Which one is erroneous? Schema file or Xml file

Question

Here is my schema and xml file contents.
When I want to validate my xml file with my schema file I got the error:Element X1 is not defined in this scope. Error line: 25 Error column: 12.
Where is the problem?

<xs:complexType name="LabelType">
    <xs:sequence>
        <xs:element name="Text" type="xs:string"/>
        <xs:element name="X" type="xs:short"/>
        <xs:element name="Y" type="xs:short"/>
        <xs:element name="RotateAngle" type="xs:short" minOccurs="0"/>
    </xs:sequence>
</xs:complexType>

<xs:complexType name="ItemType">
    <xs:choice>
        <xs:element name="Label" type="LabelType" minOccurs="0"></xs:element>
        <xs:element name="X1" type="xs:short" minOccurs="0"></xs:element>
        <xs:element name="Y1" type="xs:short" minOccurs="0"></xs:element>
        <xs:element name="Normal" type="xs:string" minOccurs="0"></xs:element>
        <xs:element name="Reverse" type="xs:string" minOccurs="0"></xs:element>
        <xs:element name="SwitchType" minOccurs="0">
            <xs:simpleType>
                <xs:restriction base="xs:string">
                    <xs:pattern value="MANUEL|AUTO"/>
                </xs:restriction>
            </xs:simpleType>
        </xs:element>
        <xs:element name="X2" type="xs:short" minOccurs="0"></xs:element>
        <xs:element name="Y2" type="xs:short" minOccurs="0"></xs:element>
        <xs:element name="Signalization"  minOccurs="0">
            <xs:simpleType>
                <xs:restriction base="xs:string">
                    <xs:pattern value="YES|NO"/>
                </xs:restriction>
            </xs:simpleType>
        </xs:element>
        <xs:element name="RotateAngle" type="xs:short" minOccurs="0"></xs:element>
        <xs:element name="Width" type="xs:short" minOccurs="0"></xs:element>
        <xs:element name="Height" type="xs:short" minOccurs="0"></xs:element>
        <xs:element name="Source" type="xs:string" minOccurs="0"></xs:element>
        <xs:element name="Item" type="ItemType" minOccurs="0"></xs:element>
    </xs:choice>
    <xs:attribute name="id" type="xs:string" use="required"/>
    <xs:attribute name="type" use="required">
        <xs:simpleType>
            <xs:restriction base="xs:string">
                <xs:enumeration value="SWITCH"/>
                <xs:enumeration value="BLOCKSEGMENT"/>
                <xs:enumeration value="SIGNAL"/>
                <xs:enumeration value="GROUP"/>
                <xs:enumeration value="LEVELCROSSING"/>
                <xs:enumeration value="SIGN"/>
                <xs:enumeration value="TRAINIDBOX"/>
            </xs:restriction>
        </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="ssid" type="xs:string" use="optional"/>
    <xs:attribute name="blockId" type="xs:string" use="optional"/>
</xs:complexType>
<xs:complexType name="IndicatorType">
    <xs:attribute name="id" type="xs:string" use="required"/>
    <xs:attribute name="type" use="required">
        <xs:simpleType>
            <xs:restriction base="xs:string">
                <xs:enumeration value="SWITCHHEATERSSTATE"/>
                <xs:enumeration value="SIGNALSDAYNIGHTMODE"/>
                <xs:enumeration value="POWERSUPPLY"/>
            </xs:restriction>
        </xs:simpleType>
    </xs:attribute>
</xs:complexType>

<xs:element name="FieldVisual">
<xs:complexType>
        <xs:sequence>
            <xs:element name="Region" maxOccurs="unbounded">
                <xs:complexType>
                    <xs:sequence>
                        <xs:element name="Indicators">
                            <xs:complexType>
                                <xs:sequence>
                                    <xs:element name="Indicator" type="IndicatorType" maxOccurs="3"/>
