She left on a train in November 1996, and tonight on "ER" (10 p.m., NBC), Dr. Susan Lewis (Sherry Stringfield) returns.

 

For Stringfield, it was a self-imposed exile. The actress wanted out of the job. She wanted time to have a life, to live in New York, to escape the glare of the Hollywood lights.

 

Three years ago she married journalist/author Larry Joseph ("Gaia: The Growth of an Idea") and six months ago she gave birth to their first child, Phoebe. Now, she's ready to check back into the E.R.

 

Despite her declaration when she left that she couldn't imagine returning, Stringfield said her reason for scrubbing in again is simple: "I changed my mind."

 

"I really felt like acting full-time again," Stringfield said in a phone interview earlier this week. "I hadn't really felt that way, and when I did, it just made sense for me to go back to 'ER.'

 

"When she left "ER," her departure was accompanied by a list of restrictions that kept her from working as an actress unless she got permission from "ER" producers until the end of her contract 2 1/2 years later.

 

"They didn't believe me that I was leaving to get a life," Stringfield said. "They thought, in a very business sense, I was doing it to further my career or start the 'Sherry' show or capitalize on the 'ER' fame. ... As it turns out, I think they saw I was true to my word."I

 

n her time away, Stringfield has taught drama courses and taken up photography. Her "ER" bosses prevented her from taking one role in a non-NBC TV movie, but there are no hard feelings. They'd been trying to get her to return to "ER" since she left.

 

"They asked me to come back for a couple years and then I was pregnant and then they didn't ask, and then I was like, you know, I want to go back," Stringfield said. Now she's under contract for three more years of "ER."

 

Her return may put an end to the question she was asked most frequently for years: Why did she leave what was then the No. 1 show on television?

 

"It's amazing how everyone has an opinion on how you should live your life," she said. "I can understand that [a role on 'ER'] can appear to be a very coveted position. ... I kind of came to understand they didn't have a full understanding of an actor's life. [We] have a million different jobs and we're all used to it. It's rare to have a job more than a year or two."

 

In the "ER" story, Dr. Lewis has been living in Arizona near her sister while working in a more upscale hospital. Lewis returns to Chicago for a visit and drops by the emergency room to see her old friends.

 

It takes Lewis some time to remember what working at Cook County General Hospital is like, and Stringfield still isn't readjusted to working with fake blood.

 

"I do not like blood. I cannot believe I do this show half the time," she said. "And now it's even worse. They have this prosthetic, fake chest cavity they crack open. I almost passed out when I saw that one. Oh, it's so horrible. I could never be a doctor."

 

She just plays one on TV.

 

by Rob Owen