That would be illegal under EU competition law.
EC Directive 91/440 mandated the significant separation of infrastructure and train operations. As a result France separated off RFF from SNCF in 1997.
Germany, Austria and others on the other hand have separated infrastructure from train operations but have kept them under the same holding company. The EC for many years felt that Germany and Austria were flouting 91/440. When this finally came to court in 2012 the EC lost. The ECJ found that the separation of train and infrastructure operations in DB and ÖBB were sufficient.
The EC now wishes to introduce the 'Fourth Railway Package' very soon and this will mandate full separation of infrastructure and train operations. However, due to severe resistance by Germany, France etc, a derogration would allow certain countries which have train and infrastructure operations under the same company to continue with such an arrangement.
This is why France, which separated RFF and SNCF due to 91/440, is rushing back to reintegrate them.