                                </xs:sequence>
                            </xs:complexType>
                        </xs:element>
                        <xs:element name="Track">
                            <xs:complexType>
                                <xs:sequence>
                                    <xs:element name="Item" type="ItemType" maxOccurs="unbounded"></xs:element>
                                </xs:sequence>
                                <xs:attribute name="id" type="xs:string" use="required"/>
                                <xs:attribute name="X" type="xs:integer" use="required"/>
                                <xs:attribute name="Y" type="xs:integer" use="required"/>
                            </xs:complexType>
                        </xs:element>
                    </xs:sequence>
                    <xs:attribute name="id" type="xs:string" use="required"/>
                    <xs:attribute name="name" type="xs:string" use="required"/>
                </xs:complexType>
            </xs:element>
        </xs:sequence>
    </xs:complexType>
</xs:element>

<FieldVisual>
<Region id="MIT" name="TEST">
    <Indicators>
        <Indicator id="MI@MIT" type="SWITCHHEATERSSTATE"/>
        <Indicator id="SGG@MIT" type="SIGNALSDAYNIGHTMODE"/>
        <Indicator id="GK@MIT" type="POWERSUPPLY"/>
    </Indicators>
    <Track id="TEST" X ="632" Y="0">
      <Item id="D@MIT" type="SWITCH">
        <Label>
          <Text>D</Text>
          <X>10</X>
          <Y>30</Y>
        </Label>
        <X1>0</X1>
        <Y1>0</Y1>
        <Normal>US</Normal>
        <Reverse>UU</Reverse>
        <SwitchType>MANUEL</SwitchType>
      </Item>
      <Item id="$CI1@MIT" type="GROUP">
        <Item id="3T.9@MIT" blockId="3T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>0</Y1>
          <X2>60</X2>
          <Y2>-60</Y2>
        </Item>
        <Item id="5S@MIT" type="BLOCKSEGMENT">
          <Label>
            <Text>(5S)</Text>
            <X>110</X>
            <Y>-135</Y>
          </Label>
          <X1>60</X1>
          <Y1>-60</Y1>
          <X2>120</X2>
          <Y2>-120</Y2>
          <Signalization>NO</Signalization>
        </Item>
        <Item id="3T.8@MIT" blockId="3T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>80</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="SGN1@MIT" type="SIGN">
          <X1>90</X1>
          <Y1>-5</Y1>
          <RotateAngle>180</RotateAngle>
        </Item>
      </Item> 
      <Item id="4S@MIT" type="BLOCKSEGMENT">
        <Label>
          <Text>(4S)</Text>
          <X>85</X>
          <Y>-5</Y>
        </Label>
        <X1>0</X1>
        <Y1>15</Y1>
        <X2>180</X2>
        <Y2>15</Y2>
        <Signalization>NO</Signalization>
      </Item>
      <Item id="$CI2@MIT" type="GROUP">
        <Item id="53T.8@MIT" blockId="53T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>80</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="56D@MIT" type="SIGNAL">
          <Label>
            <Text>56D</Text>
            <X>10</X>
            <Y>30</Y>
            <RotateAngle>90</RotateAngle>
          </Label>
          <X1>0</X1>
          <Y1>20</Y1>
          <Width>35</Width>
          <Height>10</Height>
          <Source>sgs3lr</Source>
        </Item>
        <Item id="53T.9@MIT" blockId="53T@MIT" type="BLOCKSEGMENT">
          <X1>80</X1>
          <Y1>0</Y1>
          <X2>20</X2>
          <Y2>-60</Y2>
        </Item>
        <Item id="SGN2@MIT" type="SIGN">
          <X1>5</X1>
          <Y1>-65</Y1>
          <RotateAngle>45</RotateAngle>
        </Item>
        <Item id="6S@MIT" type="BLOCKSEGMENT">
          <Label>
            <Text>(6S)</Text>
            <X>-50</X>
            <Y>-135</Y>
          </Label>
          <X1>20</X1>
          <Y1>-60</Y1>
          <X2>-40</X2>
