I wrote an open, collaborative, graphical GTFS editor called wikitimetable last year.
Alas the back end is in java, uses hibernate, is a first stab at Java, and doesnt really work.
The front end is of course javascript, is a first stab at Javascript, and ultimately doesnt work and while the UI design is good and I developed quite a few tools for shape generation and trip editing, it's wrong in so many ways that it's not a starting point for a joint effort either.
And it was all running on an old machine under my desk, which is pretty dumb (I didnt know AWS was free for dev), and due to some shunting about it's broke and as its nowhere near production level it's currently vanished from existence, but the code is on GitHub.
I did crawl what bus and train data I could find for Bangladesh, Burma, Thailand and Laos, also Sri Lanka, and then used my system (it's called Gee right now) to edit and clean this data up and so I had made genuine progress I believe developing the UI. I was publishing the GTFS to an array of OTP instances I had set up, indeed I was using OTP to generate bus route shape files by requesting road.car routing and importing the shape OTP made for me. This is also useful in fixing OSM data, I made quite a few fixes to the Laos road map doing this. I'd like to move away from route planning, I'm not trying to build a global route planner, there's plenty of people fighting that out already. But being able to test your GTFS via a route planner is actually a critical part of the edit cycle, so this may mean having to set up OTP for any distinct geographical zone.
I gave up on this early this year due to the deafening silence I get every time I mention this, but I am now having a go again, using NodeJS and Sequalize at the back and all the groovy stuff like Backbone for the front, and hosting it all on Amazon. And hopefully some of the bugs in Leaflet to do with large data sets will have gone away.
I am using GitHub via their API to manage release control of GTFS. Users fork their own copy of a GTFS to their own repository, have their own work copy inside the wikitimetable db, and then make a commit and then a pull request back to shared repository. All that happens under the hood, and controlled by permissions within GitHub. One issue is that while a non developer doesnt even need to know about this, other than obviously to make a GitHub account, a developer might not want to hand over write access to some GTFS editing app with next to no peer review. So you'd have to run all the pushing of your GTFS manually if you are a dev.
But I have just learned about this, which is why I came in here before another session on WikiTimetable 2.0.
http://www.wired.com/2015/08/nairobi-got-ad-hoc-bus-system-google-maps/?mbid=social_twitterIt claims there is open GTFS editing software but I cant find any.
All I want to do, other than have a bit of fun hacking, is to find out where the buses and ferries go from in far away places. If anyone else is looking to build an open, free to use, GTFS editor, please declare yourself.