The Metropolitan Transportation Authority finally released its public bid for a mobile, contactless ticketing system, but don't expect to use your iPhone to pay for a ride on the A train anytime soon. After it picks a private vendor to install the new fare payment system, the MTA says the contract will have a duration of 69 months, which means it won't be up and running until at least 2021. And given the MTA's track record for completing projects on time, probably even later than that.

"a contactless bank card, smartphone or any mobile device"

So how will it work? In the request for proposals that was posted today, the MTA says it will be "an integrated, reliable and convenient fare payment and collection system" that allows bus and train customers to pay fares by tapping a contactless bank card, smartphone, or smart card against an electronic reader. In other words, say goodbye to the iconic yellow MetroCard, that's been around since 2003 when it replaced subway tokens. And say hello to something completely different.

Expected price tag: $450 million

Private vendors have until June 23, 2016 to submit their proposals to the MTA. The agency is allocating at least $10 million for the project, though it will likely cost far more than that. The MTA's board of directors said in 2014 that they expected the project to cost $450 million.

The idea of mobile tickets on your smartphone for riding the subway in New York is certainly exciting, if not daunting, given the financial and infrastructural challenges that lie in the way. The MTA has 34 train lines (and one more under construction) and 469 stations, both above and below ground. Each station has a dozen or more individual turnstiles that would have to be modified or replaced completely to accommodate the new fare payment system. It's a logistical nightmare, but one that will need to be done if the MTA is to move into the modern era.

The MTA has toyed with the idea for years — it signed a deal with MasterCard in 2006 to test a new RFID card payment scheme, and conducted a second pilot with MasterCard in 2010 — but it wasn't until New York Governor Andrew Cuomo announced late last year that he wanted to usher the subway system into "the 21st Century" that the idea of a new fare system gained renewed traction.

The MTA's board of directors said that replacing the MetroCard would take at least five years. Under the governor's accelerated time schedule, installing a new payment system will begin in 2018 — and even sooner for the region's two commuter rail systems, the Long Island Rail Road and Metro North, which will get mobile payments in late 2016.

A number of companies are already vying for this lucrative contract, including MasterCard, defense and transportation contractor Cubic, mobile ticketing firm Masabi, and others. MetroCard assisted the MTA in its previous pilots, and Masabi is working on the new fare systems for MetroNorth and LIRR, so those two firms may have a leg up. The MTA will likely gauge each bidders experience in installing modern fare payments systems in other cities before making a decision.

The inefficiency of the MetroCard made headlines recently when Hillary Clinton had to swipe hers five times before making it through the turnstile. If she wins the election in November, it won't be until her (theoretical) second term before the replacement system is in place. Which means another chance for the candidate to get it right on the first swipe.