Rolling-Stock
Rolling stock is a database that contains rolling material. This may be a train carriage or a bus. It may also be a airplane or a ferry, so "rolling" is somewhat misleading.
For simplicities sake, trains are used as a reference to easier understand the concepts.

Basic Element
A basic element describe a physical carriage. For example the adaption of litra A7-1 by VY.
Logical Element
A logical element describes a carriage as it would be used in a given application. For example th operator's own version of litra A7-1 as it is being used day trains on the Dovre line. The accompanying basic element is identified by id or the series/version.
Authentication
You need a valid token to use this service. In order to issue a valid token you must have a client_id and client_secret(the mechanisms for obtaining these are not in place yet).