Arriving at the twilight of the post-grunge era, Train combine rootsy mainstream rock with tried-and-true classic rock, an aesthetic epitomized by their breakthrough hit “Drops of Jupiter.” Taken from the 2001 LP of the same name, that international smash gave Train a career, but the group turned into superstars in 2009 when the breezy, sextuple-platinum-selling “Hey, Soul Sister” established the combo as adult contemporary superstars. In the 2010s, the band continued to find success both at home and abroad, issuing a string of Top Ten AC hits (“Drive By,” “Angel in Blue Jeans,” “Play That Song”), while taking the occasional detour, such as the sunny seasonal set Christmas in Tahoe and covering the entirety of Led Zeppelin II. Despite these left turns, Train’s heart remained firmly in mainstream pop, something they tacitly acknowledged with the throwback title and vibes of AM Gold, their bright and cheerful 2022 album.