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The glass is not perfectly transparent, so you get losses due to attenuation, you can use optical amplifiers to fix that though. The other problem is dispersion (pulses getting smeared in time) which needs more involved correction.

Signal fading with distance lies (very roughly) between the square and the fourth power of distance. This depends on the level of obstacles, environmental conditions, etc. This makes it very easy for a nearby unwanted transmitter on a particular frequency to totally swamp out reception of...

Not sure about this bit. This is an interesting (if a tad morbid) read which suggests the opposite http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2763825/#S2-7title At 25kV you'd be likely to get dielectric breakdown of the skin which would significantly lower the overall impedance, making things...

Realistically the zero crossing point point does not give you any meaningful chance to let go (at least at in the 50 or 60 Hz range). As I understand it, AC is more dangerous to the body than DC at the same voltage or current, in part due to capacitative effects (the body has a lower...

I don't really see how this will make much of a difference, the actual train movements, track infrastructure, and availability of rolling stock for the routes remaining under AGA's umbrella will not be meaningfully changed. They'll still have all of the problems they do now on those routes, just...

Economic Bitcoin mining rigs are ASICs these days, there's no way to get them to do anything else of use. Public key signing algorithms and AES are nothing like hashing at any rate. Trying to brute force signatures/keys is probably not worth the bother when there are far easier and more...

There's really no need for the driver to do anything rash as has been suggested. The coal won't be upset if it arrives a day late, nor is it a big deal if the train is parked on the branch line for a while. The actual cost of this and similar incidents is a rounding error, there's no basis for...

That's a bit of a shame, I still use that site occasionally. Whilst I don't use it for rail, it's very useful for buses outside of London, and the interface is much less clunky than Travelline's.

I find this difficult to believe. What is modern and optimal now may not be considered as such in the future. That is the very nature of the word "modern" after all.

That seems dubious to me, kilometres are shorter than miles. That makes the words 'needed' and 'wanted' fairly meaningless.

This may be less true if you happen to live/travel on one of the miles in question. Economic productivity is not linear with the number of jobs. More jobs is not automatically better when the actual productive output (ie. moving x containers from A to B) is the same.

Oops, I'd forgotten about that one. I was heading up to Ipswich and there's no (timetabled at least) connection from the 00:02. Sorry :oops:

I noticed that the last train from Liverpool Street to Colchester last night (the 23:32) was also cancelled, I imagine that that didn't go down too well either. That was the train I'd booked to get home, luckily my plane landed early and I managed to get the 22:32... I've no information on...

Transmission losses are not insignificant, but they're not a deal-breaker either. Any loads such as plants would need to be connected to the main grid for reliability purposes anyway. Trying to match a source with huge daily variations, ie. a tidal barrage, with a set of plants, is unlikely to...

Given the significant price premium on car insurance for young people, and the third off due to railcards, it makes perfect sense for me to forgo having a car, at least until I'm no longer eligible for a railcard. Then again my commute is just 30-40 minutes by bike, or 20 minutes on the bus...

Heathrow and Stansted are themselves convenient termini for services to other places of interest en route. The Piccadilly line and Cross Country Birmingham to Stansted services, for example. Not being on a mainline is not necessarily a problem, as an airport is a destination in its own right to...

The work at Farringdon is hard to miss. Though for the most part all you can see is a lot of cranes in a large hole surrounded by hoarding. I'm not sure if there's a viewport, been over a month since I was last there, otherwise you might be able to get a view from Holborn Viaduct.

Why exactly is a formal complaint printed on some dead trees and hand-delivered more weighty than one with the same content delivered electronically? I'm not arguing that a lot of people still feel this way, but I can't see any objective reason for it to be so. Email is cheaper, more...

Given that tread brakes have inferior performance to disc brakes, but have the advantage of having some level of scrubbing effect, would it be possible to add some sort of tread-contact device for the purpose of removing mulch, rather than braking per se? Also, eddy-current brakes would seem...

That's not much good if you need to catch one of these services with less than 3 months notice. It'd probably make the problem of speculative reservations worse as well.