Subway,Affair With A 20 Year Old Female Student the world's largest fast food chain, is launching a new loyalty program, called Subway MyWay Rewards, that will offer customers surprise treats and tokens that eventually mature into dollars.

The move is a step toward earning more customer love, as well as making the Subway experience more digital -- since it comes with a mobile app refresh.

Subway MyWay Rewards launches in the U.S. and Canada in March and will be available at 28,500 restaurants. With Subway's scale, it'll be one of the largest loyalty programs in the world, though MyWay is far from Subway's first effort in this arena. For example, the chain previously offered free meals with a punch card system called Sub Club. That was discontinued in 2005 in part due to fraud, as Wired reported. The new system tries to avoid that by making it all mobile.

"We really designed the program with the consumer in mind. You don't have to read the fine print," Subway's Chief Digital Officer Carissa Ganelli told Mashable of MyWay Rewards.

Here's a look at Subway's new mobile app for tracking rewards:

Subway's offer of surprises is easy to understand and sounds a lot like Panera Bread's MyPanera, but the tokens are a bit more complicated. (Fortunately, they aren't related to cryptocurrency or ICOs or anything like that.) Call them points, if that helps.

Here's how the tokens system works:

• For every dollar customers spend at Subway they earn 4 tokens

• Reach 200 tokens and receive $2.00 in Subway credit

So, if Subway customers wanted to maybe earn enough tokens to cover an entire Subway sandwich. Let's just say one that costs about $6.00. That's 600 tokens, which means spending $150. Yeah, it's not easy, but we're talking about free sandwiches here. The rewards also can be applied to cookies, drinks, salads, soups, or whatever else they're serving up at Subway.

Thankfully, keeping track of rewards is pretty easy. MyWay Rewards members can look them up on Subway's website, the mobile app, or ask in-person at a Subway location.

The program's structure is what the people — at least those who Subway surveyed — asked for, according to Ganelli.

"The $2 threshold was something that’s going to absolutely enable us to reward our members more frequently," Ganelli said.

In addition to instituting a $2 reward, Subway gleaned from its customer surveys that people want surprise rewards.

"You won’t know when you’ve earned our reward until you’ve earned it," Ganelli said and shared an example of me earning a free drink and being notified via Subway's mobile app. "That’s awesome. I got a present today because who doesn’t like surprises of delicious stuff?"