All aboard the MTA’s mystery Internet train.
Computer-addicted commuters who ride the Metro-North to and from Grand Central could be surfing the Web during the ride — but they don’t even know it.
One car on the New Haven line has been secretly equipped with Wi-Fi, as part of a covert three-month pilot program the MTA has rolled out, The Post has learned.
The MTA isn’t telling commuters which car is connected because the system is “not ready for prime time,” spokeswoman Marjorie Anders said.
The train car has an outside antenna that receives a cellular signal from AT&T. Inside the car, a router converts cell service to Wi-Fi.
The MTA is currently reviewing three proposals to carry Wi-Fi throughout the Metro-North and Long Island Rail Road systems and to provide 32-inch digital screens in cars for advertising and real-time updates about schedules and delays.
Installing digital screens would cost up to $38,000 per car, according to an MTA request for proposals issued last March.