class411
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Post by class411 on Jul 31, 2016 7:51:40 GMT
In many paces, alongside tracks (not sure if I've ever seen them beside LU tracks), you can find pillars with a panel of solar cells (about 50cm sq) and a little 'windmill'.
They've been around for quite a few years now.
Clearly some sort of renewable energy system, but what do they actually power?
And how can they be cost effective, given the relatively small amount of power they can be relied upon to generate, given that there is always infrastructure for cabling already present nearby?
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Chris M
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Post by Chris M on Jul 31, 2016 8:57:06 GMT
I've always assumed they are powering a single bit of kit, and will have a battery in the assembly somewhere, so they don't need to generate much electricity. What they are powering though I can't help with.
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Post by norbitonflyer on Jul 31, 2016 9:01:52 GMT
Providing a power supply to remote locations, even when there is communications trunking, is problematic. (Althoigh on private railway property the problem of theft or hazard to the public is less than for roadside cabinets on the telecoms industry.
Whether these are emergency backup or the only electricity supply I don't know. You see them on motorway emergency telephones as well. I imagine they charge a battery so a continuous supply of sun/wind is not necessary.
Next to an active railway the supply of wind is fairly reliable, reliablless steady than on a motorway.
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class411
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Post by class411 on Jul 31, 2016 10:00:01 GMT
I'd assumed they would include a battery for backup, but they are still a puzzle:
1) They could not be used for any safety critical application because you simply could not guarantee power.
2) They couldn't be used to transmit data, because that takes quite a bit of energy.
3) They look quite expensive.
4) They are sometimes physically co-located with other powered equipment (so why use them?).
5) There are a lot of them about, but they are not at every instance of anything obvious (e.g. junction, signal, signal box).
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Chris M
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Post by Chris M on Jul 31, 2016 19:48:06 GMT
I think you could use them for something safety critical ''iff'' lack of power results in a failsafe condition. e.g. if it's powering a signal, then no power = no apsect, which (AIUI) must be treated by divers the same as it displaying its most restrictive aspect. It might disrupt the service but nothing worse than that.
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Post by Deleted on Jul 31, 2016 20:03:26 GMT
I think you could use them for something safety critical ''iff'' lack of power results in a failsafe condition. e.g. if it's powering a signal, then no power = no apsect, which (AIUI) must be treated by divers the same as it displaying its most restrictive aspect. It might disrupt the service but nothing worse than that. Yes, an unlit signal must be treated as though it were displaying its most restrictive aspect, and yes you are supposed to know the rough location of the signals on the routes you sign, and you should ideally stop at an unlit signal even at night, but it's not that failsafe really! It can be hard to stop at an unlit signal, hence lamp proving. If a main signal is unlit, the signal in rear will revert to/remain at danger. Which is fine, unless a train is on the approach, in which case you could get a category B SPAD, which is safe, but not something you just let happen if it gets a bit cloudy. However, I'm really not sure I see any reason why the windmill/solar cell shouldn't be providing power when it's able to supply power, with a mains connection to supply power as and when required, that's what I assumed the case would be. This, over an entire line, over an entire year, will probably add up to a decent cost and energy saving, without one ever having to trust to the weather holding out. |
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Post by philthetube on Jul 31, 2016 22:23:27 GMT
I cannot see unreliable power supplies ever being used for safety critical equipment, to be fair a signal with a failed red aspect does fail in a safe way as the train stop would trip any train passing it.
There are solar panels on the Chesham branch to power the lights on the lineside telephones.
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Post by Deleted on Jul 31, 2016 22:41:39 GMT
I cannot see unreliable power supplies ever being used for safety critical equipment, to be fair a signal with a failed red aspect does fail in a safe way as the train stop would trip any train passing it. That's true on LU, but much less so on Network Rail. |
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Post by tjw on Aug 1, 2016 7:44:15 GMT
I have worked with signalling systems that used batteries as a back up when the mains went down. I suspect that these renewable systems are trickle charging the battery that only comes into use when the mains power fails.
As for reliability anyone here attached a voltmeter across a solar panel in different light intensities? With the right size of panel you would have a reliable power source for recharging a battery, even in the winter!
I have seen LT bus stops with LED lights that are charged by a solar panel, also some LT bus shelters have solar panels on the roof.
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Post by Deleted on Aug 1, 2016 18:43:35 GMT
I am sure I have seen what appears to be a box with a solar panel on top on the side of the tracks on the pic line (Uxbridge branch).
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