          <Y2>-120</Y2>
          <Signalization>NO</Signalization>
        </Item>
      </Item>
      <Item id="59@MIT" type="SWITCH">
        <Label>
          <Text>59</Text>
          <X>10</X>
          <Y>30</Y>
        </Label>
        <X1>0</X1>
        <Y1>0</Y1>
        <Normal>SS</Normal>
        <Reverse>US</Reverse>
      </Item>
      <Item id="61@MIT" type="SWITCH">
        <Label>
          <Text>61</Text>
          <X>10</X>
          <Y>30</Y>
        </Label>
        <X1>0</X1>
        <Y1>0</Y1>
        <Normal>SS</Normal>
        <Reverse>SD</Reverse>
      </Item>
      <Item id="$CI17@MIT" type="GROUP">
        <Item id="59T@MIT" type="BLOCKSEGMENT">
          <Label>
            <Text>59T</Text>
            <X>85</X>
            <Y>-5</Y>
          </Label>
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>180</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="56B@MIT" type="SIGNAL">
          <Label>
            <Text>56B</Text>
            <X>155</X>
            <Y>-15</Y>
          </Label>
          <X1>145</X1>
          <Y1>0</Y1>
          <Width>35</Width>
          <Height>10</Height>
          <Source>sgs3rl</Source>
        </Item>
      </Item>
      <Item id="003D@MIT" type="BLOCKSEGMENT">
        <Label>
          <Text>(003D)</Text>
          <X>45</X>
          <Y>-5</Y>
        </Label>
        <X1>0</X1>
        <Y1>15</Y1>
        <X2>100</X2>
        <Y2>15</Y2>
        <Signalization>NO</Signalization>
      </Item>
    </Track>
    <Track id="TEST" X="542" Y="90">
      <Item id="5@MIT" ssid="05@MIT" type="SWITCH">
        <Label>
          <Text>5</Text>
          <X>10</X>
          <Y>30</Y>
        </Label>
        <X1>0</X1>
        <Y1>0</Y1>
        <Normal>UU</Normal>
        <Reverse>US</Reverse>
      </Item>
      <Item id="$CI3@MIT" type="GROUP">
        <Item id ="3T.6@MIT" blockId="3T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>130</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="2BB@MIT" type="SIGNAL">
          <Label>
            <Text>2BB</Text>
            <X>100</X>
            <Y>-15</Y>
          </Label>
          <X1>95</X1>
          <Y1>0</Y1>
          <Width>35</Width>
          <Height>10</Height>
          <Source>sgs3rl</Source>
        </Item>
        <Item id ="3T.7@MIT" blockId="3T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>0</Y1>
          <X2>60</X2>
          <Y2>-60</Y2>
        </Item>
      </Item>
      <Item id="3ST@MIT" type="BLOCKSEGMENT">
        <Label>
          <Text>3ST</Text>
          <X>130</X>
          <Y>-5</Y>
        </Label>
        <X1>0</X1>
        <Y1>15</Y1>
        <X2>320</X2>
        <Y2>15</Y2>
      </Item>
      <Item id="$CI4@MIT" type="GROUP">
        <Item id="52DB@MIT" type="SIGNAL">
          <Label>
            <Text>52DB</Text>
            <X>5</X>
            <Y>30</Y>
          </Label>
          <X1>0</X1>
          <Y1>20</Y1>
          <Width>35</Width>
          <Height>10</Height>
          <Source>sgs3lr</Source>
        </Item>
        <Item id="53T.6" blockId="53T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>100</X2>
          <Y2>15</Y2>
        </Item>
      </Item>
      <Item id="57@MIT" type="SWITCH">
        <Label>
          <Text>57</Text>
          <X>10</X>
          <Y>30</Y>
        </Label>
        <X1>0</X1>
        <Y1>0</Y1>
        <Normal>DD</Normal>
        <Reverse>SD</Reverse>
      </Item>
      <Item id="53T.7" blockId="53T@MIT" type="BLOCKSEGMENT">
          <X1>-30</X1>
          <Y1>0</Y1>
          <X2>-90</X2>
          <Y2>-60</Y2>
       </Item>
    </Track>
    <Track id="TEST" X="19" Y="180">
      <Item id="$CI5@MIT" type="GROUP">
        <Item id="001BT@MIT" type="BLOCKSEGMENT">
          <Label>
            <Text>001BT</Text>
            <X>70</X>
