Centralised train control for Chch-Oamaru line

Press, Volume CXI, Issue 32679, 7 August 1971, Page 18

Centralised train control for Chch-Oamaru line

Conversion of the 130 miles of Main Truck railway between Rolleston and Oamaru to centralised traffic control, with coloured-light signalling operated from a panel in Christchurch, has now started, and will be completed in about 18 months.

The main line between! Dunedin and Oamaru is I already under centralised control, with the main control panel in Dunedin, and there is already automatic signalling between Christchurch and Dunsandel. But between Dunsandel and Oamaru there is a singleline system with crossing loops at various points so that trains can pass. TABLET SYSTEM In this area, the trains are at present controlled by the tablet system: trains can proceed between stations only when they have picked up a tablet which gives them the right to continue, only one tablet being in use in any one section at the one time.

Where the tablet system is in use, the signals used are of the mechanical semaphore variety, and the points are also controlled mechanically and switched over with a manual lever.

To convert the present system, underground cabling has to be ploughed in all along the line from Christchurch to Oamaru, dozens of sets of three-position colour-light signals have to be put up, and control panels and relays have to be installed »• Htermediate stations.

As well as this, tii.- >ops

at many of the intermediate c stations will be lengthened r to take trains of up tb about c 160 waggons as opposed to s trains ofBo or so waggons as c in the past. This is because ( the powerful diesel locomo- j tives now in use can pull c much longer trains than t could the old steam locomo- r tives. t CHERTSEY CONVERSION* At present, about 40 rail- c .ways staff are working on ! the conversion of the Chert-« sey station area, a job which < will end on Sunday evening i after about two weeks work, i From next week, the staff s stationed at Chertsey will I control trains passing 1 through their area by three-1 position colour-light signals and electrically operated points, all controlled from a small panel at the station. 1 When the Chertsey station 1 and others are eventually l I fully linked to the main con- ' s trol panel at Christchurch,' this small panel will no' i longer be used, and the conI troller in Christchurch will i take over. ' The Hinds station area and i other small areas will be coni verted next, and it is hoped to have the line between • Rolleston and Hinds linked by i three-position colour-light i control by Christmas. But the ' biggest and most tirne- ’ consuming conversion jobs 1 will be at the Ashburton and Timaru yards, where much ' more than a single, simple 1 passing loop is involved. ‘ LEVEL CROSSINGS f While the work is being t done, the opportunity will be , taken to fit level-crossing ; alarms—bells and lights—to ■ many level crossings now not so equipped. Half-arm i barriers will be put in at some crossings, including the Kyle Road crossing in Chertsey, and at crossings in Rakaia and Ashburton. When the Christchurch to Dunedin section is under central traffic control, about the tod of next year, the economics of instituting centralised traffic control on the Christchurch-Picton line will be considered. The centralised traffic-

control system had several major advantages over the old tablet and mechanicalsignal system, said the resident signals engineer at Christchurch (Mr W. D. Poysden) yesterday. The centralised system speeded up trains by eliminating the need to pick up tablets, and trains could “cross" (pass each other) much more quickly at the loops. Train drivers preferred the extra information which could be given them by three- . position colour-light signals, and the system gave added safety factors well worth having, even though the tablet system had proved very safe. FURTHER FACTOR

A further factor was that centralised traffic control made the most of scarce man-power, Mr Poysden said. Under the old system, a 24hour watch had to be kept at some small stations when trains were working, which would no longer be necessary with centralised control. As a result, staff would be , freed for other postings, Mr Poysden said.