The concept from the company
<a href="http://www.pfa.de/">PfA</a>
for refurbishing older passenger carriages
with new aluminum superstructures, originally called <em>PumA</em>
(<b>P</b>fA-<b>U</b>mbaukonzept <b>m</b>it <b>A</b>luminiumaufbau),
was in early 2000 renamed <em>Modus</em>
(<b>Mod</b>ulares <b>U</b>mbau<b>s</b>ystem)
due to naming conflicts with an automobile producer.