jQuery is a library where rails is a framework. but I will agree, a lot of developers are likely to use it as a crutch in lieu of fully understanding cost vs benefit in your app. if this is the case, then you very might well need jquery.

node express is the rails ;)

Node express is Sinatra. There is nothing even close to Rails in the JS world, Meteor is getting closer every day, though.

Well, there is Sails.js[1]

[1]: http://sailsjs.org