The U.S. freight railroad industry is finding itself in the role of apprehensive party host amid excitement surrounding the government-led push for high-speed passenger services.

Top railroads, such as Union Pacific Corp. (UNP) and CSX Corp. (CSX), own the tracks and rail corridors where much of the Obama administration's $8 billion in stimulus money to jump-start high-speed passenger service ultimately will be spent.

Many of the freight carriers are wary that their recent network efficiency gains - including substantially reduced train dwell times and improved on-time arrivals - could be jeopardized. They're also worried that more and faster passenger traffic will drain future freight capacity and raise safety issues.

"We do have very serious concerns" about safety in certain stretches, said Louis Renjel, CSX vice president for strategic infrastructure. "It's not a question really of anything other than physics" when trains are moving at varying speeds.

But CSX and many of the other freight carriers, which already accommodate trains operated by the National Railroad Passenger Corp., or Amtrak, have expressed broad support for the passenger-push nonetheless, saying greater public awareness of rail's benefits is good for their industry.

Most say they don't expect to oppose any projects, provided they're not expected to foot the bill for upgrades, such as new tracks and sidings, needed to preserve freight capacity and ensure safety.

"All we're saying is that as these higher speeds are contemplated, that the capacity is built to operate them," said Deb Butler, Norfolk Southern Corp.'s (NSC) chief information officer. "We are willing to sit at the table and talk to anyone about passenger rail."

The freight railroad industry is federally regulated and has political incentive to retain good community relations. Many railroads also have long-term agreements in place granting access rights to Amtrak.

Requests for the stimulus money already have far outpaced the $8 billion available, with 40 states and the District of Columbia submitting more than $100 billion in pre-applications.

The final amount of requests will go up or down a bit once the Federal Railroad Administration tallies applications that have been refined and resubmitted. It's unclear when grants will be awarded.

Most Amtrak trains operate at maximum speeds of 79 miles per hour, compared to 50 mph or so for freight trains. The stimulus funding likely will result in passenger service of up to 110 mph in some of those corridors.

European-style bullet trains - which zoom by at upwards of 200 mph - would require separate, sealed-off corridors, and are decades away in the U.S.

Still, the potential for conflict clearly exists even with the slower-speed U.S. plans. CSX's Renjel contended that speeds faster than about 90 mph are "completely incompatible" on some congested freight routes, but proponents of at least two high-profile projects in busy CSX corridors envision exceeding the limit.

Backers of both those projects - linking Cleveland, Columbus and Cincinnati in Ohio, and between Albany and Buffalo in New York - are aware of the railroad's concerns and said their projects are still in early planning stages.

"We're cognizant of the importance to CSX" of the Albany-to-Buffalo corridor, said Stanley Gee, acting commissioner of New York's transportation department.

"It's too early to say whether or not we will build a totally separate track or corridor from what is owned by CSX," Gee said. "We have a goal [of high-speed rail] in mind. What we haven't looked at is what is the infrastructure needed to get us there, and is it cost effective."

Union Pacific is engaged in a similar exercise with Illinois officials, who want 110-mph passenger service on a UP corridor linking Chicago and St. Louis. Union Pacific has little choice in the matter because it agreed more than a decade ago to allow 110-mph service on the route.

"We're confident it can be done safely," Union Pacific spokesman Bob Turner said, although he added that it will result in a large and complex corridor with dozens of sidings and crossovers.

Union Pacific won't be paying for the passenger-related upgrades, but Turner made clear that the railroad has little to gain from them either.

"We don't benefit from adding that complexity to our system," he said. "There is no economic incentive to it, that's for sure."

-By Bob Sechler, Dow Jones Newswires; 512-394-0285; bob.sechler@dowjones.com