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CABLES AND CABLE ACCESSORIES


Lessons from Down Under – and Derby


RTM readers got in touch with solutions to the problem of cable theft and vandalism, including Rob Jones from Australia...


He said: “I have been working for the Public Transport Authority in Western Australia for the last two years. When I was with Network Rail, cable theft was an in- creasing problem. One of the key differenc- es between the UK and Western Australia, particularly in the electrified areas, is that instead of bonding every mast to the trac- tion return rail, we connect the masts with aerial earth wire in order that not every mast requires bonding to the traction rail. Nothing was worse than spending a day digging in new traction bonds for them to go missing a few days later.


“We have also had trials with ADSS ca- ble fitted to overhead structures and a roll- out of this technology is currently under- way, particularly focused on our Northern Suburbs route and the new extension being built to it. Other comms and signalling ca- bles are in deep pits and laid underground through connecting conduit. Network Rail may fear this prohibitively expensive and awkward in some areas of the network.


“The other point to that is that the pit is in effect a confined space and may re- quire training for employees to enter the space. Unfortunately, simply leaving ca- bles in above-ground troughing, and where in some cases half the trough lids are broken or missing, is inviting to the op- portunist thief.


“Insofar as other rail operators go, it is my belief that US-based SEPTA hang their signalling and power cables from the electrification structures in the over- head electrified areas. You would have to be pretty determined and silly to try to steal it, though I’m sure there will always be an element who will try.


Readers offer tips from


around the country, and the globe, on the best way to


install and secure cabling in the rail industry.


“For the hardened thief, it is not uncom- mon for them to simply steal cable straight out of a depot. Only high vigilance and per- haps overt security presence during times when depots are empty could help. It is really a case of determining the feasibil- ity of such measures against the cost and disruption of cable theft in the long term. There is opportunity and means to reduce cable theft but it is unlikely that it can be completely eliminated.”


Another railwayman, signalling installation estimator Terry Kight of Derby, said: “In the 1970s we had a ‘mole-plough train’ which buried the cables at least a metre deep; some of the problems were the cable


being stretched and breaking down some of the cores, and it was hard to get to if you needed to install additional equipment but – at least we never had it stolen.


“Then we tried putting locking devices on the troughing, but the thieves just smashed the troughs to get at the cable, then tied the end to a Land Rover and pulled it out. We have tried SmartWater on the cables, but the scrap dealers just took the copper without question. We had warning devic- es and IDs fitted to the cables so that if they were cut an alarm sounded, but the BTP always (well, most times) missed the thieves.


“The cable turned up at the scrap dealer; he paid a lower price because of the ID marks but still bought the cable without question.


“We now have fibre-optic cables but the thieves do not know what it is until it is cut. Electric power cannot travel down a glass cable; it has to be copper or aluminium.


“The answer is to fully bury the cable route, then every 20 metres or so fill it with ex- panding foam. This will prevent the cables pulling through it if the thieves dig down to the route. To access it legally we would need chambers every 500 metres and to make sure that it is a one-piece unit with a secure lid. This chamber would also act as a joint box, pretty much as BT do.


“The biggest deterrent would be to fine the scrap dealers the value of their business if they are found to have railway identified cable on their sites.”


Another solution came from reader Richard Debenham, who said: “Each large cable could be made to have additional small wiring cables attached so that if the main cable is cut, the additional attached small wiring cable would also break and send an alarm signal to the manned signal box at the very moment the main cable is cut.


“Alternatively, if the main cables are lay- ing in conduits or trenches, then pressure sensitive switches could be attached to the cables so that if the cable is lifted then the pressure sensing switches could be activated to send an alarm to the manned signal box.”


TELL US WHAT YOU THINK opinion@railtechnologymagazine.com


rail technology magazine Feb/Mar 11 | 79


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