ANR Freight System Inc. will close half of its truck terminals and lay off more than 3,000 employees in a bid to stem sharp financial losses.

Coastal Corp., the Houston-based energy giant that owns ANR, said it will shrink the truck line from a nationwide company to a regional carrier serving

mainly the Great Lakes states."We've tried various strategies to turn around the business, but they haven't worked," said J.A. Bailey, a Coastal spokesman. "We felt something had to be done to reverse the losses."

ANR is the nation's 10th largest trucking company, with more than $416 million in 1989 revenue. The Golden, Colo., freight line lost $22.2 million last year, including $12.1 million in the fourth quarter.

"We believe ANR will be more streamlined and efficient by focusing on those regional markets where we have traditionally been a strong performer," said Joseph F. DeBella, ANR's president.

Many financially ailing trucking companies have tried to save money by reducing service to a core group of states. The strategy usually does not save the company, as worried shippers seek healthier carriers.

Most of the troubled truck lines close within a year of the cutbacks.

Pilot Freight Carriers Inc. of Winston-Salem, N.C., and Brown Transportation Co. of Atlanta each down-sized their companies in 1989, but both failed several months later.

Bowman Transportation Co., also of Atlanta, was expected to close its main freight division today after an unsuccessful bid to trim operations earlier this month.

"When shippers see service pared back, it begins to feed on itself," said George Morris, a transportation analyst with Prescott, Ball & Turben in Cleveland.

"Companies would rather get their freight delivered than be a martyr and try to keep someone in business."

ANR will close 113 freight terminals and retain 104. About 60 of those to be kept are in eight states bordering the Great Lakes, including Michigan, Illinois, Wisconsin, Indiana, Ohio, Minnesota, western Pennsylvania and western New York.

The truck line will continue hauling freight in some long-haul markets and will keep about 40 other terminals beyond the Great Lakes region. Most of those freight facilities are in California, Texas and the metropolitan Philadelphia and New York areas.

The company also will keep terminals in a few other busy transportation centers, such as Memphis, Tenn.; Jacksonville, Fla., and St. Louis.

Unlike other troubled truck lines, ANR is owned by a financially strong corporate parent that could help the trucking company convert to a smaller operation.

"Coastal has $8 billion in assets, and that does make a difference in this case," Mr. Bailey said.

Coastal's decision to cut operations came less than a week after the proposed sale of ANR to Transcon Inc. collapsed.

Transcon, a Los Angeles trucking company, reached a tentative agreement with Coastal in December to buy ANR. But Transcon had trouble financing the deal and Coastal called off negotiations March 21.

Coastal will continue to seek buyers for ANR and said interested parties might be more attracted to a smaller trucking company.

"Coastal can't find a way to get out of the trucking industry, so they're getting as far out as they can," Mr. Morris said.

By keeping ANR in business, Coastal avoids paying pension plan liabilities that are triggered when a Teamster-organized trucking company closes.