POUGHKEEPSIE, N.Y. — IBM unveiled a new generation of mainframe computers Wednesday that it said would double the power of its most profitable machines and cement their position at the center of office computing.

The announcement, made at the company’s U.S. mainframe factory, was billed as the most important rollout for International Business Machines Corp. in 25 years.

The success of the new machines is crucial to the world’s largest computer company because it derives about half its income from mainframes and associated equipment and software.

The move was well publicized in advance, but industry experts were still impressed with the scope of the company’s new strategy.

The announcement crystallized a new vision for how IBM believes mainframe computers should fit into today’s decentralized computer systems, where desktop machines are almost as common as telephones.

“You saw it piecemeal before,” said industry consultant Sam Albert. The new machines show that IBM intends the mainframe to be the “traffic cop” of computer networks, said Albert, a former IBM executive.

In addition to annoucing 18 new machines, IBM said it would provide systems that will allow mainframes to manage information on all sorts of computers throughout a company.

Such systems would address the growing concern of companies that too much information is spread among desktop computers that don’t communicate well with each other.

The company said it also will provide products that will make it easier to connect non-IBM computers to a network of IBM machines.