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Post by Deleted on Oct 30, 2011 1:11:48 GMT
Which is actually more efficient? Rolling up to a danger aspect or just stopping and starting again? Depends what you mean by efficient, time or energy-wise. ATO can't "coast", it either motors or brakes so while it's in motion. I mean time keeping wise |
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Post by norbitonflyer on Oct 30, 2011 14:50:56 GMT
Depends what you mean by efficient, time or energy-wise. ATO can't "coast", it either motors or brakes so while it's in motion. I mean time keeping wise The fastest times are kept by braking as late as possible - watch any motor race. But any braking dissipates energy (regenerative braking reduces, but does not eliminate, this) so only accelerating up to the speed from which you will coast to a halt at the desired point is the most energy-efficient - but gives much slower point to point times. |
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Post by Deleted on Oct 30, 2011 17:25:03 GMT
I'm guessing that in coded manual mode, a driver can exceed 85kph and not have the ATP cut in because the code is 110! Why didn't they reprogram the system with say a 90/85 code in place of the current 110/102?. on another note the bar speed which lights up on what appears to be increments of 5kph is not the clearest to read and I guess drivers could be tempted to run at slightly higher maximums to offset their more cautious station approaches!
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Post by jardine01 on Oct 30, 2011 17:58:08 GMT
I would not like to be on a 1992 stock any faster than 85kph!
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Post by Deleted on Oct 30, 2011 18:12:09 GMT
I remember them, its like sitting inside an A62 air compressor
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Ben
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Post by Ben on Oct 30, 2011 19:02:58 GMT
Well hopefully when all the bogies are done the speed will go back up. No point in running things sub-optimally! And it can be spun as an interim upgrade...
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Tom
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Post by Tom on Oct 30, 2011 21:06:23 GMT
The same applies to the victoria line but their ATO system is not as aggessive as the Centrals. Certainly in my experience Victoria Line DTG-R is more aggressive than Central Line ATO, particularly when it comes to brake rates. |
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Tom
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Post by Tom on Oct 30, 2011 21:11:31 GMT
The "ATO" system is a bit more complicated than what we read here. Most of them can have coasting regimes. The ones the Victoria Line used to have were switched out. I don't know about the Central. Are the instructions in the PAC loops? [Edit] I knew there were coasting instructions available, see "ATO" here: www.davros.org/rail/signalling/articles/central.htmlI assume it's still the same today. Can anyone confirm? [/Edit] Confirmed - the system can coast but coasting vectors aren't currently in use. |
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Post by Deleted on Oct 30, 2011 23:25:29 GMT
The "ATO" system is a bit more complicated than what we read here. Most of them can have coasting regimes. The ones the Victoria Line used to have were switched out. I don't know about the Central. Are the instructions in the PAC loops? [Edit] I knew there were coasting instructions available, see "ATO" here: www.davros.org/rail/signalling/articles/central.htmlI assume it's still the same today. Can anyone confirm? [/Edit] Confirmed - the system can coast but coasting vectors aren't currently in use. That's interesting what happens when you depart say STR towards MIE and once the train reaches speed the brakes apply every 4 seconds or so with the clunking from behind the bulkhead. Is the train not just coasting and picking up speed and then braking? Or is it motoring in the lowest power setting then braking? |
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Post by jardine01 on Oct 31, 2011 7:22:56 GMT
The 2009 stock is slightly faster than averge coming into the stations I think it is around 40mph when they enter the station and they brake very hard into the station. I thought DTG system was not in operation yet apart from stations North of Seven sisters?
I defently think the Central line ATO is more agressive and for a system which was designed in the 90's it does the job well.
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Post by jardine01 on Oct 31, 2011 7:25:14 GMT
Have all 1992's now got the new bogies fitted? It would be good if it went up to 62mph it would really cut journey times but I hope they make the ride smoother so i does not feel like it is shaking its self to pieces.
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Tom
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Post by Tom on Oct 31, 2011 9:22:01 GMT
Probably because they trust the computer to drive at full power in ATO but not the driver. Actually it's the opposite. Speed is restricted in ATO but not in CM. |
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Post by Tom on Oct 31, 2011 9:27:34 GMT
Have all 1992's now got the new bogies fitted? It would be good if it went up to 62mph it would really cut journey times but I hope they make the ride smoother so i does not feel like it is shaking its self to pieces. Actually, it doesn't. 62mph (100km/h) is only really an advantage on the sections towards Epping where stations are a couple of kilometers apart. At the west end, normally as the train reaches 100km/h it has to start braking almost immediately for the next station. Besides, have you been thrown about on a 92TS recently out west?! |
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Post by Deleted on Oct 31, 2011 9:30:50 GMT
Sorry I was under the impression power was restricted in PM. I understood that you can go faster in CM.