            <Y>-5</Y>
          </Label>
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>150</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="B2D@MIT" type="SIGNAL">
            <Label>
              <Text>B2D</Text>
              <X>15</X>
              <Y>30</Y>
            </Label>
            <X1>0</X1>
            <Y1>20</Y1>
            <Width>40</Width>
            <Height>10</Height>
            <Source>sgt3lr</Source>
          </Item>
     </Item>
      <Item id="$CI6@MIT" type="GROUP">
        <Item id="3T.1@MIT" blockId="3T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>150</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="HZM1@MIT" type="LEVELCROSSING">
              <X1>60</X1>
              <Y1>-80</Y1>
        </Item>
        <Item id="$3T.TIB@MIT" type="TRAINIDBOX">
          <X1>10</X1>
          <Y1>-20</Y1>
        </Item>
        <Item id="2D@MIT" type="SIGNAL">
          <Label>
            <Text>2D</Text>
            <X>20</X>
            <Y>30</Y>
          </Label>
          <X1>0</X1>
          <Y1>20</Y1>
          <Width>50</Width>
          <Height>10</Height>
          <Source>sgt4lr</Source>
        </Item>
      </Item>
      <Item id="1A@MIT" ssid="01@MIT" type="SWITCH">
        <Label>
          <Text>1A</Text>
          <X>10</X>
          <Y>30</Y>
        </Label>
        <X1>0</X1>
        <Y1>0</Y1>
        <Normal>SS</Normal>
        <Reverse>SD</Reverse>
      </Item>
      <Item id="$CI7@MIT" type="GROUP">
        <Item id ="3T.2@MIT" blockId="3T@MIT" type="BLOCKSEGMENT">
          <Label>
            <Text>3T</Text>
            <X>30</X>
            <Y>-5</Y>
          </Label>
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>100</X2>
          <Y2>15</Y2>
        </Item>
        <Item id ="3T.4@MIT" blockId="3T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>30</Y1>
          <X2>30</X2>
          <Y2>60</Y2>
        </Item>
      </Item>
      <Item id="3@MIT" ssid="03@MIT" type="SWITCH">
        <Label>
          <Text>3</Text>
          <X>10</X>
          <Y>30</Y>
        </Label>
        <X1>0</X1>
        <Y1>0</Y1>
        <Normal>SU</Normal>
        <Reverse>SS</Reverse>
      </Item>
      <Item id="$CI8@MIT" type="GROUP">
        <Item id="3T.3@MIT" blockId="3T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>150</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="2BA@MIT" type="SIGNAL">
          <Label>
            <Text>2BA</Text>
            <X>120</X>
            <Y>30</Y>
          </Label>
          <X1>110</X1>
          <Y1>20</Y1>
          <Width>40</Width>
          <Height>10</Height>
          <Source>sgt3rl</Source>
        </Item>
        <Item id="3T.5@MIT" blockId="3T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>0</Y1>
          <X2>60</X2>
          <Y2>-60</Y2>
        </Item>
      </Item>
      <Item id="2ST@MIT" type="BLOCKSEGMENT">
        <Label>
          <Text>2ST</Text>
          <X>145</X>
          <Y>-5</Y>
        </Label>
        <X1>0</X1>
        <Y1>15</Y1>
        <X2>300</X2>
        <Y2>15</Y2>
      </Item>
      <Item id="$CI9@MIT" type="GROUP">
        <Item id="53T.4@MIT" blockId="53T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>150</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="53T.5@MIT" blockId="53T@MIT" type="BLOCKSEGMENT">
          <X1>150</X1>
          <Y1>30</Y1>
          <X2>120</X2>
          <Y2>60</Y2>
        </Item>
        <Item id="52DA@MIT" type="SIGNAL">
          <Label>
            <Text>52DA</Text>
            <X>20</X>
            <Y>30</Y>
          </Label>
          <X1>0</X1>
          <Y1>20</Y1>
          <Width>50</Width>
          <Height>10</Height>
          <Source>sgt4lr</Source>
        </Item>
      </Item>
