Hi Roy!
As others have posted, I don't think you actually require a connection between the engine and the water car. However, doing so would improve the electrical pickup which would mean fewer interuptions to the sound decoder. You would want to pick up track power from the engine and route it to the water car. The motor controller would not be linked in.
I make my own connectors out of IC (Integrated Circuit) sockets like this:
http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=CA&WT.z_homepage_link=hp_go_button&KeyWords=ED3314-ND&x=16&y=21
I use a razor saw to cut them into however many pins are required (in your case - 2). They plug into each other just like the IC plugs into the socket and the connection is quite firm. My suggestion would be to mount the female plug on the back of the engine beside the coupler and the male plug on a lead from the water car. That way when you want to run just the engine you won't have a plug dangling behind. You will have to mark polarity on the plugs. Go easy with the soldering iron or you will melt the plastic holding the pins.
It might be simpler to just add some extra weight to the water car to keep it firmly on the tracks.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
Thanks guys it seems this is a lot easier than I had thought. I did not realize a sound only decoder could be treated like a consist between a pair of function decoders in two seperate locos. As I said earlier I don't know much about DCC capabilities but the more I learn the more I appreciate the system. One reason I gave up this hobby over 50 years ago was that I had a very nice scratch built GG-1 that had two 6 volt open frame motors that I was never able to syncronize properly. That would be easy to do with DCC but back in the 50's it was a major headache. I was a teenager back then, bought an old car (my first- a 1930 Essex) and the model railroad lost its funding (I never got that old Essex to run well either).
Roy Onward into the fog http://s1014.photobucket.com/albums/af269/looseclu/
Yep. That is what I would do also.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
LooseClu,
If I were in your position, I would install the sound-only decoder and speaker in the water car - the biggest speaker I could get in there while still allowing space for the decoder. I also wouldn't bother running wires between the loco and the trailing car. The pickups from the wheel wipers on the water car should be connected directly into the sound decoder, and that's it. Then, all you have to do when you want to run your locomotive is to couple the water car behind it, consist the locomotive's decoder with the sounder and away you go.
That's my anyway. Hope this helps.
Cheers,
tbdanny
The Location: Forests of the Pacific Northwest, OregonThe Year: 1948The Scale: On30The Blog: http://bvlcorr.tumblr.com
I have four geared steam locos, three are equipped with DCC motor/light decoders and one is Tsunami 750 function and sound equipped. The cost of three more Tsunami decoders is a bit daunting and there is very little room for speakers in the small Climax or 2 Shays. I thought if I put a sound only decoder in a water car that could connect to any of my now silent trio my budget could remain in the black. It got confusing when I tried to figure how to wire that setup so that the engines could run with or without the sound decoder carrying water car. I am also unaware of what is the best solution the temporary connections of the leads between the loco and the water car (that would be easy to unhook/hook up). How many leads would be needed? My knowledge of DCC is very limited. How does the function decoder communicate with the sound decoder. Does power to the sound decoder come from the function decoder or does it require separate power input? The water car will have wheel wiper pickups, does that input go to the function decoder or the sound only decoder? I know that’s a lot of questions and I would appreciate any answers/suggestions you can give me with this.