Thanks to all who replied.
To Virender Dogra:
Yes, http://127.0.0.1:3000/ shows the Rails application
To Curt Hibbs:
After clearing the cache, yes, the browser shows the Rails application.
(I'm using FireFox, configured to "remember nothing", but obviously I
missed something.)
To Dave Burt:
Yes, there is a Listen 3000 in Apache's httpd.conf. After replacing
3000 with something else, /localhost:3000/ now gives me the Rails
application.

I'm off and running on Rails (until the next bump). I can't wait to
find out what all this interest in Rails is all about!
gk