It was open when I was there May 22nd the WDWinfo.com and the Disney.com website both have the attractions that are closed and the length they expect them to be.
The Railroad is open... BUT the toontown stop is closed. They are rebuilding the station there.... so the train only stops at Main Street and Frontierland
(dope... stupid me.... thanks Mom2R&D)
We rode the railroad on the 8th of this month and the conductor said the Toontown station would open in a week so it may be open now or if not then real soon.
The Toon Town Station was to reopen today but they had some delays (due to the ever reliable Summertime thunderstorms) and has been set back to June 26. So if your trip is after June 26 you should be set for a stop at Toon Town