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Post by croxleyn on Jan 18, 2021 19:03:11 GMT
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Post by croxleyn on Dec 31, 2020 11:37:35 GMT
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Post by croxleyn on Dec 30, 2020 10:57:17 GMT
One advantage of AC over DC, especially for a catenary, is that an arc fed by AC will tend to self-extinguish, whereas DC will continue for ever. If the pantograph power collector is graphite, it will burn very effectively.
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Post by croxleyn on Nov 18, 2020 18:25:50 GMT
www.google.co.uk/maps/@51.6463675,-0.3858067,3a,75y,71.35h,90t/data=!3m7!1e1!3m5!1sUS0oxj7yTcjC30dqkyxIXA!2e0!6s%2F%2Fgeo0.ggpht.com%2Fcbk%3Fpanoid%3DUS0oxj7yTcjC30dqkyxIXA%26output%3Dthumbnail%26cb_client%3Dmaps_sv.tactile.gps%26thumb%3D2%26w%3D203%26h%3D100%26yaw%3D61.455505%26pitch%3D0%26thumbfov%3D100!7i13312!8i6656?hl=en&authuser=0 Note: You may need to copy the URL above into Google Maps to view. If you are not aware, the clock symbol/icon next to the location allows you to look back at historical shots: www.google.co.uk/maps/@51.646369,-0.3858008,3a,75y,71.35h,90t/data=!3m7!1e1!3m5!1sb4lDcbmLYm78Xv7Fi1o3PQ!2e0!5s20080801T000000!7i13312!8i6656?hl=en&authuser=0 shows the triangular warning sign in 2008: the next in 2012 shows the round mandate!
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Post by croxleyn on Nov 2, 2020 19:30:23 GMT
On another tax note when you use gift aid regularly for a donation my tax code was reduced one year but it has just been upped again. If you are taxed at the high rate (40%), it's something like that the taxman deducts all Gift Aid donations from your total income, effectively giving you about 10% of your donation back, as well as the 25% to the charity. So if you're just on the threshold, it's worth considering which tax year you declare it in.
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Post by croxleyn on Oct 17, 2020 8:09:02 GMT
I wonder if, had we not already built third rail systems, the powers that be would allow such a thing to be built today. Probably not. The authorities are against extensions of ground level electrification in open section railways. But just imagine what a cat's cradle would be needed for overhead wiring... At every rail switch, a tensioner is needed for the new-starting catenary, so for the likes of Waterloo, and especially Victoria, with the throats being full of track and points anyway, where would all the masts be fitted in?
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Post by croxleyn on Sept 9, 2020 18:28:50 GMT
The problem with any sort of public test is What happens if a person is identified? You might need police to somehow arrest the individual, who's likely to be not prepared to "come quietly". They would probably remove mask and start shouting so causing panic. It certainly wouldn't be within the remit of a CSA.
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Post by croxleyn on Sept 1, 2020 16:59:22 GMT
Of course the middle to end gap ratio will swap depending on the direction of travel if platforms are on opposite sides of the same track pair, or an island platform. And what's to say that the curve remains a constant radius along the platform length? So, each door plate extension will need to be calibrated for each platform. Does a carriage tip further depending on passenger load? So are strain gauges needed on the carriage suspension to compensate? What a load of variables to cope with.
And, of course, the plate has to be in place before the doors are open: the video shows almost a second delay, which all slows down a service.
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Post by croxleyn on Aug 7, 2020 16:38:25 GMT
In theory it could be done but it very much depends on the design. Years ago I built a controller for a battery operated engine for the Watford Miniature Railway, but didn't get the prototype quite right. Upon trying to reverse drive, the electronics vapourised! The second version needed a motion sensing interlock as being series configured the motor would effectively regenerate into a short-circuit, locking it solid!
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Post by croxleyn on Jul 22, 2020 19:35:33 GMT
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Post by croxleyn on Jul 11, 2020 16:40:18 GMT
All of the above comments could be made regarding closing ticket offices, at least in the suburbs. Money was spent blocking off the windows on the "public" side of the gateline: they're still needed on the Excess fares side. At Croxley this makes it unnecessarily difficult to attract the person's attention when they're working in the office and I need some assistance.
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Post by croxleyn on May 10, 2020 16:10:19 GMT
For those enjoying TV documentaries, Tim Dunn has done a good presentation on Down Street station, together with other railway edifices. This plus the second episode are available on UKTV Play. Further episodes are live on "Yesterday" channel, Tuesdays 8pm / Saturdays 11pm.
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Post by croxleyn on Apr 9, 2020 17:28:07 GMT
With a quick detour to canals... Some years ago I designed a spiral lock, a cross between the Falkirk Wheel and the Barton Swing Aqueduct, the advantage of all those being to save a lot of water. The complete caisson would rotate on the sloping curve. Whether the Canal & River Trust, to whom I gave the design would ever use it I know not, but it was a bit of fun...
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Post by croxleyn on Apr 6, 2020 19:14:32 GMT
In the 90's I used a Paternoster daily at GEC Borehamwood. As a joke for newcomers, an old hand would loop the top, doing a handstand to make it seem the whole cabin rotated!
