ROTFLOL!
How did you "change the rear lights"
Is the older locomotive a single motor? I saw someone talking about a single motored Aerotrain locomotive, but the MTH site appears to say dual motored for all the variations.
IT's doal motor but the rear motor is on a single axle truck. I know someone who added 3 lbs of weight on the front truck for better operation to pull all the nine cars.