(AP) - Sen. Edward Kennedy was there for his constituents for nearly five decades, and on Friday they were repaying that loyalty by the tens of thousands.

For the second day, thousands of mourners lined up to pay their final respects to Kennedy as his body was in repose at the John F. Kennedy Library and Museum.

A private memorial for family and invited friends will be held at the library Friday evening. U.S. Vice President Joe Biden as well as Sens. John McCain, Orrin Hatch and Christopher Dodd are expected to speak.

A funeral Mass is scheduled for Our Lady of Perpetual Help Basilica in Boston on Saturday. President Barack Obama is expected to deliver the eulogy.

Many of the people who took time out to pay their respects to Kennedy on Thursday said they did so because he had made time for them at some point during his 47 years in office.

As mourners stood in line for as long as 2 1/2 hours, members of the Kennedy family, including some grandchildren, came out and thanked them for coming.

Members of the Kennedy family, including his daughter Kara Kennedy Allen, nephew Tim Shriver and 81-year-old Jean Kennedy Smith, the senator's sister and the last surviving Kennedy sibling, greeted visitors.

More than 21,000 people filed past Kennedy's flag-draped casket Thursday in a high-ceilinged room with spectacular views of Boston Harbor. A five-person military honor guard stood at attention around the casket.

The public event followed a private Mass on Thursday at the family compound in Hyannis Port, where the senator died of brain cancer this week at age 77. The family watched as the casket was loaded into a hearse for the journey to Boston.

The late senator's loved ones - including niece Caroline, daughter of former President John F. Kennedy, and son Patrick, a Rhode Island congressman - joined in the private Mass.

All the living presidents had been expected to attend the funeral, but former President George H.W. Bush said Friday his son, former President George W. Bush, would represent the Bush family.

Kennedy will be buried Saturday evening near his brothers John and Robert at Arlington National Cemetery in northern Virginia.