1. 
   Multiple Unit
   Trains that can (in most cases) be coupled together to form longer trains. Known as Railcars in other countries.
   Found op http://www.scot-rail.co.uk/page/Glossary
   
   
2. 
   Multiple unit
   The term multiple unit or MU is used to describe a self-propelled carriages capable of coupling with other units of the same or similar type and still being controlled from one driving cab. The term is commonly used to denote passenger trainsets consisting of more than one carriage. Single self-pro...
   Found op http://en.wikipedia.org/wiki/Multiple_unit
   
   

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