Update, May 7: "We are going to be open tomorrow from 11:30; we just have inspection," I was told by telephone. Thursday, May 8, it is. Previously:
"Do you know when they're opening?" asked the fellow in the sheriff's hat. The two of us were taking the noontime breeze on Ninth Ave.; I'd just emerged from a look at the new Hallo Berlin Express. The workman behind the counter wouldn't say, I told the "sheriff," but moments later a moustached stranger made an appearance. "May 1," said the stranger (who identified himself only as a partner) before he moseyed inside, perhaps to attend to the tap lines; unlike the famous food cart near Fifth Ave., Hallo Berlin Express will be serving beer with its brats. See you 'round these parts again soon, stranger.
Update: Opening day has been pushed back from May 1 to May 7, as you can see from the sign below. Despite the signmaker's uncertain hand and lack of ease with ordinal numbers, another stranger (unshaven, but moustache-free) confirmed the new, later date.
Hallo Berlin Express
744 Ninth Ave. (50th-51st Sts.)