// MODEL
public class Chapter
{
    public int SysId { get; set; }
    public string Caption { get; set; }
    public IEnumerable<Position> Position { get; set; } 
}
public class Position
{
    public int SysId { get; set; }
    public string Caption { get; set; }
    public Tzm Tzm { get; set; }
    public IEnumerable<Mch> Mch { get; set; }  
}
[XmlRoot("Tzm")]
public class Tzm
{
    [XmlAttribute("Code")]
    public int Code { get; set; }
    [XmlAttribute("Caption")]
    public string Caption { get; set; }
}
public class Mch
{
    public string Code { get; set; }
    public string Caption { get; set; }
}