Obama arrives in Washington ahead of inauguration

Washington: United States President-Elect Barack Obama arrived in Washington on on Saturday night, amid cheering crowds ringing in three days of celebration ahead of his inauguration on Tuesday.

Rolling into Washington on a vintage train car, Obama waved to crowds as he completed the symbolic 7-hour journey from Philadelphia to Washington.

Obama warned Americans on Saturday of the vast challenges ahead as he takes office as the 44th president of the United States.

"Only a handful of times in our history has a generation been confronted with challenges so vast," Obama said as he began the trip in Philadelphia.

"While our problems may be new, what is required to overcome them is not," Obama said. "What is required is the same perseverance and idealism that our founders displayed."

The 220-km train journey, which retraces the steps of Abraham Lincoln, sends America into three days of festivities to celebrate Obama's swearing in on Tuesday afternoon.

Crowds of several hundred people greeted America's first African-American president as the train pulled in at a few stops along the route.

The train stopped in Delaware to collect Vice President-Elect Joe Biden.

On Sunday, Obama will open a star-studded concert at Washington's Lincoln Memorial. Then he will attend an event honouring Martin Luther King Jr before joining volunteers in the Washington area.