The Crossrail trains will use an on-board Train Control and Management System (TCMS) to integrate information from a range of signalling systems to maintain safe and effective operations. The nature of the Crossrail route, which runs on both the existing national network and a new section of underground railway will use three separate signalling systems: Train Protection Warning System (TPWS), which is used on the mainline sections of the railway and is focused on ensuring safe operation of the railway; and two separate systems - Communication Based Train Control (CBTC) and European Train Control System (ETCS) - which use technology on the trackside and train to identify the position of trains and issue instructions to both maintain safety and enable the railway to operate with shorter distances between trains to increase overall capacity. The safe and efficient operation of Crossrail services depends on the TCMS software being able to switch between these three systems as the trains move from one part of the route to another. This transition between signalling systems has not been used in this way before on the UK's railways. Figure 12 shows which signalling systems are being used on which sections of the railway.