Mr Bush, who served as the 41st United States president between 1989 and 1993, died late on Friday at the age of 94.
The former president's remains will be flown to Washington, D.C. on Monday following a departure ceremony in Houston, Texas.
"He kept us flying high and challenged us to fly higher still, and he did it with modesty and kindness that would've been surprising in someone one-tenth as tough and accomplished as he was", McConnell said. Bush was the nation's 41st president, hence the locomotive bears the number 4141.
"But now I think we can see in retrospect that he was actually quite successful", Sabato added, particularly in foreign affairs, as he helped shape the Western response to the demise of the Soviet Union and the reunification of Germany.
Former President George W. Bush, the eldest of the four Bush sons, and his wife, Laura, along with brother Neil Bush and his family, boarded the plane for the cross-country trip to Joint Base Andrews outside Washington.
Moreover, Sabato told VOA Bush benefits from a comparison with Trump's demeanor almost halfway through the current president's first term in the White House. At the funeral for his wife, Barbara Bush, who passed eight months ago, Bush paid homage to his wife's favorite cause, literacy, by wearing socks decorated with stacks of colorful books.
The funeral train will include UP No. 4141 George Bush Locomotive, which was unveiled October 18, 2005, during a ceremony near the library and museum on the Texas A&M University campus. "Thank you for your service, Mr. President".
Trump has ordered the federal government to close on Wednesday and both the New York Stock Exchange and Nasdaq will be closed in observance.
"The president and first lady were notified late last night of President George H.W. Bush's passing", Sanders said in the Saturday statement.
President Donald Trump has expressed willingness to extend funding for an additional two weeks, holding off what is expected to be a bitter partisan fight. A state funeral is being arranged with all of the accompanying support and honors.
Once Bush lies in state, his casket will be transported by motorcade on Wednesday morning to the National Cathedral, where a state funeral will be held.