I have a MTH Trainmaster chassis from 1996, and just acquired a new shell for this locomotive. The shell has four working marker lamps powered by colored LED. Now I can't plug these directly into track power, so they will need to be stepped down. The chassis I have has the period QSI sound and control board, so there's no tap for LED power. How can I get these markers up and running ? They are wired in parallel, FWIW. Thanks.