Nu har jeg været ude at lede på nettet og har blandt andet fundet dette

15) Reversing (RV)
The Reversing mode allows the driver to change the direction of movement of the train and drive from the same cab, i.e. the train orientation remains unchanged. This shall be possible only in areas so marked by trackside. Reversing areas shall be announced in advance by trackside. This mode is used to allow the train to escape from a dangerous situation and to reach as fast as possible a “safer” location. In this mode a ceiling speed and an allowed distance are supervised.

Teksten findes i dette dokument

http://www.railwaysignalling.eu/wp-content/uploads/2014/08/ERTMS_ETCS_signalling_system...

.... og forsidetegneren er jo kendt her i Danmark