I've noticed on a few occasions last week that when trying to swipe my Metrocard at a turnstile, the entire row of turnstiles weren't working. This happened Monday at Times Square near 40th street. It was as if there was a malfunction because one person in front me swiped and then no one at any of turnstiles could swipe. I went to multiple turnstiles at that part of the station and could not get my Metrocard to work and the same thing happened with other folks. I had to be somewhere and just said screw it and walked through the emergency exit since I have an unlimited Express Bus Metrocard. Other people started doing the same thing. A similar incident happened a few days later at 47-50th street, though I was eventually able to get my Metrocard to work. It didn't seem to be a situation in which the machines needed to be cleaned as I've seen 
employees do at Grand Central for example, but more like there was just a system failure for whatever reason due to so many people swiping during rush hour. Anyone else experience this? It was very strange to say the least.
The other thing that I'm curious about is when an entire subway station doesn't take a credit or debit card. What's up with that? That happened recently at Columbus Circle. I had to walk to Lincoln Center to the 
train station and refill my card there.