@boomer0622 posted:Do these older sets run off a regular AC transformer or are they DC ?
It depends on the particular set and the year it was made. Lionel did a few sets that came with a DC power pack and had locomotives equipped with DC can motors wired directly to the track pickups. I believe the majority of the sets were the typical open frame AC motor however, at least until the circuit board type "E-Units" came into existence. I can't speak to which years the various transitions occurred in however.