Train lead singer Pat Monahan threw an “Easter egg” into the cover art for the band’s latest single, “Long Yellow Dress”: the Golden Gate Bridge.

“We're always going to be a San Francisco band no matter where we live,” Monahan, 55, tells USA TODAY. “That's just home. And so, yeah, it is a callback to the ‘Save Me, San Francisco' album.”Monahan is from Erie, Pennsylvania and currently resides with his family in Washington state. His band will tour the country on a co-headlining “Summer Road Trip” trek with REO Speedwagon that spans 45 dates from July through September. But no matter where the band is living or playing, signs always seem to point back to the 2009 LP that spawned “Hey Soul Sister,” “Marry Me,” and “If It’s Love.” “Save Me, San Francisco” turns 15 this October.

“I'm going to take the album out for dinner,” Monahan jokes of marking the anniversary. “We're going to get a very expensive bottle of wine. I'll drink it. 

“I don't really know if we have any big plans. I think it's mostly just, thank you to Train fans for welcoming us back after a few years of disappearing and then keeping the tradition going.”

Monahan recalls the “tough” period that led to the band creating the album. 

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“We were trying to write pop hits. It was about sustaining popularity and it failed,” he says. “And then I made a solo record that also did not do great. I learned a lot. And then it was kind of like, we need to reestablish what we care about.”The band’s consensus: they cared about San Francisco and “the music people wanted from us.” “Save Me, San Francisco” was certified three-times platinum in February.

Whenever Monahan writes a song, whether it’s “Meet Virginia” or the newest “Long Yellow Dress,” he’s trying to “write something unusual.”“‘Hey Soul Sister’ was weird with a ukulele. ‘Marry Me’ was weird; it was just me and an acoustic guitar,” he says. “(‘Long Yellow Dress’) doesn't sound like something that young kids are trying to do. It sounds like somebody my age should be singing it. And so I want to make sure that I act my age.”