The potential benefits of upgrading rail lines in the Interstate 81 corridor are understated in an environmental analysis of traffic and freight on the highway, a rail advocacy group says.

The analysis, called a draft environmental impact statement, was made public in November. It proposes $500 million of spot upgrades to railroad tracks in Virginia, but they are "too weak to do any good," the advocacy group Rail Solution said.

For rail upgrades to be effective in switching freight from trucks to trains, the improvements must be applied to almost 600 miles of track in five states, from Knoxville, Tenn., to Harrisburg, Pa., the group said Wednesday.

The analysis, done mostly by a consultant and announced by the Virginia Department of Transportation, limits the upgrade proposals to a 325-mile corridor in Virginia.

"We tried to prevent them setting up rail to fail by suggesting ... that the DEIS look at almost 600 miles of the I-81 corridor," said David Foster of Salem, executive director of Rail Solution. That 600-mile concept is mentioned in the environmental document, but "it's there in words only and the analysis is strictly limited to Virginia," Foster said.

That one-state limitation was chosen by the Federal Highway Administration, said Laura Bullock, a spokeswoman for the Virginia Department of Transportation. VDOT had the report done for the federal agency and "it ultimately belongs to them. They said it is a Virginia-only study," Bullock said.

At the Virginia Department of Rail and Public Transportation, Foster's argument got some support. George Conner of VDRPT said a $500 million upgrade within Virginia would provide a temporary lessening of truck traffic on I-81. But over time, Conner said, that benefit would disappear because the added rail capacity would max out.

Truck traffic then would start to build again on I-81, he said.

But if rail lines are improved throughout the corridor from Knoxville to Harrisburg, Conner said, the amount of freight diverted from highway to rail would increase substantially.

Although VDOT has held discussions with officials of the other four states in the corridor, each state is pursuing its plans for I-81 independently. Tennessee considers rail a key element, along with highways, in its freight movement system. West Virginia, on the other hand, doesn't allow public funds to be used for rail lines.

Bullock declined to comment on the five-state aspect of Rail Solution's criticism, which is being issued during the analysis' public-comment period. "It is a time to gather information. It is not the time to debate anything," Bullock said.

Norfolk Southern Railway, whose tracks would benefit from the proposed upgrades, will comment later, said spokesman Robin Chapman.

He referred to an NS report to state officials two years ago, in which the railroad suggested a project with $306 million of publicly assisted improvements to its rail lines in Virginia. It said the project also would need $264 million in track upgrades outside Virginia, and $305 million worth of new freight cars and locomotives.

Bullock said that about 50 people have commented to VDOT by e-mail concerning the analysis, and other comments have come by letter. Many of the comments deal with the analysis' finding that I-81 needs to be widened to three or four lanes in each direction, depending on location and regardless of how many rail improvements are made.

Bullock listed a few of the e-mail comments:

"Much of the scenic beauty and surrounding ecosystems and communities would be negatively impacted if I-81 were widened. I encourage VDOT to pursue alternatives OTHER than widening I-81," one person wrote.

Another said, "I think that a truck lane on I-81 would help with the flow of traffic. I believe that it will help prevent car and truck collisions in areas were there are a lot of collisions."

A third person wrote, "There is a better way to solve the truck traffic problem, and that is to use the rail system to carry the long-distance freight through this area and use trucks only for short hauls to supplement the rail system."

A fourth addressed the debate on using public funds to benefit a privately owned corporation. "People understand that rail is a critical component of Virginia transportation and now, more than ever, must be subsidized on the same level as highways," that person said.

Foster, of Rail Solution, said the analysis advanced a rail-upgrade concept that would fix up 13 short segments of rail lines in Virginia.

"With these few contemplated improvements, six additional trains per day in each direction could be handled, with an average train speed of 33 mph. Projections of truck diversions [to rail] are virtually useless and self-defeating if based on such meager rail enhancement," Foster said.

"To divert meaningful volumes of through-trucks from I-81 in Virginia, the upgraded rail line would need to handle six new trains per hour, not per day," Foster said.

The analysis said the cost of the five-state upgrade proposed by Rail Solution would be $3.7 billion.

Foster also criticized the analysis' technical aspects, calling them "riddled with inaccuracies and inadequacies."

Many of the technical conclusions are "simply adopted from earlier studies or other informed sources without attempts at independent validation, confirmation or relevance to the environmental assessment," Foster said.