Handing responsibility for track and signalling to train-operating franchises in the UK could result in further fragmentation, undermining safety, the Rail, Maritime and Transport union has said.
The union made the remarks ahead of the UK Government's publishing of an interim report on rail spending.
The union said that private rail operators were looking for track and signalling deals, which could lead to massive confusion due to fragmentation, particularly where the track is shared by multiple operators.
The union said that to achieve vertical integration infrastructure, all operations should be re-united in a single entity with a single command structure with safety as its core principle.