First seen in "Star Trek III : The Search For Spock", the Excelsior was claimed by Sulu to have the new 'transwarp' drive. The lack of such a technology within the federation has led to the obvious conclusion that transwarp was a failure, and I devoted much of the text to this. I like the idea that Scotty's sabotage actually saved the Excelsior from destruction - even when our heroes are doing wrong they're doing right!

The rest of the entry for the basic Excelsior is pretty much what we know, or can directly infer. For the modifications seen on the Enterprise-B in "Generations", I suggested that she was a response to the 'cloak-fire' Bird of Prey because it seemed reasonable that the Klingons would have persued this technology after Star Trek VI. Having the E-B subtype as a more specialist ship than the normal Excelsior is a reasonable way to explain why we have seen relatively fewer of these ships during TNG.