Hi, question for the decoders and electronic masters.

I'm planning to put leds to the cars of a long Talgo train (6 to 8 cars). For doing it I already have a
function decoder, and I don't want to use special connections between the lok and the first car for passing
current from the lok to the cars.

At first the thing seems not to be too difficult. I already have a function decoder for the last car, to
which I already have put pickup shoe.

The problem I have is that when the lok will go where a signal is, the signal will become "red",
thus, using the classic way of Märklin, it will cut the current in the block just before the signal,
which will imply that, being the pickup in the last car of the train, the leds will switch-off during the
time the pickup wil be in the "without-current" block.

A first solution would be to put the pickup shoe in the first car of the train, but it would imply that when the train stops in any red signal, the cars will light off.

Following solution could be to have two pickup shoes, one in the first and a second in the last car and both connected to the function decoder, but this would pass current to the block that (theoretically) should be without it.

The last zsolution I'm think about is to have a second function decoder in the first car of the train, and this one taking current from a pickup shoe in the first car, and connecting the function output of both decoders. With it, the leds will always receive current.

My doubt is if connecting the output of one decoder to the output of the other (which will give current where it is supposed not to be) will damage any of the two decoders. So, I'm thinking in putting a diode (1N4001, for instance) in each of the outputs to be sure that the current only flows in the appropiate sense.

Do you feel it could be a good solution? Or might it be that the decoders already implement a diode in their outputs tobe sure they are not damaged and, thus, my diode is not needed?

Thanks for any feedback.

Javier

This will not work with alternating polarity on the track (e.g. 3R analogue, 3R digital, 2R digital, with 2R analogue lights will work in one direction only).

It works to connect two outputs of a single decoder. If the loco has only one lamp, that lamp can safely be connected to both front and rear output of the decoder.

I hope it will also work if two different decoders are involved. I cannot see a reason why it shouldn't work (but I give you no guarantee if I missed something and you get blue smoke out of the decoders).

Decoder outputs have transistors - and transistors work similar to diodes.
Maybe one of the electronics gurus can comment whether additional diodes would be better here.