Capturing Walled Cities

I've always had a problem capturing walled cities.  I know the usual ways
to
get around them; artillery to shoot over the walls, spies to knock them
down,
or nukes to wipe out all the defenders.

Today I was playing the Revolutionary War scenario in Civ II Multiplayer
Gold,
and none of those options are available.  Rather than lose hordes of
troops
invading Boston, I decided to just park a unit in all the squares around
the
town so they couldn't use them, and starve them out.  Not only did it not
work,
the city actually grew from an 8 to a 9 while I had this siege in place. 
What
gives?