Removing freight rail trains from the Minneapolis Kenilworth corridor to make way for southwest light rail would require the construction of a rail interchange in St. Louis Park that could cost as much as $70 million.

The estimate -- from Dave Christianson, manager of freight planning for the Minnesota Department of Transportation -- highlights the expense and complexity of the proposed rerouting of freight rail for light rail.

Currently just four freight trains a day -- two each way -- travel the Twin Cities and Western Railroad (TC&W) through Kenilworth to Minneapolis. Rerouting them to the Northfield and Southern Railway (MN&S), which currently carries two trains a day north-south through St. Louis Park, would require an expensive new connection between the two lines.

Christianson, in a meeting Jan. 20 in Edina, estimated the cost of that connection at between $50 million and $70 million.

The high price reflects that the two rail lines are separated by 30 feet of elevation, Christianson said. A connection would have to take tracks up an embankment supported by retaining walls. Trains would climb the grade while making a 90-degree turn from one rail line to the other, Christianson said.

Now the two rail lines are joined by a low-grade switching track that requires trains to stop and break apart, moving five cars at a time to the next track. "A true interchange track would allow uninterrupted movement without breaking the train from one line to another," Christianson said.

The new connection is under study because the Kenilworth corridor is part of the route selected for the proposed southwest light-rail line between Minneapolis and Eden Prairie.

Hennepin County, which owns the Kenilworth corridor, says pinch points along the route -- between Cedar Lake and Lake of the Isles -- do not leave space for both freight and light rail. The county has planned the light-rail line assuming the freight tracks would be moved.

A 2009 study of six alternative routes for the freight said the St. Louis Park route made the most sense and a recent review of the options found no obvious alternative. The city of St. Louis Park has challenged the assumption that the trains must be moved. A final decision about the rerouting is expected later this year.

Those who live nearest the line in St. Louis Park are waiting for the results of a $200,000 study by a county consultant, Kimley-Horn and Associates, about what safety mitigation measures the community could expect if the trains were rerouted to St. Louis Park.

The consultants will present new information about noise and vibration at a meeting at 7 p.m. on Feb. 24 in St. Louis Park City Hall.

Kimley-Horn is expected to make its own estimate of the cost of building a new connection between the rail lines in St. Louis Park. The firm expects to wrap up its study sometime in May.

Christianson referred to the $70 million estimate in a freight rail presentation to the Edina transportation commission.

Safety in the Park, a residents advocacy group opposed to more freight trains through St. Louis Park, says the high rerouting cost argues for keeping them in the Kenilworth corridor. "It's an enormous waste of taxpayer dollars," said Thom Miller of Safety in the Park.

Safety in the Park suspects that rerouting the Kenilworth tracks and putting in a new connection is part of a larger freight-rail upgrade that could attract more trains than the community is being told about.

If it's best for the state to improve the freight corridor residents would accept that, if homes close to the tracks are purchased and new safety measures are put in at crossings and at St. Louis Park High School, Miller said.

Christianson said that if a new interchange were built in St. Louis Park it would be to maintain the connections the Kenilworth corridor now provides - not to promote expanded use of the track which would in any case be a private decision of the railroads.

The TC&W, which serves businesses and communities through western Minnesota, has one route to the metro area and that is through Kenilworth.

If Kenilworth is closed to freight, the trains must be accommodated elsewhere, Christianson said. "It's a part of the rail network that we can't just shut down," he said. "There has to be some way for TCW to take all of their freight traffic from western Minnesota and connect with the outside world."

Laurie Blake • 612-673-1711