In his more than 40 years at Glenn O. Hawbaker Inc., a heavy construction contractor, CEO Daniel R. Hawbaker has never seen layoffs like the ones he's made this year. A work force that usually hovers between 1,300 and 1,400 has been slashed by more than 30 percent since October, a sign of the sluggish economic times for the State College firm.

No wonder, then, that Mr. Hawbaker, a Republican, is so gung-ho for President-elect Barack Obama's plan to apply crash paddles to the heart of the American economy by injecting billions into infrastructure improvements. If the Democrat's plans become reality, $175 billion or more might be spent on roads, bridges, transit, schools, water and sewerage, environmental clean-up and the country's electrical grid over the next two years.

The goal of the sprawling plan, outside of the obvious improvement of the U.S. infrastructure, is to put Americans back to work via the biggest public-works spending spree seen since the country's superhighway system was begun in the 1950s. The total proposal might be as large as $700 billion, including direct infrastructure spending as well tax breaks.

Pennsylvania, with its aging infrastructure, figures to get more than a fair slice of the pie. And the companies that stand to benefit most are builders, suppliers, utilities, materials manufacturers and contractors.

"This is long overdue and needed," Mr. Hawbaker said. "These aren't pork-barrel projects, walking paths, duck ponds." Many of Pennsylvania's improvement projects have been on waiting lists for years, awaiting funding. Last week, one of Mr. Hawbaker's design teams was working on an emergency bridge repair job -- one of more than 5,000 "structurally deficient" bridges in the state.

"Pennsylvania could really benefit from a lot of these projects," he said.

The companies that supply raw materials to the contractors also are hoping that the public works investment will help soften the effects of the recession over the next 12-24 months.

"I think that most of our customers are fearful of the economy of the next year or two," said Sam Miller, vice president of sales and marketing at Trumbull Industries in Warren, Ohio.

"Public-type construction projects can certainly have the effect of bolstering the local economy. I can't imagine any of our contractors not looking forward to an injection of capital into the construction sector."

Wall Street has greeted the infrastructure plan with cautious enthusiasm. On Nov. 20, the Dow Jones U.S. Heavy Construction index price was at 178.95. Two days later, Mr. Obama outlined his public works plan, and as of Friday the index closed at 298.06, an increase of 66 percent in less than a month (but still below the 52-week high of 727.56).

But those who hope the rising tide will lift all boats could be disappointed. Contractors and steel producers may get a boost, but heavy equipment suppliers -- the companies that make bulldozers, steamrollers and excavators -- might not, since the gains from the public works spending will likely be offset by sliding reorders from commodities companies and residential builders. A company that in another year might have bought new machinery may instead decide to defer purchases, hoping to squeeze some extra months out of what they already own, in an effort to save capital.

"You can't just turn this stuff on," said Alexander Blanton, a Caterpillar analyst for New York's Ingalls & Snyder LLC. "I know Obama talks about shovel-ready projects. But it's still a process. ... This all takes a lot of time."

Caterpillar, the largest producer of construction and mining equipment by far, should expect a flat 2009, Mr. Blanton said -- Mr. Obama's public works plan should "cushion" Caterpillar's stock price next year, but it won't create a sudden bounty of orders.

That doesn't mean the public works plan isn't a smart investment, Mr. Blanton said.

"It's an investment in the future. You need to do it anyway," he said. "Infrastructure spending has been a time-honored way to boost the economy during a recession and put people back to work [since] the Egyptians began building pyramids in 2700 B.C."

Cement and steel are one component of Mr. Obama's public works plan. Another is digital -- improving the electric grid, wiring the country for high-speed Internet, even computerizing medical records.

"As a general rule, we think any improvement in the [electricity] infrastructure is a positive for the region," said Joe Vallarian, spokesman for Downtown-based Duquesne Light. The company is nearing the end of a three-year, $500 million improvement to its transmission and distribution infrastructure, but work remains.