Not quite sure if this is the right place to post this query, so apologies if not.
I have an OO Gauge 2-H Thumper in BR Blue fitted with Legomanbiffo sound. I'm modelling late-1970s/early-80s around Portsmouth, so it would be used on the Portsmouth-Southampton or Portsmouth-Salisbury/Bristol/Cardiff services. I'd like to be able to add a 3rd coach to make a 3-H, but obviously would want to maintain the integrity of the electrical connections between all the coaches. Is there any existing coach model that I could add in the middle of the rake without too much needed to modify the electrics? Or would the electrics be quite a job?