Actually it is easier to just walk by and keep moving.
Since most users of the busy metro system don't have NFC equipped phones, there's no reason for NFC to be installed.
In fact, I'd wager my current(non-NFC) equipped phone, that most users of *any* busy metro system don't even know what NFC is.
So...you have to install the "old tech" terminal anyway, or it is actually already there and paid for and revenue strapped gov trans agencies will not want to spend the millions to equip all the terminals with the NFC tech which will currently be used by less than 0.001 % of their users and by less than 10% of their users in 10 years.
In ten years they will have facial recognition and admission/billing based on that anyway. You just go to the trans office, give your contact/banking info, they take a pic, and you're on your way. Then they drain your account as you walk by the terminal.
NFC is a pointless waste.