News 12 is learning more about the MTA's plan to charge passengers who activate mobile tickets while on board the train — but key details remain unclear.

The agency says riders will face an $8 surcharge if they activate mobile tickets on board. Officials claim the penalty will only apply after a series of warnings, but they won't say how many.

MTA says the rule is meant to prevent what it calls "opportunistic fare evasion." Riders argue it's just another money grab.

If you get hit with a surcharge, you won't be able to use or buy a mobile ticket until it's paid.