Rod Stewart, known for decades as a consummate crooner, rocker, fashion plate and tongue-in-cheek sex symbol, is adding a new element to his image: serious model railroad builder.

The man who has hits dating back to the 1960s has put the finishing touches on a 23-year project that has landed him on the cover of Britain’s Railway Modeller magazine. It’s a far cry from Rolling Stone, whose cover he has graced many times.

The model is an ambitious portrayal of a gritty American city in 1945, representing a combination of New York and Chicago. It’s an artistic success, one that Stewart didn’t outsource but designed and constructed from start to finish, with some help with the electrical and computer connections.

“It’s the detail that I’m proud of,” Stewart said.

He is modest about hits like “Maggie May” but proud of his railway design skills.

“Absolutely amazing detail,” Stewart said. “There’s garbage in the streets, the windows are filthy, there’s everything you can imagine in real life is on the railroad.”

He grew up in London across the street from a railroad line and has been fascinated by trains ever since, taking mental notes on his extensive world travels.

When he got around to building a house in Beverly Hills, he added a room at the very top for his oversize model railroad. He would typically go up there for three or four hours at a time, quietly stepping away from his family and his musical responsibilities.

“It wasn’t a whim, it took a bit of planning, and 23 years later it’s finished,” Stewart said.

Now he’s got more time for music. The 74-year-old singer says that for some reason it’s easier for him to write songs than it used to be.

He’s promoting a new album — his best-known songs backed by the Royal Philharmonic Orchestra — and traveling in style, arriving for interviews in a chauffeur-driven Rolls-Royce with a hairstylist standing by to help with shape and volume.

If pressed, Stewart can come up with a few new artists that he likes, but he readily admits he’s “old fashioned” and prefers to listen to classics by Otis Redding, the Temptations and Frank Sinatra, who he started paying attention to when he was 9 or 10 because his parents were big fans. “The greatest,” he said of Sinatra.