please try to use the code below, the ParseXML/XMLFile.xml is the file where ive pasted the content of your xml:

XDocument doc = XDocument.Load(Server.MapPath("~/ParseXML/XMLFile.xml"));
        List<SRADBData> objList = new List<SRADBData>();
        var listMain = doc.Elements("TRR").Elements("Detail");
        foreach (XElement xll in listMain)
        {
            if (string.Compare(xll.Name.ToString(), "Detail", true) == 0)
            {
                SRADBData objSRA = new SRADBData();
                Segment objSeg = new Segment();
                if (xll.Elements("Segment") != null)
                {
                    objSeg.orgin = xll.Element("Segment").Element("Orgin").Value.ToString();
                    objSeg.segmentId = Convert.ToInt32(xll.Element("Segment").Element("SegmentId").Value);
                }
                objSRA.originProduct = xll.Element("OriginProduct").Value.ToString();
                objSRA.routeId = Convert.ToInt32(xll.Element("RouteId").Value);
                objSRA.toDate = Convert.ToDateTime(xll.Element("ToDate").Value);
                objSRA.segment = objSeg;
                objList.Add(objSRA);
            }
        }

but before using it make sure you've used these namespaces:

using System.Linq;
using System.Xml.Linq;