The three-day ceremonial farewell that Washington is hosting this week for the late Ronald Reagan will include a 34-hour period for public viewing of the former president's coffin, bring at least 20 foreign heads of state to the capital and likely cause major traffic tie-ups in parts of the region, officials said yesterday.

In addition to current political leaders, the list of dignitaries expected at Friday's funeral at Washington National Cathedral includes former Soviet leader Mikhail Gorbachev, former British prime minister Margaret Thatcher and former Japanese prime minister Yasuhiro Nakasone.

Hundreds of officials and volunteers were focused yesterday on the logistics of the city's first presidential funeral in 31 years, from the protocol for seating heads of state inside the cathedral to plans to provide water and medical assistance to those waiting outside the U.S. Capitol to view Reagan's coffin.

The casket will be flown from California to Andrews Air Force Base tomorrow aboard one of the Boeing 747s used as Air Force One, White House press secretary Scott McClellan said. It will arrive at Andrews about 5 p.m. and reach the Capitol by 7 p.m., officials said.

Vice President Cheney will speak at a welcoming ceremony in the Capitol Rotunda and participate in a wreath-laying, according to White House officials. The event will include Reagan family members, congressional leaders and some foreign heads of state.

Capitol Police Chief Terrance W. Gainer said public viewing of the coffin will begin about 9 p.m. tomorrow and continue, without interruption, until about 7 a.m. Friday. He said the public can begin lining up at any time at Garfield Circle near First Street and Maryland Avenue SW. Water, portable toilets and medical assistance will be provided near the Capitol Reflecting Pool, he said. Any overflow crowd will be lined up in an area between Third and Seventh streets along the center of the Mall.

The Capitol closed to regular public tours at 4:30 p.m. yesterday, and tours will resume at 9 a.m. Saturday.

At 10:30 a.m. Friday, Reagan's coffin will be transported to the cathedral in Northwest Washington for a funeral service scheduled to begin an hour later. At 2:45 p.m. Friday, it will be flown back from Andrews to Naval Air Station Point Mugu, Calif.

D.C. Police Chief Charles H. Ramsey said that he has canceled days off for all officers from tomorrow through Friday and that officers in the department's special operations division will be working 12-hour shifts.

"This is a huge event for us in the District of Columbia," Ramsey said. "It will require a lot of resources. In a post-9/11 world, we have to be very concerned about the potential that something could happen."

Ramsey urged people who want to view the funeral procession or visit the Capitol to walk or take public transit. Capitol Police have asked Metro to stay open overnight or offer shuttle service from Robert F. Kennedy Memorial Stadium.

Although no details of road closings were announced yesterday, area transportation officials warned drivers to avoid the eastern part of the Capital Beltway tomorrow afternoon because of the 6 p.m. motorcade that will bring Reagan's coffin from Andrews to downtown Washington. They said traffic will also be disrupted around the cathedral, particularly the morning of the funeral.

The cathedral yesterday bore abundant evidence of the preparations for Friday's invitation-only service. Workers set up chain-link security fences along the outside walkways. Temporary exhibits at the back of the church were stored to make more room. And officials from the Secret Service, Capitol Police and the Military District of Washington conferred about security in the bishop's boardroom, now a temporary communications center.

Those invited to the funeral include the nation's four former presidents, the U.S. Supreme Court justices, members of Congress and the diplomatic corps and members of the Joint Chiefs of Staff. Guests will be brought to the church on buses from designated staging areas, according to cathedral spokesman Gregory A. Rixon.

Reagan's funeral will be one of the most significant events held in the majestic house of worship, Rixon said. In terms of size and national importance, he said, it will be on a par with the memorial service for the victims of the September 2001 terrorist attacks, an event that drew 3,700 people.

"This will be a great service, in a great church, for a great man," Rixon said.

He said about 200 cathedral staff members are working on the funeral preparations. Their tasks include ordering flowers, installing additional chairs, preparing the program of service and going over arrangements for emergency medical aid. The cathedral can accommodate up to 4,000 people.

By law, every former president is entitled to a state funeral, and details of such events are described in the military's State Funeral Plan. The document of several hundred pages spells out the movements and placement of family, officials and guests. Most aspects of the funeral will follow military traditions established in the 19th century.

However, the president's family has a great deal of say in how the event proceeds, cathedral officials said.

"It's like any funeral; the family has a great deal of control over who is involved," said Episcopal Bishop of Washington John Bryson Chane, who is also dean of the cathedral. In this case, he added, "the most important thing is to respect the family's desire to keep the service very simple."

The Rev. W. Bruce McPherson, the cathedral's canon for liturgy and worship, said the service, which will last about an hour, is "pretty much the burial rite of the Episcopal Church."

The family also asked that the service have an ecumenical aspect, he said. Faith leaders invited to the ceremony include Roman Catholic Cardinal Theodore E. McCarrick, archbishop of Washington; Archbishop Demetrios, head of the Greek Orthodox Church; Mohammad Magid, imam of the All Dulles Area Muslim Society in Sterling; and Rabbi Harold Kushner, an author of spiritual books.

Former U.S. senator John C. Danforth, who is an Episcopal priest, was selected by the family to lead the service. He will be assisted by Chane and the bishop's vicar, the Rev. Ted Eastman, a retired Episcopal bishop of Maryland.

McPherson said that plans currently call for four tributes to Reagan during the service, including ones by President Bush and former president George H.W. Bush. He declined to identify the other two speakers because their participation has not been confirmed.

Serving as honorary pallbearers, at the request of Reagan's family, will be former presidential aides Michael K. Deaver and Fred J. Ryan; former White House physician John E. Hutton; television personality Merv Griffin; and former U.S. Information Agency head Charles Z. Wick.

Chane said he was told that former president Gerald R. Ford, who is ill, will not attend the funeral service.

Reagan's family drew up the guest list of relatives and personal friends, and the State Department is responsible for issuing invitations to foreign leaders and dignitaries.

Handling the logistics for a state funeral is an enormous task, said Selwa "Lucky" Roosevelt, chief of protocol under Reagan. In addition to meeting foreign dignitaries, State Department officials have to observe protocol in seating at the cathedral.

"Kings and queens take precedence over presidents, then prime ministers," she said. "There is a pecking order."

Within each category, seniority is accorded the longest-serving.

When Theodore Roosevelt went to the funeral of Queen Victoria, for example, he did not sit in the first few rows.

"Here he is, the president of the United States, a very important country, but he was outranked by all sorts of kings and queens," said Roosevelt, who was married to the former president's grandson. "They were marching ahead, and there was Theodore. I know this from family lore."

Staff writers Roxanne Roberts, Lena H. Sun and Mike Allen and staff researcher Bobbye Pratt contributed to this report.

Nathan Grace leads a tour of Washington National Cathedral, which has been open to the public while funeral preparations are made.Displays at the National Cathedral created for tour groups and historic reference are disassembled and stored as crews work to create more space for the funeral service.