Griping to the MTA just got a whole lot easier.

The transit agency is taking a page from the city’s 311 playbook and launching a three-digit, one-stop line for everything from lost-and-found queries to MetroCard malfunctions.

The newly revamped 511 system made its debut yesterday, eliminating 117 separate phone lines that previously frustrated straphangers.

The line will also provide bridge- and tunnel-traffic updates, pricing info and service changes. And since it’s connected to the state’s transportation hot line, commuters can also call to find out which roads are congested.