Board Thread:Questions and Answers/@comment-99.126.74.115-20150810203444/@comment-26090008-20150810211035

Not all locos and wagons belong to a set, but many do. This page describes the concept of a set:

http://trainstation.wikia.com/wiki/Category:Train_Sets

On this Wiki, sets have special pages, with links to the individual elements of the set. For example: RegioPanter I

In the in-game Shop, the set to which a particular item belongs to is listed in Italics. For example, the DB 240 Aero locomotive belongs to the DB Aero Freight set. If there's no italic text, that item does not belong to a set.