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Post by Deleted on Oct 31, 2011 11:32:20 GMT
The 2009 stock is slightly faster than averge coming into the stations I think it is around 40mph when they enter the station and they brake very hard into the station. I thought DTG system was not in operation yet apart from stations North of Seven sisters? DTG is on operation on the whole line. It is overlaid on the old system south of VJ12 (Highbury home signal) on the southbound, and south of highbury on the northbound. North of this, the final asset replaced system is in operation. |
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Post by jardine01 on Oct 31, 2011 16:03:03 GMT
I know this is the Central line thread but I heard when the victoria line new timetable comes trains will achive 62mph between the longer streches of track is this true?
Also on topic here why is mile end to Stratford not that fast with a top speed of 40/45mph I cannot see why 53mph is not possible along this long strech of track?
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Post by Deleted on Oct 31, 2011 16:41:48 GMT
I know this is the Central line thread but I heard when the victoria line new timetable comes trains will achive 62mph between the longer streches of track is this true? No, don't know where you heard that - design speed is 80 km/h. They would, if the ATP allowed, get to 62mph quite quickly though! |
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Post by jardine01 on Oct 31, 2011 17:46:00 GMT
I Know they are limited to 50mph but i am sure their top speed will be 62mph like all modern tube stocks?
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Post by Deleted on Oct 31, 2011 18:24:28 GMT
Why is it always exactly 62mph? Why not 60 or 70?
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slugabed
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Post by slugabed on Oct 31, 2011 18:28:29 GMT
Why is it always exactly 62mph? Why not 60 or 70? Because,regrettably,that is 100kph. |
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Post by Deleted on Oct 31, 2011 18:30:08 GMT
Ohh right, thanks
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Tom
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Post by Tom on Oct 31, 2011 22:30:37 GMT
Also on topic here why is mile end to Stratford not that fast with a top speed of 40/45mph I cannot see why 53mph is not possible along this long strech of track? It was originally envisaged that trains would go faster on this section, however the track condition prevented it which led to the removal of ATP code 9 some ten years or so ago. |
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Post by Deleted on Oct 31, 2011 22:43:02 GMT
I Know they are limited to 50mph but i am sure their top speed will be 62mph like all modern tube stocks? They are designed for 50mph (80 kmh) for all the gauging and structural cases, so no, their top speed will not be 62 mph. |
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Post by plasmid on Nov 1, 2011 0:31:26 GMT
Can't see why they haven't replaced the rest of the track between Mile End and Stratford. They've done a quarter of it on one side and an eighth of it on the other. Then again this would probably only cause queuing up towards Bank or Leytonstone if the 92ts were permitted to run down there at 50mph.
The track around Bank needs to be tilted more to reduce noise congestion, that or run the trains slower.
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Post by jardine01 on Nov 1, 2011 20:45:05 GMT
How will trains going 50mph going to cause queuing up to bank or leytonstone ? I see that they can't run at 50mph due to the track. Mile end to stratford is a long section of tunnel and I know 40/45mph is pretty fast but an extra 5mph to 50 mph will reduce journey times. Are they going to restore 62mph with these new bogies?
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Post by Deleted on Nov 1, 2011 21:40:27 GMT
Are they going to restore 62mph with these new bogies? Apparently not, the main problem was flash overs IIRC? So to keep the failure rate low, the 85KPH limit stays. |
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Post by jardine01 on Nov 1, 2011 22:33:23 GMT
What's a flash over?
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Post by Deleted on Nov 1, 2011 23:44:14 GMT
To cover some earlier points: 60mph running would make very little difference to overall running times. There are very few (long enough) sections where it could be achieved, and even on those, the difference between 85kph and 100kph is only a few seconds. Acceleration over 40mph isn't brilliant!
On a recent trip from WR to NA I was surprised at just how smooth and rock free the ride was inspite of some slightly higher than usual speeds!
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Post by Deleted on Nov 2, 2011 1:38:42 GMT
How long does it take to accelerate to 80 kph? I know 50 kph comes in 15 seconds.
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Tom
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Post by Tom on Nov 2, 2011 20:21:09 GMT
On a recent trip from WR to NA I was surprised at just how smooth and rock free the ride was inspite of some slightly higher than usual speeds! Try doing it in the opposite direction. There's a good few violent jolts on that stretch on the Westbound. |
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