The mechanics are extremely simple: in the video the rim of one chainwheel can be seen in the loft, and the front top right corner of the cabin is fixed to one link-pin of that chain. There's a second chainwheel offset to the rear (one cabin's height below), where a second link-pin is attached to the diagonally opposite cabin corner. Two further chainwheels sit in the sump, plus a motor. That's it!
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Post by croxleyn on Mar 22, 2020 9:59:25 GMT
With the opposite embankment so steep, I would have thought that this will reflect far more sound via the higher incidence angle than what the wall is designed to refract. And its effects will change significantly with the amount of vegetation over the seasons, and also moisture level of the ground...
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Post by croxleyn on Mar 1, 2020 12:17:45 GMT
Quote was: Mind you, the rats at Mile End had no difficulty with the live rail on the north side of the Central EB. Still haven't had an explanation of that.
It's quite likely that animals can sense the 700V of the conductor rail - even a human would probably feel the electric field if holding your face close by... One can definitely feel the static on a rubbed balloon.
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Post by croxleyn on Mar 1, 2020 12:04:46 GMT
Are all points/switches designed to be used bi-directional, or would those normally only used one-way need to be fixed for reverse running?
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Post by croxleyn on Feb 25, 2020 18:53:52 GMT
For those interested in Power Generation, visit Gridwatch. Shows daily, weekly &c power usage in the UK by energy type, and what we get from/supply to European mainland.
What amazes me is how much electricity is consumed in the small hours.
If the Frequency is high, that means too much electricity is being generated, and vice-versa.
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Post by croxleyn on Feb 23, 2020 19:24:34 GMT
How much would it cost to record "Please press the door button to open it", played just before station arrival?
Probably a ridiculous amount of money if it's not already in the system...
But what to do for the passengers waiting outside?
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Post by croxleyn on Jan 21, 2020 20:05:25 GMT
Or Watford Junction, West Watford, Croxley & Rickmansworth. Battery running at street level could be done across the Two Bridges (single track), and the majority of the original Met Line Xtension £400+million could be saved without Two Bridges viaduct or lifts at Cassiobridge station.
With all the new housing being shoe-horned into West Watford, it's still warranted.
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Post by croxleyn on Jan 11, 2020 18:29:52 GMT
A possibly naïve question... Why does the Southbound need to use the siding before reversing and crossing over to the Northbound? Why not just stay on the slow up line? Thanks
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Post by croxleyn on Dec 3, 2019 20:30:57 GMT
Closing ticket offices had many benefits. Sadly this is one of the cases where something simple has become significantly harder by not retaining any. From a traveller's viewpoint, what might these benefits be?
At Croxley, there's just the one entrance, and the on-site staff member might be easily found in the office, or very occasionally helping someone in the foyer.
Now, with the window on the "public" side of the gateline having been blocked, it's difficult to attract the individual's attention - you have to lean over the barrier and shout/wave. When the gates are locked open you know you're not going to find them...
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Post by croxleyn on Sept 29, 2019 9:18:22 GMT
I presume that the contactless only system could have a database of specific cards being railcard-linked - as far as the user is concerned, that would be no different to having railcard- and also non-discount- oyster (visitor) cards as I have. Whether the method of fare calculation could work efficiently enough without the local (card chip) knowledge of the Oyster discount I couldn't begin to guess. But there must be a lot of children without contactless... Also ticketing staff would need to be trained in the management of these cards, which of course are regularly renewed... Could the Oyster system also work like this? I wonder whether TFL benefit in cash-flow terms as Oyster is always topped up before use, with a single bank charge (they've had £9 on my visitor card for ages), whereas contactless will presumably incur daily charges.
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Post by croxleyn on Aug 31, 2019 16:17:35 GMT
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Post by croxleyn on Aug 20, 2019 19:00:54 GMT
So, could one actually put points in, back onto the NLL which would be set "through" when the terminating train arrived - after all there wouldn't be anything approaching on the NLL.. Not sure I understand this - how could you be certain there would be nothing approaching on the NLL? The NLL service is quite frequent these days, so I hear. Sorry, I meant the Barking Line that the train had just travelled along before branching into the platform track.
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Post by croxleyn on Aug 18, 2019 10:01:21 GMT
Fair comment. So, could one actually put points in, back onto the NLL which would be set "through" when the terminating train arrived - after all there wouldn't be anything approaching on the NLL. Then the points would be reverted to mainline use when the train was safely stopped in its correct position, at the same time that the east end bay entry points were switched? Then I guess the What-If brigade will whinge at the possibility of fouling the nearby diamond cross-over...
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Post by croxleyn on Aug 17, 2019 22:26:09 GMT
A quick look at Google satellite view (possibly out of date) suggests that the buffers could be moved almost one carriage length westwards. With no space for a platform extension, could one SDO that end?
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Post by croxleyn on May 29, 2019 17:26:06 GMT
Out-of-Station Interchange. Beware that most of the "Under 10 minute walk" dotted links are OSI, but not all, for example Harringay Green Lanes to Manor House.
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Post by croxleyn on Apr 20, 2019 20:01:51 GMT
Google maps also provides a Paris "transit" layer option, as per London, identifying Metro, RER and Tram lines.
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Post by croxleyn on Apr 11, 2019 17:58:01 GMT
Croxley Metropolitan station car park is always included in the Three Rivers building land assessments, so it's not just SK! There have even been rumours to build right across the tracks + platforms. Remember Tesco at Gerrards Cross?
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