The Chisholm Trail Jeep Club gassed up and went to work Monday on Spur 408 southwest of Dallas. Jeeps strapped themselves together in a train, then pulled in unison to rescue big rigs. "The highway was shut down. There's no wreckers here to help out. We got a bunch of guys together and we freed the highway. That's a pretty good accomplishment," said Jason Gardner of Arlington. The group pulled out at least five tractor-trailers. Monday proved a tough lesson for a lot of drivers. Winter weather is unforgiving. And even if it doesn't look that bad, frozen roads aren't always easy to see. Many downtown streets were dry Monday evening, and so was a large stretch of North Central Expressway from downtown to NorthPark Center.