"When Washington puts economic policies to work for Wall Street, but not Main Street, factories close their doors, workers lose their jobs, and families lose their homes," presumptive Democratic presidential candidate Barack Obama told the U.S. Conference of Mayors.

As Obama continues to define himself as the candidate for working families, he lashed out at big oil and gas companies, observing that high energy costs are pinching municipal budgets, forcing school districts to cut back on spending for textbooks and teachers as they struggle to buy the gasoline and diesel fuel to operate school- and transit buses.

Obama contrasted his positions, in support of increased public transit, relief for struggling homeowners and creation of a trust-fund to increase home ownership, with the policies of Sen. John McCain, who is "calling for nearly $2 trillion in tax breaks for big corporations and the wealthiest Americans," but is opposed to programs that revitalize communities.

"The stakes could not be higher," Obama said. "Our children will grow up competing with children in Beijing and Bangalore and Berlin. And make no mistake -- their governments are doing everything they can to give their countries an edge by investing in regional growth.

"China is developing an advanced network of ports and freight hubs," Obama said, while "Germany has launched rail projects to bind its major metro areas more closely together. To compete and win in our global economy, we have to show the same kind of leadership."

Obama pledged programs to create new jobs and higher wages, beginning with infrastructure repair. "We’re spending less on our infrastructure than at any time in the modern era," he said.

"Just the other day, Sen. McCain traveled to Iowa to express his sympathies for the victims of the recent flooding," Obama said. "I’m sure they appreciated the sentiment, but they probably would have appreciated it more if he hadn’t voted against funding for levees and flood control programs, which he seems to consider pork."

Obama proposes a National Infrastructure Reinvestment Bank that will invest $60 billion over 10 years to create nearly two million new jobs.

"Instead of building bridges to nowhere, let’s build communities that meet the needs and reflect the dreams of our families," Obama said.

"Let’s invest that money in a world-class transit system," Obama said. "Let’s re-commit federal dollars to strengthen mass transit and reform our tax code to give folks a reason to take the bus instead of driving to work -- because investing in mass transit helps make metro areas more livable and can help our regional economies grow.

"And we’ll also invest in our ports, roads, and high-speed rails, because I don’t want to see the fastest train in the world built halfway around the world in Shanghai. I want to see it built right here in the United States of America."

Among policies promised by Obama is to pursue a tax cut of up to $1,000 for working families and repeal of oil and gas industry tax breaks.