Inspired from a question and answer last year German MEP Fabio de Masi have asked the commisioner this (26.1. 2017):
In which EU Member States do national or regional governments support (international) night train connections through various types of subsidies, and is it possible to find out which connections these are?
Which Member States have introduced lower track access tariffs?
Are these lower tariffs related to the maximum speed, the number of passengers or a particular time period (for example, will such reductions be applied only at certain times during the night)?
Answer from Mrs. Bulc (13.3. 2017):
The Commission does not have access to data on which national or regional governments support night train connections and as a result nor does it have an overview of the situation across Europe, in relation to which connections are subsidised.
To our knowledge some Member States (e.g. the United Kingdom or Sweden) have opted for subsidising night train connections in the form of a public service obligation (PSO).
As regards track access charges, according to the French infrastructure manager SNCF Réseau, France has introduced lower track access charges for night trains for both national and international journeys compared to the charges for day trains. In Spain, according to the Spanish infrastructure manager ADIF, night trains pay only track access charges in the form of direct costs, with no mark ups.
Other Member States like Italy and Germany have indicated that they plan to implement differentiated night charging. According to the Italian infrastructure manager RFI, lower night track access charges in Italy would apply for long distance PSO services only. According to the German infrastructure manager DB Netze, the new charging system in Germany will provide for lower track access charges during night hours.