A $100 million typo in a report about where noisy freight traffic will go left Hennepin County officials dismayed Tuesday and St. Louis Park officials crying foul.

"The fact they made a $100 million error makes me wonder what other errors are in the report," said Sue Sanger, a City Council member whose ward is slated to get the traffic if Minneapolis doesn't. "I was shocked."

Right now freight trains go through south Minneapolis next to a bike trail. At issue is whether to relocate those freight trains to St. Louis Park to make room for the proposed Southwest Light Rail line or keep the freight trains in Minneapolis, next to the light rail.

Some St. Louis Park residents have long argued that keeping freight trains in Minneapolis would be $123 million cheaper than redirecting them to St. Louis Park. But their argument has lost some steam after the county's consultants discovered the typo that underestimated the cost of keeping freight trains in Minneapolis by $100 million.

That narrows the difference between the two plans to $23 million.

"We can't understand essentially how a $100 million typo can occur 45 days after the report is released," said Thom Miller, co-chair of a grass-roots neighborhood group that is against the reroute.

They're now pushing the Federal Transit Administration (FTA) to conduct an independent review. They say that, even if the cost difference is less, they'll still have increased noise, train vibrations and risk of derailments along with falling property tax values.

"Our primary concern is the same," Miller said, adding that the train corridor through his neighborhood "was not built to handle heavy freight trains."

Conclusion unchanged

County Commissioner Gail Dorman, who represents both St. Louis Park and the Kenwood neighborhood in Minneapolis, which supports the reroute, said she was dismayed by the error in the report, "but somehow it was overlooked."

The error doesn't change the conclusion of the more than 3,000-page document, which recommends rerouting freight trains to St. Louis Park.

If approved, construction of the project would start in 2015.

On Tuesday, county commissioners were privately embarrassed but glad the mistake in the draft report was caught now rather than later.

"It's kind of incomprehensible to me," Commissioner Peter McLaughlin said. "We're talking to the consultant but we found it and we're moving forward."

Commissioner Jeff Johnson said it was embarrassing for whoever made the mistake.

"It appears to be that somebody screwed up and made a mistake and now we know," Johnson said.

HDR Engineering, an international company based in Omaha, notified St. Louis Park city leaders of the error on Monday -- 45 days after the consultant released the draft environmental impact statement. The document details the possible consequences the 15-mile line could have on the five cities it would go through -- Minneapolis, St. Louis Park, Hopkins, Minnetonka and Eden Prairie.

In a letter dated Nov. 21, HDR Engineering says editing and formatting of the document in response to FTA comments caused the error.

'A mess on our hands'

St. Louis Park residents in the group, Safety in the Park, are skeptical, accusing Hennepin County of making the report more favorable to the county, which has supported rerouting freight trains. The error, Miller said, should have been caught much earlier.

"From a public process, we've really got a mess on our hands," he said.

The county has already held two of three public hearings on the draft report, in Minneapolis and St. Louis Park earlier this month. The final public hearing is Thursday at Eden Prairie City Hall. The county will continue to accept input until Dec. 11 before forwarding the feedback to the Metropolitan Council to review.

The Met Council, which will determine whether to reroute freight trains or not, will release a final environmental impact statement that will give more detailed effects on cities and specific solutions to issues.

St. Louis Park Mayor Jeff Jacobs said Tuesday he was relieved the error was caught now. "It certainly changes the nature of the discussion. [But] at some point the decision is going to be made. We'd better be ready for it either way."

Staff writer Rochelle Olson contributed to this report.

Kelly Smith • 612-673-4141; Twitter: @kellystrib