If at first you don't succeed, swipe, swipe again. But not at a different turnstile. That's the message the Metropolitan Transportation Authority says it must get to the public amid a glitch that's been uncovered with MetroCard turnstiles. They are deducting two fares - not one - when a straphanger misswipes and, thinking the turnstile is broken, switches to another turnstile to swipe again.

The problem occurs when a customer lifts the MetroCard out of the slot too early; the first turnstile deducts the $1.25 fare but doesn't complete record-keeping details needed to close the transaction and let the customer through. If the passenger then moves to another turnstile to swipe, the debiting process begins anew.