      <Item id="55A@MIT" ssid="55@MIT" type="SWITCH">
        <Label>
          <Text>55A</Text>
          <X>10</X>
          <Y>30</Y>
        </Label>
        <X1>0</X1>
        <Y1>0</Y1>
        <Normal>SS</Normal>
        <Reverse>US</Reverse>
      </Item>
      <Item id="$CI10@MIT" type="GROUP">
        <Item id="53T.3@MIT" blockId="53T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>98</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="53T.6@MIT" blockId="53T@MIT" type="BLOCKSEGMENT">
          <X1>98</X1>
          <Y1>0</Y1>
          <X2>38</X2>
          <Y2>-60</Y2>
        </Item>
      </Item>
      <Item id="53@MIT" type="SWITCH">
        <Label>
          <Text>53</Text>
          <X>10</X>
          <Y>30</Y>
        </Label>
        <X1>0</X1>
        <Y1>0</Y1>
        <Normal>SS</Normal>
        <Reverse>US</Reverse>
      </Item>
      <Item id="51B@MIT" ssid="51@MIT" type="SWITCH">
        <Label>
          <Text>51B</Text>
          <X>10</X>
          <Y>30</Y>
        </Label>
        <X1>0</X1>
        <Y1>0</Y1>
        <Normal>SS</Normal>
        <Reverse>SD</Reverse>
      </Item>
      <Item id="$CI11@MIT" type="GROUP">
        <Item id="53T.1@MIT" blockId="53T@MIT" type="BLOCKSEGMENT">
          <Label>
            <Text>53T</Text>
            <X>20</X>
            <Y>-5</Y>
          </Label>
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>150</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="52B@MIT" type="SIGNAL">
          <Label>
            <Text>52B</Text>
            <X>120</X>
            <Y>-15</Y>
          </Label>
          <X1>100</X1>
          <Y1>0</Y1>
          <Width>50</Width>
          <Height>10</Height>
          <Source>sgt4rl</Source>
        </Item>
        <Item id="53T.2@MIT" blockId="53T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>30</Y1>
          <X2>30</X2>
          <Y2>60</Y2>
        </Item>
      </Item>
      <Item id="$CI12@MIT" type="GROUP">
        <Item id="001DT@MIT" type="BLOCKSEGMENT">
          <Label>
            <Text>001DT</Text>
            <X>60</X>
            <Y>-5</Y>
          </Label>
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>150</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="D52B@MIT" type="SIGNAL">
          <Label>
            <Text>D52B</Text>
            <X>115</X>
            <Y>-15</Y>
          </Label>
          <X1>110</X1>
          <Y1>0</Y1>
          <Width>40</Width>
          <Height>10</Height>
          <Source>sgt3rl</Source>
        </Item>
      </Item>
    </Track>
    <Track id="TEST" X="19" Y="270">
      <Item id="(002B)@MIT" type="BLOCKSEGMENT">
        <Label>
          <Text>(002B)</Text>
          <X>70</X>
          <Y>-5</Y>
        </Label>
        <X1>0</X1>
        <Y1>15</Y1>
        <X2>150</X2>
        <Y2>15</Y2>
        <Signalization>NO</Signalization>
      </Item>
      <Item id="$CI13@MIT" type="GROUP">
        <Item id="1T.1@MIT" blockId="1T@MIT" type="BLOCKSEGMENT">
          <Label>
            <Text>1T</Text>
            <X>116</X>
            <Y>-5</Y>
          </Label>
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>242</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="4D@MIT" type="SIGNAL">
          <Label>
            <Text>4D</Text>
            <X>10</X>
            <Y>30</Y>
          </Label>
          <X1>0</X1>
          <Y1>20</Y1>
          <Width>35</Width>
          <Height>10</Height>
          <Source>sgs3lr</Source>
        </Item>
        <Item id="1T.2@MIT" blockId="1T@MIT" type="BLOCKSEGMENT">
          <X1>242</X1>
          <Y1>0</Y1>
          <X2>214</X2>
          <Y2>-28</Y2>
        </Item>
      </Item>
      <Item id="1B@MIT" ssid="01@MIT" type="SWITCH">
        <Label>
          <Text>1B</Text>
          <X>10</X>
          <Y>30</Y>
