The Moscow transit network, including the Moscow Metro, one of the largest subway systems worldwide, is moving to transit cards based on second-generation Mifare technology, Mifare Plus, an upgrade from Mifare Classic.

NXP Semiconductors, owner of Mifare and provider of the chips for the cards and readers, announced the move Wednesday, noting the Mifare Plus would enable the Moscow city Department of Transport to offer one card for use across the transport network, including the metro, buses, trams and, later, suburban trains, parking and road tolling.

The Moscow department of transport introduced the “unified transport pass, Troyka," or Troika, in February. As part of the upgrade, the department plans to install 25,000 machines across the city for riders to top up their cards.

Eventually the new Troika smart card application could be put onto NFC mobile phones, said NXP. Few transit operators to date have launched mobile NFC-based ticketing, however.

Russia’s second largest city, St. Petersburg, made a similar move in 2011 from Mifare Classic to Mifare Plus, with plans for a multimodal “Podorozhnik” transit card.

Moscow’s transport network “enables over 350 million trips per month,” said NXP. The Moscow metro handles up to 9 million passengers per day, and has used Mifare Classic cards and, starting in 2009, disposable Mifare Ultralight paper tickets for occasional or one-time riders. But the city’s transport department appears to be planning to phase out single-trip and two-trip tickets.

Mifare Classic technology is generally insecure and some transport authorities or operators have been moving to so-called second-generation Mifare, such as Mifare DESFire or Plus. Unike DESFire, Mifare Plus is backward compatible with Classic, which would enable transit authorities to more gradually upgrade terminals and cards.