198703 – Leeder & McCutcheon – Marton-Hamilton Computer Based Centralised Traffic Control System

New Zealand’s Railway system is characterised by a predominance of single line track and by mainly freight traffic. It is not surprising therefore, that Centralised Traffic Control should be appropriate to such a railway, but what many would not realise, is that it has indeed been in use by NZR for close to 50 years. As traffic densities have grown CTC working has been upgraded and extended over much of the network.

The first relay based CTC system was commissioned in 1938 south of Te Kuiti, and since that time, successive technologies have been embraced by. NNZ Signals Management. Most of these technologies are still in use today, ranging from relay based systems through to electronic systems using germanium semi – conductors, followed by High Level Logic, then CMOS, and finally a computer based system.

Rationalisation and upgrading of North Island Main Trunk CTC schemes has provided the impetus for-this latest CTC scheme which will control a total of 320 km of track from Marton in the South to Hamilton in the North, with a single control centre close to the centre of the system at Taumarunui (see diagram 1). The system provides up to three operators controlling a total of 37 crossing loops, and when fully commissioned, will have replaced three earlier systems, together with a number of local control installations. This paper describes this new system and its staged implementation in parallel with the resignalling contract.