The Next Generation Train Control and Monitoring System (NG-TCMS) represents a major innovation of the European Railway industry introducing a wireless architecture as an enabler to enhanced automation, flexible train management and increased railway capacity. This paper surveys various available and future wireless technologies matching the requirements both at train backbone and consist levels. Illustrating the challenges for a single technology to match all requirements, this paper also highlights the benefits of the upcoming 5G technology for future NG-TCMS.