TTC riders can now use Presto electronic fare cards on streetcars, as long as they're travelling on Spadina Avenue.

Starting Sunday morning, Presto card scanners were installed and working on two of Toronto's new streetcars that travel up and down Spadina.

A third streetcar is in the testing phase, and is expected to hit the tracks in the near future.

Presto cards are reloadable passes that are meant to replace municipal-specific transit passes. Implemented by Metrolinx, the passes allow users to transfer seamlessly from transit systems with the use of a single card.

Currently, the cards can be used in Brampton, Burlington, Durham Region, York Region, Hamilton, Mississauga, Oakville and Ottawa. They are also accepted at all GO Transit stations across southern Ontario, and at 15 TTC subway stations.

The cards work like a debit card. Users tap their card to a scanner to pay a fare, rather than having to count change or switch bus passes each time they enter a new city.

All subway stations are expected to be equipped with scanners in time for the 2015 Pan-American Games in July, and all buses and streetcars should have the scanners installed by 2016, according to Metrolinx.

For now, TTC users who start their day on the Spadina streetcar line will have to take a paper transfer from their driver after scanning their pass, if they need to switch to another transit vehicle.

Those who don't need a paper transfer can board streetcars from the back doors, tapping their cards at the scanners located there.