Chris
Hello & Welcome to the Forum!

The 8602 is a basic locomotive,  if it has been cleaned and lubricated properly, should have plenty of power to pull several cars quite well.  If yours has traction tires and they're missing, that might explain the lack of power.

Pre/Post War saw a change from tinplate & die cast to plastic & die cast after WW2 for the manufacture of trains.

To add additional power feeds to tubular track you use a "Lock On".

I prefer tubular track, but it's a chevy vrs. ford type question....

I hope this shed's a little light in the tunnel for you.

Happy Rails!
Dave