@Mellow Hudson Mike, the opposite is true of open frame motors. They run measurably hotter on DC whereas in your case with DC can motors, the rectifier emits a negligible mount of heat barely perceptible to performance.
3 Rail O Gauge has been low voltage AC for over a century. There is essentially ****nothing in the 3 rail O Gauge arena that won't operate on AC. Stick with the establishment.
****There are always a few exceptions to the rule - there were some low cost sets that are DC only, but these are very very limited and of no real value to be concerned with.