获取所有活动的运输方法，循环每个方法，看看它是否与您想要的匹配

$activeCarriers = Mage::getModel('shipping/config')->getActiveCarriers();
foreach($activeCarriers as $code => $method) {
    if($code == 'yourcode') {
         $result = Mage::getModel('shipping/rate_result');
    }

}