smaricic
Hello  & Welcome to the Forum!
Worn out locomotive? Really?
Motor doesn't run?
Wheels falling off?
Most probably your locomotive needs a thorough maintenance.
My newest locomotive a 1946 221 Dreyfuss Hudson just gets routine maintenencae.
My other is a 1937. l will admit it is starting to get a little zinc pest, but it too just receives
routine maintenance
Honestly, l dont own a Lionel that runs on O27 track newer than the Drefuss.
My other's, Lionel Standard Gauge & Wind Ups are 1917 to mid 30's

Ok, basicly You want a Scout. There's alot of them out there and reasonably priced.
lf you want something newer, the plastic MPC era loco's are available.
After those you start gettingmore bells & whistles...more stuff to break/wear out.
l see Scout's & Scout type locomotives, in very good to like new for 50 to 75$ all the time.
You can find Good,Used locomotives that your grand children will play with quite easily. Just dont get sucked into the auction fever & over pay.

check out our for sale/trade sub forum, maybe someones offering something you'd like..
my locomotives are in the gallery if you want a look.  Honestly, l didn't pay over $100.00 for anything.
Hope this is of some help.
Happy Rails!
dave