Three years ago my sons purchased a HO steam train set called Pacific Flyer for me. It runs great and I love it. Recently I was given another HO train set called Old Time Village Express. I believe this set is about 10 years old and came factory sealed. However when comparing the two sets I noticed they are different in size BUT both are HO scale. The 1st set is a 060 while the 2nd set is a 440.

My questions are, why is the 440 locomotive smaller than the 060 locomotive? AND Why is the motor for the 440 locomotive located in the tender with a drive shaft and not in the locomotive itself? (like the 060 locomotive is).

Could this be due to the age difference?
What size is the current Jupiter Old Time locomotive and where is the motor located?

Thank you for any help you can provide!