WASHINGTON (AP) — Invoking hope and history, President-elect Barack Obama rolled into the capital city Saturday night pledging to help bring the nation "a new Declaration of Independence" and promising to rise to the stern challenges of the times. He kicked off a four-day inaugural celebration with a daylong rail trip, retracing the path Abraham Lincoln took in 1861.

Obama began his day in Philadelphia, where he said the young nation had faced its "first true test" as a fragile democracy. He ended it in Washington, where his own tests await after his inauguration on Tuesday.

The president-in-waiting drew on a grand heritage of American giants as he appealed "not to our easy instincts but to our better angels," an echo of Lincoln's first inaugural address. He took note of the enormous challenges that lie ahead and promised to act with "fierce urgency," a phrase often used by the Rev. Martin Luther King Jr.

Riding a vintage railcar on his whistle-stop trip to Washington, Obama carried with him the hopes of a nation weary of war, frightened of economic chaos and searching for better days. Vice President-elect Joe Biden joined the journey en route, from his home in Delaware, and spoke for many when he said he was excited and ready for Tuesday.

Then, sobered by the challenges of governing, Biden added: "I think it's Wednesday we need to be ready."

Obama was smiling and confident throughout the day and across the miles, reaching at each stop for history's lessons. In Philadelphia, he noted the risks taken by the men who declared America independent from Britain. In Wilmington, he applauded the state that first ratified the Constitution. And in Baltimore, he hailed the troops at Fort McHenry who beat back the British navy and inspired the poem that became "The Star-Spangled Banner."

Washington pulsed with anticipation of Obama's swearing in as the nation's first black president. The city was aflutter with preparations for four days of parties and pomp, shadowed at every turn by layer upon layer of security. For every banner or piece of bunting that was going up around the city, there was a concrete barrier or metal fence at the ready as well.

Revelers eager to get a head start on the celebration already were flowing into the city.

Toni Mateo, 38, arrived on a packed train from Atlanta. It was a quiet ride at first, he said.

"I just screamed out 'Obama,' and the whole crowd erupted," he said.

For all the travelers arriving in Washington, there were plenty headed the opposite direction — fleeing the crowds, the security, and the winter cold.

For traveler Obama, there was a celebratory air as his train pulled out of the station at Philadelphia.

"Welcome aboard the 2009 inaugural train to D.C," the conductor intoned.

Obama's blue rail car was tacked onto the back of a 10-car Amtrak train filled with hundreds of guests, reporters and staff for the 137-mile ride to Washington. Along the way, Obama and his wife, Michelle, appeared on the back balcony periodically to wave to shivering crowds bundled up in blankets and parkas who had gathered by the dozens, the hundreds and more along the route.

One held a sign that read, "Happy Birthday Michelle," taking note of the future first lady's 45th birthday. Another, in Delaware, waved a placard that said, "We came from Massachusetts 2 C U."