NEW YORK – At least three of the nation's largest railroads said Thursday they will redirect traffic out of New Orleans ahead of Tropical Storm Gustav.

Union Pacific, the nation's largest railroad, is shifting traffic that went through New Orleans to Memphis, Tenn. and St. Louis, according to spokeswoman Raquel Espinoza.

Espinoza said the Omaha, Neb.-based company has received word that the floodgates in New Orleans may close on Saturday, which would prevent any rail traffic from moving into or out of the city. Floodgates are used to control the flow in reservoir, river, stream and levee systems.

Union Pacific employees are also moving equipment out of low-lying areas.

Fort Worth, Texas-based Burlington Northern Santa Fe Corp. will close its facility in New Orleans at noon central time on Friday in preparation for the storm.

The intermodal facility, BNSF's only location in New Orleans, normally runs 24 hours a day. Trains heading to the facility will be held until clearance is given to re-enter the area, according to spokesman Joe Faust.

Burlington Northern has 20 employees in New Orleans and four trains coming in and out of the city each week, Faust said.

Another railroad, Norfolk Southern Corp., has halted train traffic south of Hattiesburg, Miss., including New Orleans, effective immediately. According to the Norfolk, Va.-based company's Web site, traffic moving to and from connecting carriers is also suspended. A Norfolk Southern spokesman did not return an e-mail request seeking further comment.

The number of employees that work at the New Orleans facilities of Norfolk Southern and Union Pacific, as well as the number of trains that travel to the facilities each day, was not immediately available.

A spokesman CSX Corp., which also run trains through New Orleans, did not return an e-mail seeking comment.

On Thursday afternoon forecasters said Tropical Storm Gustav was near the eastern tip of Jamaica with sustained winds around 70 miles per hour. It is expected to strengthen to hurricane force as it heads into the Gulf of Mexico. It could make landfall on the US Gulf Coast by Tuesday.