        </Label>
        <X1>0</X1>
        <Y1>0</Y1>
        <Normal>DS</Normal>
        <Reverse>DD</Reverse>
      </Item>
      <Item id="$CI14@MIT" type="GROUP">
        <Item id="1T.3@MIT" blockId="1T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>185</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="4B@MIT" type="SIGNAL">
          <Label>
            <Text>4B</Text>
            <X>160</X>
            <Y>-15</Y>
          </Label>
          <X1>150</X1>
          <Y1>0</Y1>
          <Width>35</Width>
          <Height>10</Height>
          <Source>sgs3rl</Source>
        </Item>
      </Item>
      <Item id="1ST@MIT" type="BLOCKSEGMENT">
        <Label>
          <Text>1ST</Text>
          <X>145</X>
          <Y>-5</Y>
        </Label>
        <X1>0</X1>
        <Y1>15</Y1>
        <X2>300</X2>
        <Y2>15</Y2>
      </Item>
      <Item id="$CI14@MIT" type="GROUP">
        <Item id="51T.5@MIT" blockId="51T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>62</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="54D@MIT"  type="SIGNAL">
          <Label>
            <Text>54D</Text>
            <X>10</X>
            <Y>30</Y>
          </Label>
          <X1>0</X1>
          <Y1>20</Y1>
          <Width>35</Width>
          <Height>10</Height>
          <Source>sgs3lr</Source>
        </Item>
      </Item>
      <Item id="55B@MIT" ssid="55@MIT" type="SWITCH">
        <Label>
          <Text>55B</Text>
          <X>10</X>
          <Y>30</Y>
        </Label>
        <X1>0</X1>
        <Y1>0</Y1>
        <Normal>SS</Normal>
        <Reverse>SU</Reverse>
      </Item>
      <Item id="$CI15@MIT" type="GROUP">
        <Item id="51T.4@MIT" blockId="51T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>0</Y1>
          <X2>28</X2>
          <Y2>-28</Y2>
        </Item>
        <Item id="51T.3@MIT" blockId="51T@MIT" type="BLOCKSEGMENT">
          <Label>
            <Text>51T</Text>
            <X>135</X>
            <Y>-5</Y>
          </Label>
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>314</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="51T.2@MIT" blockId="51T@MIT" type="BLOCKSEGMENT">
          <X1>314</X1>
          <Y1>0</Y1>
          <X2>286</X2>
          <Y2>-28</Y2>
        </Item>
      </Item>
      <Item id="51A@MIT" ssid="51@MIT" type="SWITCH">
        <Label>
          <Text>51A</Text>
          <X>10</X>
          <Y>30</Y>
        </Label>
        <X1>0</X1>
        <Y1>0</Y1>
        <Normal>SS</Normal>
        <Reverse>US</Reverse>
      </Item>
      <Item id="$CI16@MIT" type="GROUP">
        <Item id="51T.1@MIT" blockId="51T@MIT" type="BLOCKSEGMENT">
          <X1>0</X1>
          <Y1>15</Y1>
          <X2>60</X2>
          <Y2>15</Y2>
        </Item>
        <Item id="54B@MIT" type="SIGNAL">
          <Label>
            <Text>54B</Text>
            <X>35</X>
            <Y>-15</Y>
          </Label>
          <X1>25</X1>
          <Y1>0</Y1>
          <Width>35</Width>
          <Height>10</Height>
          <Source>sgs3rl</Source>
        </Item>
      </Item>
      <Item id="002D@MIT" type="BLOCKSEGMENT">
        <Label>
          <Text>(002D)</Text>
          <X>70</X>
          <Y>-5</Y>
        </Label>
        <X1>0</X1>
        <Y1>15</Y1>
        <X2>150</X2>
        <Y2>15</Y2>
        <Signalization>NO</Signalization>
      </Item>
    </Track>
  </Region>
</FieldVisual>

Answer 1

It's because it doesn't expect more than one element in your <xs:choice> within your definition of <xs:complexType name="ItemType">. Change that to <xs:choice minOccurs="0" maxOccurs="unbounded"> to fix the first error. You'll find another similar error after that, in the definition of <Track>. Change that to <xs:element name="Track" minOccurs="0" maxOccurs="unbounded"> and all should be well.