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Post by 100andthirty on Jan 23, 2024 16:09:27 GMT
The logic went something like this......... Air conditioning is a highly desirable customer amenity but the business case is not so good especially if the tunnel ventilation has to be improved. But the provision of regenerative braking which will be at its most efficient in tunnel, reduces the amount of energy (heat) disippated into the tunnel. Having three phase ac traction instead of resistance control helps too. So, there is 'headroom' to generate extra heat from air conditioning without the tunnels getting hotter than today. There should also be enough headroom for 27tph although I haven't done any calculations.
But, I hear you say, what about the service increase to 33tph or 36 tph?
The argument was that capacity increases have a superb business case. As increasing the service increases heat dissipation, there will need to be improvements to the ventilation system.
Not entirely independent of this is wind speeds in and around stations arising from higher braking and acceleration rates arising from ATO in older stations and some work may well be necessary to manage wind speeds.
Having said all that, on the Victoria line with all the changes made (new trains, new signalling, upgraded power supplies and much more frequent services), the overall energy consumption reduced compared with the old 1967 tube stock service.
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Post by 100andthirty on Jan 10, 2024 18:31:14 GMT
The downside of articulation is inflexible fixed rakes. The downside of two-bogie cars is added cost and weight. The new stock combines the two! It's not that simple. There was a requirement not to increase the load on some of the bridges that are to light rail standards despite DLR growing up to be effectively a metro. Therefore the wwight of the 5-car train wasn't allowed to be increased. Then there was the additional kit in the form of air conditioning. The current three, twin car trains have nine bogies, the new train has 10. Not a big increase. I expect that a fully walk though articulated train would probably have had 10 bogies. DLR went out to competitive tender for tese trains. They have never announced the design of the unsuccessful bid; it would be inappropriate to do so, but I suspect that some of the competition offered articulated trains. Finally, whether articulated or not, most modern trains are "inflexible fixed rakes". Every coach in a rake as a place and every coach has to be in its place.
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Post by 100andthirty on Dec 21, 2023 15:08:38 GMT
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Post by 100andthirty on Dec 21, 2023 15:05:44 GMT
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Post by 100andthirty on Dec 5, 2023 12:43:28 GMT
Further, the issue of tube trains running between main line gauge trains is a real one that will be experienced on the Metropolitan line first. It is quite challenging to design a tube train with enough strength to withstand a collision with a full size train. The load paths to dissipate collision forces get in the way of accommodating people especially drivers. THe way to deal with this is to control spacing with the signalling system with a form of ATP with suitable precautions in the event that limited movement in Restricted Manual is permitted if the ATP fails. On the QP/Harrow and Wealdstone, the signalling - tripcock/trainstop got LU, TPWS at every signal for Overgound, movement without signalling protection is very tightly controlled compared with the circumstances that led to the 1986 collision.
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Post by 100andthirty on Dec 5, 2023 12:15:06 GMT
Unless something has changed very significantly in LU over the last 10 years, an extension of the Bakerloo line to Watford Junction is unlikely ever to happen. As to an extension to Euston, I can't see any scenario where such an extension would be desirable or permitted. Switchable 3rd/4th rail operation is undesirable as would fitting 4th rail on the approaches to Euston, intermingling a tube train with main line trains on the busy approaches to Euston is undesirable, and having a platform or platforms that can olny serve tube trains and an inability for those trains to go to any other platform is also undesirable. I can't see any customer proposition that would be so compelling as to make it worth addressing any of these issues.
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Post by 100andthirty on Dec 3, 2023 7:52:23 GMT
The platform train interface issue N of Queen's Park is no different from what 2024 tube stock will experience between Rayners Lane and Uxbridge.
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Post by 100andthirty on Nov 22, 2023 12:22:45 GMT
There is an approximation of the truth in Geoff Marshall's video and other statements from this event in Germany. It was said that this train has only 10 bogies whereas a normal 9-car train would have had 18. In reality no one would have contemplated a 9-car, 18-bogie train; there wouldn't have been the space for the normal equipment let alon air conditioning. The true comparison is between the 9-car, 10 bogie train with a 7-car, 14 bogie conventional train of the same length. Still a useful saving of 4 bogies or, in the order of 20 tonnes, and circa 12 metres of underframe space..
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Post by 100andthirty on Sept 12, 2023 9:35:34 GMT
Well, my analysis is that only the class 378 has humidity control, the others only air cooling. Interesting that four different manufacturers are mentioned, S stock not being shown. Power consumption of the new Picc (and Bakerloo?) train system is not known, still under test. S stock power consumption is far above the others shown, at 21-31Kwh per car, compared to 13-15Kwh on class 710 (and 345?). The S stock failure rate is high. Of course, all but the Picc trains have roof-mounted units. I hope the underfloor units keep clean enough! Having looked at the FOIs, I doubt they were all compiled by the same person, and I strongly doubt that 17m car (S stock) is consuming twice as much energy per air conditioning unit as a 20m long class 710 or 23m long class 345. There haven't been any significant improvements in air conditioning system technology between S stock and the Aventra platform so a twice the energy consumption is unlikely. But happy to be proved wrong!
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Post by 100andthirty on Aug 21, 2023 17:00:17 GMT
There is an on-line system for booking privilege tickets run by the Rail Delivery Group that is gradually being rolled out to TfL people who are entitled to priv tickets. My wife and I have this facility but I'm aware it's not available for all yet. As with other on-line tickets, it will issue an e-ticket if that's available, but where not available, it will issue a code for collecting tickets from a ticket machine. One example, not likely to be necessary for TfL for, who have their staff Oyster cards, is for cross London tickets as LU doesn't accept e-tickets.
