the feed wire from the coupler had to route through the very end of the coach. This meant I had to loop the wire under the chassis to give a lot of free movement to the coupler. I also made up the wheel pickups and had to drill through the pivot point on the bogey to pass the earth wire through as there was no provision for this. I fitted everything up including 2 x 1000 Uf capacitors as before. When testing this little bugger of a thing I was greatly frustrated because it kept on derailing. Of course, it was my fault so it came to bits many times before I realized the bogeys on the bloody thing were at fault. the sharp edge on the bogeys were grabbing in to chassis on turns. I ended up using a Stanley knife to reshape the sharp edges. When the bogeys rotate on this wagon, they are virtually touching the chassis. Marklin at least make provision for this and have quite a gap between the top of their bogeys and the chassis.

In the above picture you see all coaches lit up. There is absolutely no flicker. I did have some problems with coupling contacts making and breaking but that is all cured now.
Yesterday the 400 wee 1:100 sitting people arrived, but I have to wait for my 6 year old grand daughter to come and fit those . She made a good job of one of the 3 axle coaches when I told her what I was doing. Bloody good show and my fingers are too big. BTW, the figures are held to their seats with blue tack.

More pics to follow. I need a break.

Lesson learned. Solder all capacitors, bridge rectifiers and 2 pin connectors wires etc directly to the LED strips. That way you have a complete removable module fitted in the roof. The strips are nor very sticky so used blue-tack to help hold them in place. Helps to make everything repairable if you stuff up [ which I have done in the past. ]
Dereck

ps. number 14 really struggles to get all six coaches running. I have to dial up the MS2 to about 3/4 before it will move off, then back it off a bit. All those pickups do cause quite a bit of combined drag. That surprised me because it is a heavyish loco with 4 axles powered.

ANALOG GUIYS. THIS WORKS FOR ANALOG AS WELL. [ BRIDGE RECTIFIER ]

Edited by user 12 November 2020 22:28:43(UTC)  | Reason: Not specified