On average, more than 125,000 people pass through the 34th St-Herald Square subway stop every day. Of those thousands of commuters (including your Curbed editor), it's likely that most have had the misfortune to encounter a terrible stench that has emanated from the tracks for the past several months now.
But the source of the smell has remained a mystery—until now. The Wall Street Journal looked into the problem, and found that the culprit, according to the MTA, is most likely a sewage leak. There's just one problem: no one knows exactly where the leak is coming from. Per the WSJ:
MTA crews initially checked the station’s refuse room, a spokeswoman said. Then they checked a room where cleaning equipment is stored.
Crews later determined the odor was drawn in as trains enter and leave the station, pointing to a potential problem inside a tunnel leading to Herald Square, she said.
MTA crews haven’t found leaking sewage in the station, she said. It isn’t clear whether there is a damaged sewer main in the street or a building sewer line could be at fault.
So basically, it's a good news-bad news thing…but the bad news is pretty, well, crappy. (Sorry.)
A similar issue recently plagued the Myrtle-Wyckoff St station in Bushwick, which services the L train; the MTA has pledged to fix the problem, so Midtown commuters, there's hope for us yet.