If Lionel Richie were a train, Amtrak would be in better shape. Consider the track record for one of the hottest individual in pop music today:

His first group, the Commodores, has been together for 13 years since coming together at Tuskegee Institute in Alabama where the shy Richie by his own account was "an economics major, accounting major and overall Jack Benny." His studies have come in handy over the years as every Commodores album has turned gold or multi-platinum. After years as a major black act, the group attracted a huge crossover audience with such Richie-penned ballads as "Three Times a Lady," "Still," "Sail On" and "Easy."

Richie's first outside production job was with country-pop superstar Kenny Rogers, who was trying to expand his audience. "I thought he had everybody already," Richie laughed from the back of a limousine speeding along the Beltway yesterday after an hour-long stint on Channel 9's "Morning Break." "Kenny told me, 'I'm not going to be satisfied until I get some more people.' I didn't know where they were." The two settled on a Richie original called "Lady," and 15 million copies later, Rogers . . . and Richie . . . had tapped what they describe as "a universal audience." Richie produced and wrote four songs for Rogers' current smash album as well.

During the Rogers sessions, film director Franco Zeffirelli "called me because he wanted an instrumental theme like he had for 'Romeo and Juliet.' Hey, it takes a day to do an instrumental." Richie wrote the tune, then was asked to add some lyrics; then he was asked to produce an unknown singer who was eventually replaced by Diana Ross, who eventually ended up singing a duet with Richie. The tune? "Endless Love," now entering its eighth week as the No. 1 single in the country. It was Richie's first film assignment.

Last year, the songwriter set up his own publishing company for the first time; it was the top-grossing company of the year. He will be producing and recording his own solo album at Rogers' new studio in Los Angeles, Lion's Share (which may be a good description of their market position: Richie is the writer, producer or artist of six of the top 100 singles in the country this week).

Lion's Share is where "Lady" and the new album were recorded. "Kenny walked down the hall and said 'You know, I kinda like this place,' " Richie says in an accurately gruff-voiced imitation. "So he bought it," and is reportedly making $20 million of renovations. "My wife helped with the negotiations," Richie says. "Those two like to dibble and dabble, they're schemers forever."

Richie and Rogers have become close friends, with Richie even sending him a mule as a birthday present. After "Lady" hit the charts, Rogers called Richie, saying, " 'Well, Lionel, I can definitely see where my collaboration with you has paid off. I don't want to scare you, but tonight we sold out and there were four black guys in the front row.' And I called him back the next day and said, 'Kenny, I don't want to scare you, buddy, but right after I did "Three Times a Lady," I heard "Yahoo!" ' "

The key has been crossover, and with his production work, Richie has also crossed one of the most restrictive lines in the music industry. "Times are changing. Country-western artists are looking around for other collaborations with R&B artists. They're not that different, it's just the flavoring on top," he insists. "Both lyrics are straight to the point. There's no difference between 'Oooh, baby, don't leave me' and 'Take this job and shove it.' They're very direct and basic."

If Richie can keep from bumping into himself on the charts, he'll soon start work on the solo album everyone expects from him. The big question is whether he will leave the Commodores for a solo career that will provide the identity he lacks as a member of a group. Richie is cautious in his answer, saying "right now, I don't have that much going that I would blow the Commodores. I don't think I have to dynamite the group to be a successful Lionel Richie. There's 13 years of history there. We're intact right now; let's stay that way for the next 100 years. Anyway, communication is the key. We stay together more than we stay together with our wives.

"But right now, my primary love is to put my hands on Lionel Richie, I can tell you. I'm just crawling at the seams to walk into a studio, close the door and be the only one in there. Once I satisfy that itch, look out, I can do anything."

Despite success that has kept accountants busy and lawyers well-fed (his work is spread among five different labels), Richie retains a boyish enthusiasm. Although they were stablemates at Motown for over a decade, he and Diana Ross had never worked together until "Endless Love." "I used to walk down the halls at the company and Smokey Robinson would say, 'Hi Richie,' or the Temptations or Diana . . . I grew up with these people. I sit back sometimes and say, 'Is that my voice with Diana Ross?'

"I told my mother and father and grandmother that I have to be the luckiest guy in the world to have a hobby that makes me money. It's a little bit unfair."

Which of his singles is he rooting for right now? "I cheer for the song," Richie says with a platinum smile. "It's like a kid and I'm the parent. But as long as they all show up in the top 40, they're all good kids."