For many entertainers, growing older is a liability; age is best kept a secret. Not for Alison Krauss (search). The 33-year-old says the years help deepen the well she draws from to sing about other people's lives.

"I think the older I get the more I'm able to relate to the songs I'm singing," she says. "I've been doing this since I was a teenager, and I had a very nice childhood. You're not going to sound like you've lived much if you haven't."

Tuesday, she and her bluegrass band Union Station (search) released their latest album, "Lonely Runs Both Ways."

Krauss describes it as their most emotional work yet, with songs that explore transition ("Goodbye Is All We Have"); lost love and loneliness ("Borderline"); and spirituality ("A Living Prayer").

Her somber, breathy vocals come across like a gray November day on the Gillian Welch/David Rawlings composition "Wouldn't Be So Bad" and on other ballads such as "Doesn't Have to Be This Way" and "If I Didn't Know Any Better."

The album's title is taken from the lyrics to "Borderline," and it sets the tone: "So you're on your own / Looking down the road / That goes only by one name / And you don't need the signs / To see lonely still runs both ways."

Krauss' band keeps things from getting too morose. There's the up-tempo Jerry Douglas-penned instrumental "Unionhouse Branch" and Dan Tyminski's twangy delivery on covers of Wood Guthrie's "Pastures of Plenty" and Del McCoury's "Rain, Rain Go Away." Ron Block sings on the self-penned "I Don't Have to Live this Way."

Four of the 15 songs were written by Krauss' friend Robert Lee Castleman, a former truck driver whose "The Lucky One," "Let Me Touch You for Awhile," and "Forget About It" were previously popularized by Krauss.

"They all sound like classics but they don't sound like anything else, which doesn't make any sense," Krauss said of Castleman's work. "But the next time the chorus comes around you know it. And you think you've known it your whole life."

Krauss spoke at her management office while her 5-year-old son, Sam, played in the next room. She was dressed casually in denim overalls and a T-shirt with her hair pulled up and wearing little makeup — more like a busy mom than a superstar singer who's won more Grammys (search) than any female artist (17, one more than Aretha Franklin).

"He goes with me everywhere, and that's awesome," she says of Sam. "I thought, 'Oh my God, how lucky I am that I can do that.' "

Hearing Krauss speak is a bit like seeing a picture of a favorite radio personality for the first time and finding that the face doesn't fit the voice. In Krauss' case, her speaking voice doesn't mesh with her angelic singing voice. She has a slight Midwest accent, which appears when she says something like "Oh geez."

She grew up a fan of classic rock bands like AC/DC and Aerosmith in Champaign, Ill., about 140 miles south of Chicago, and began playing violin at her mother's suggestion.

"My mom and dad wanted to put my brother and I in everything — art classes, sports. One of the things we were going to do is take an instrument for five years, and she chose the violin for me because my brother had the piano already. They bought me a book, and I listened to records. I made a tape of whatever song I wanted to learn and would play it like 35 times."

She soon was winning ribbons and trophies at bluegrass fiddle contests. She began performing in a bluegrass group when she was only 12, and by 16 released her first album, "Too Late to Cry."

As well as anyone, Union Station has managed to stay true to its bluegrass roots while appealing to country and even pop listeners. They've recorded the traditional "Down to the River to Pray" and Ralph Stanley's "Heaven's Bright Shore" as well as Bad Company's "Oh, Atlanta" and the Allman Brothers' "Midnight Rider."

In the process they've sold 7 million albums — an extraordinary number for a bluegrass band.

"They've turned a lot of people on to the music and caused a lot of people to want to go out and learn how to play," said Dan Hays, executive director of the International Bluegrass Music Association.

Of their crossover appeal, Hays said: "I don't think they're purposely trying to make music to appeal to a certain audience. I think they're just making the best music they know how to make and the music that's in their hearts. The music is what's most important to them. If it goes platinum, they're all the happier for it, but it's not their motivation."

While purists may scoff at the band's instrumentation, choice of material or their mass commercial success, Krauss doesn't worry.

"It's not that I don't think, 'Oh we're going to get nailed for that one,' because I think about that too," she says. "But the people that I want to impress are those guys I play with every night. If they like the kind of tunes I may bring to the table — and I know Ron (Block) feels the same way — if they like it, we're OK."