President Bush has chosen a new treasury secretary, part of a shake-up of his economic team. He has asked the head of one of the nation's largest railroad companies to take the job.

The president's choice is John Snow, the chairman of CSX Corporation, a transportation conglomerate based in Virginia.

He is well known in Washington, particularly on Capitol Hill. President Bush says he will be both a key advisor on the economy and a key advocate for the administration's economic policies. "John Snow has excelled as a business leader, an expert on economic policy, an academic and as a public servant," said the president. "He will be a superb member of my Cabinet."

Mr. Snow will replace Paul O'Neill, who resigned under pressure last Friday. The railroad executive, who is expected to be quickly confirmed by Congress, moves into the spotlight at a crucial time.

The president has often said that, while the overall economic indicators are good, the pace of the recovery is far too slow. As he announced the Snow nomination, Mr. Bush said he will be making new proposals to Congress to give the recovery a boost. He said changes are needed to curb unemployment, spur investment, and ease the tax burden on Americans.

"I will be proposing specific steps to increase the momentum of our economic recovery," said President Bush, "and the treasury secretary will be at the center of this effort."

This will be a return to public service for John Snow, who was a Transportation Department official in the 1970's. At 63 years of age, he has decades of experience in business and related fields. But most important to the White House may be his proven ability to work with members of the legislature, and sell the president's economic policies.

In brief remarks, John Snow said he was "humbled and honored" and ready to go to work. "I pledge to you to use all my talents, my power, my energy and my ability to strengthen the current economic recovery," he said.

President Bush must still name a replacement for his White House economic policy advisor Lawrence Lindsey, who also abruptly resigned last week. The leading candidate for the job is believed to be Steven Friedman, former chairman of the Goldman Sachs investment firm.

A number of senior Treasury Department officials are also expected to be pushed out, as part of the shake-up of the Bush economic team. It is the biggest change to date in the upper tiers of the administration, and reflects an acknowledgment in the White House that, while the president's popularity is high, a weak economy could erode public support. Such a scenario played out in 1992, when his father lost a re-election bid, due in large part to economic concerns.