Obama sees challenges ahead

By Caren Bohan

BALTIMORE (Reuters) - Barack Obama warned Americans on Saturday of the vast challenges ahead as he rolled by train towards Washington, kicking off three days of celebration of his inauguration as the 44th president of the United States.

Obama waved to crowds from the back of a vintage train car and stopped twice for rallies in frigid weather on the journey from Philadelphia to Washington, where he takes office on Tuesday amid the deepest economic crisis in generations and wars in Iraq and Afghanistan.

"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, evoking the patriots who launched the American fight for independence in the city in 1776.

"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."

He stressed in Philadelphia and at later stops in Wilmington, Delaware, where he was joined by Vice President-elect Joe Biden, and Baltimore that it will take time and sacrifice to turn the economy around.

"Such enormous challenges will not be solved quickly. There will be false starts and setbacks, frustrations and disappointments," Obama told about 40,000 cheering supporters who greeted him in Baltimore.

"We will be called to show patience even as we act with fierce urgency," he said.

Obama, a Democrat, has vowed to spend hundreds of billions of dollars to jolt the country out of a deepening recession.