TAMPA, Fla.  President Obama sought to rekindle the fire of his presidential campaign on Thursday as he left behind his political challenges in Washington and began a series of trips around the nation to show that his administration is striving to rebuild the economy and accelerate sluggish job growth.

A day after delivering his State of the Union address, Mr. Obama came to Florida to announce the investment of $8 billion in high-speed rail projects in 13 major corridors, which he said would provide a down payment for the most significant advance in transportation since the Interstate highway system was built more than a half-century ago.

On Friday, the president plans to head to Baltimore where, aides said, he will urge small businesses to increase their hiring with tax credits for new employees. Each of the stops is intended to tie Mr. Obama to programs that may be more popular locally, like a railway from Tampa to Orlando, than the economic stimulus plan has been over all.

“The worst of the storm has passed, but I think all of you understand, the devastation remains,” Mr. Obama told an audience at the University of Tampa. “One in 10 Americans still can’t find work. That’s why creating jobs has to be our No. 1 priority in 2010.”