rail:customer 

The authority or enterprise that ordered the transportation service, i.e., an integrated transit system

http://wiki.railml.org/index.php?title=CO:customer

Element Information

Model

rail:additionalName* , ANY element from ANY namespace OTHER than 'http://www.railml.org/schemas/2016'
Children: rail:additionalName

Attributes

QName Type Fixed Default Use Inheritable Annotation
code rail:tGenericName optional 
for typical, specific abbreviations, used in different systems with the same understanding
description rail:tElementDescription optional 
should be interpreted in its elements' context, substantiates the name
id rail:tGenericID required 
XML-file-wide unique identity is required for later referencing that element
name rail:tGenericName optional 
should be interpreted in its elements' context (e.g. track/name, vehicle/name)
xml:lang xs:language optional 
In due course, we should install the relevant ISO 2- and 3-letter
codes as the enumerated possible values . . .
Wildcard: ANY attribute from ANY namespace OTHER than 'http://www.railml.org/schemas/2016'

Source 

<xs:element name="customer" type="rail:tCustomer" minOccurs="0" maxOccurs="unbounded">
  <xs:annotation>
    <xs:documentation>The authority or enterprise that ordered the transportation service, i.e., an integrated transit system</xs:documentation>
    <xs:documentation source="http://wiki.railml.org/index.php?title=CO:customer"/>
  </xs:annotation>
</xs:element>

Sample