SF Appeal reports that Muni will be replacing all existing fare gates at its underground Metro stations with TransLink-only fare gates (PDF) by fall of 2010, and it's possible Fast Passes will only be available electronically as well.

The 98 new underground fare gates, 40 fare vending machines and 16 new agent control terminals at Embarcadero through West Portal will largely be funded by money from the American Recovery and Reinvestment Act and federal grants. Outdoor vending machines might also be implemented at street level, for which MTA has set aside $3 million.

The new fare gates are projected to fix some existing passenger-flow problems, but we wonder how many new ones they will create. For instance, on TransLink's FAQ, they inform users that if a card reader can't read your card, it's always a good idea to carry a little extra cash on you. That's real reassuring for Fast Pass users!!

And how will this work for out-of-town visitors and other people who don't use Muni? There's also the whole Big Brother aspect of our every move being documented on some database. We guess this could come in handy if someone were to ever need proof of an alibi though...