Among the mourners, there was an incredibly moving moment when Bob Dole was helped to his feet to stand before Bush's casket.
Bush's service dog Sully visited the president's casket in the Capitol Rotunda alongside people in wheelchairs who benefited from the Americans With Disabilities Act that Bush signed in 1990.
With Bush's casket atop the Lincoln Catafalque, first used for Abraham Lincoln's 1865 funeral, dignitaries came forward to honor the Texan whose efforts for his country extended three quarters of a century from World War II through his final years as an advocate for volunteerism and relief for people displaced by natural disaster.
Thousands of people have already streamed through the U.S. Capitol building, wishing to pay their respects to Bush, with more lined up to say a formal farewell.
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National Day of Mourning
Bush is lying in state in the rotunda of the U.S. Capitol until 8:45 a.m. EST Wednesday. His casket will be transported by motorcade Wednesday morning to the National Cathedral, where a state funeral will be held at 11 a.m. EST. President Donald Trump, who ordered federal offices closed on Wednesday for a national day of mourning, is to attend with first lady Melania Trump.
Following the service at the National Cathedral, Bush will be flown to Houston on Wednesday with a scheduled arrival of around 4:30 p.m. CST. His body will be transported by motorcade to St. Martin's Episcopal Church, where he and his wife regularly worshipped. A public viewing of Bush's casket will be held at the church from 6:45 p.m. CST on Wednesday until 6 a.m. CST on Thursday.
On Thursday, a private funeral service with about 1,200 invited guests will be held at the church starting at 10 a.m. CST. After the hour-long service, a motorcade will transport Bush's casket to a train station north of Houston, near the international airport named after Bush.
A ceremony will be held at the train station as Bush's casket is loaded onto a Union Pacific train. The train will take about 2 hours to travel roughly 70 miles (113 kilometers) to the city of College Station, home to Bush's presidential library at Texas A&M University.
The locomotive has been painted the colors of the Air Force One plane used during Bush's presidency and bears the number "4141" in honor of the 41st president. The casket will be in a car with Plexiglas windows to allow people to see it during the trip, according to McGrath, the family spokesman.
HOW TO WATCH: Where to watch Pres. George H.W. Bush's procession
After the funeral on Thursday, President George H.W. Bush will take one final ride to College Station to his final resting place.— ABC13 Houston (@abc13houston) December 3, 2018
These are some of the best intersections along the route to see the Bush 4141 train: https://t.co/dqGlgRCDGT pic.twitter.com/WiRPGQbEiC
Burial in College Station
The train is scheduled to arrive in College Station on Thursday around 3:45 p.m. CST. Bush's casket will then be transported by motorcade to the presidential library, where he will be buried at the gated family plot near his wife and their daughter Robin, who died of leukemia at age 3. Barbara Bush died on April 17 at their Houston home. The couple was married for 73 years , longer than any other U.S. presidential couple.
Ceremonies at the presidential library will include a missing man formation flyover. The casket will then be rolled along a path through woods, over a bridge and over a creek for burial during a private graveside service with Bush's family.
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The Associated Press contributed to this report.