Noun
A locomotive and carriages coupled together to form a unified set of equipment.
a self-propelled electric or diesel multiple unit, consisting of a fixed number of permanently coupled passenger vehicles.
Source: en.wiktionary.orgThe latest record is held by a SNCF TGV POS trainset, which reached convert in 2007, on the newly constructed LGV Est high-speed line. Source: Internet
Similarly, the term trainset refers to a group of rolling stock that is permanently or semi-permanently coupled together to form a unified set of equipment (the term is most often applied to passenger train configurations). Source: Internet
The country constructed the Direttissime railways connecting major cities on dedicated electrified high-speed track (although not as high-speed as would nowadays be called high-speed rail) and developed the fast ETR 200 trainset. Source: Internet