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Post by 100andthirty on Aug 3, 2023 11:42:34 GMT
I'm not personally against traction-voltage bus lines and jumpers. I just had he impression that LU was. Dennistoun Burney became famous for complicated solutions to basic engineering problems, such as placing the clutch and gearbox at opposite sides of the engine. He designed the famous Streamline car favoured by Edward, Prince of Wales. He worked alongside Barnes Wallis and Nevil Shute Norway on the R100 ad Howden. A brilliant man, in my view. LU has had an aversion to what are known as 'power bus lines' where a cable or cables connect all the shoes together in a unit. I believe this requirement stems from some nasty fires a very long time ago. But all trains at least from 1938 tube stock onwards have sent 600V feeds between cars. But the critical difference is that the power bus line is effectively un fused whereas all the applications that have been discussed here have some sort of fuse or circuit breaker protecting the high voltage feed.
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Post by 100andthirty on Aug 2, 2023 17:38:34 GMT
Looking along the train, it appears that the bogies on the middle car do not carry shoe gear, which stands out as a light coloured attachment on the other bogies. The motors are fed from the wheel-less intermediate cars, which are themselves connected to traction current from the intermediate motor cars. From what I can see in the photos, I reckon the feeding arrangements are like this: Shoes on car 1 feed the traction packages on car 2. These traction packages feed the motors on car 1 and the outer bogie on car 3. Shoes on car 3 feed the traction packages on car 4. These traction packages feed the inner bogie on car 3 and the bogie on car 5 adjcent to car 3. For cars 9 down to 5 its a mirror image of the above. And, as far as I know each traction motor has its own inverter.
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Post by 100andthirty on Jul 21, 2023 16:10:24 GMT
I reckon it's been raised for the journey - perhaps to fix a some gauging issue to allow the transit to Wildenrath. The coupler looks much higher than we'd normally expect.
Also, if you look closely the M door is missing and a blank panel is fitted that's got an air hose running thogu it
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Post by 100andthirty on Jun 17, 2023 9:51:16 GMT
The Jubilee line PEDs were argued to be a means to aviod flaring the tunnels to minimise windage on the platforms. But the delivered a demonstrable safety benefit. The fact that the PEDs don't completely fill the platform tunnels means that the station and tunnel vent systems are not separate. So, practically, what Chris M says is logically true.
What is sometimes not understood is that it's often the ventilation system that imposes the practical maximum capacity of modern metro systems as they often have a limit on the number of trains in the ventilation section. This limit is often one train and is enforced by the signalling system.
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Post by 100andthirty on Jun 5, 2023 15:05:21 GMT
The only thing I'm aware of is the Sub-Surface Railway and Railtrack study initiated by the Labour Government as part of the development of the PPP. About 1999, if I recall correctly. A senior ex-LU engineer worked ar Railtrack's representative. As I recall it, the idea was to be able to operate through trains across London as a sort of pauper's Crossrail. My over-riding recollection is that we all - both LU and Railtrack folk - took it incredibly seriously in public but in private thought it was barking mad (or even Barking mad!). The real Crossrail has, of course, shown what's necessary to create real extra capacity. And I've found a reference: hansard.parliament.uk/Lords/1999-07-30/debates/30ed17b7-e53c-484c-b923-96aa193ee29a/LondonUndergroundSub-SurfaceLinesRailtrackResponsibilities
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Post by 100andthirty on Jun 5, 2023 6:34:57 GMT
And the first set of double doors behind the cab is narrower then the others.
BTW, the cab door, like all the others are outside sliding doors with no door pockets.
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Post by 100andthirty on Jun 4, 2023 12:06:25 GMT
S stock was originally intended to have a floor at approximately the same height as D stock - circa 1100mm. On the basis that it was to use equipment and bogies that were basically the same size as the 2009 stock the question was asked, "could we have a lower floor" and thus avoid building humps at everyplatform for level access wor wheelchairs etc. Of courese we know the answer and a floor height of 980mm was the result with a flat floor throughout.
But.......it's a metro train, top speed 60 mph. The Greater Anglia Stadler trains have had to have many compromises to achieve the lower floor, including steps to access seats and many ramps to negotiate the passage ways between cars and equipment compartments adjacent to motor bogies. It is a very long passageway between cars 6 and 7 on a 12-car class 745. Even the Liverpool trains are not ramp free.
Another issue for Crossrail when making platform height/floor height decisions was the existance of 1100mm platforms at Heathrow.
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Post by 100andthirty on Mar 21, 2023 6:28:43 GMT
Tripcocks are mounted on the shoebeam which is effectively rigidly located on the axleboxes. The only lateral motion (sway) is that of the wheel flanges between the gauge faces of the rails. But at tripcock testers, check rails are provided to control the lateral motion. The provision of check rail hasn't been a requirement for several years now. The first to not have them were at Ladbroke Grove in 2012 (when they were converted from temporary installations to permanent). Thanks for the correction Tom. To be fair, one of the benefits of siting tripcock testers in platforms is that speed is low.
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Post by 100andthirty on Mar 20, 2023 9:38:15 GMT
I presume this is because of sway. A tripcock tester requires the tripcock to pass through a relatively small aperture with a small margin of error. At a higher speed, the greater the likelihood that a working tripcock will be positioned incorrectly for the tester. Tripcocks are mounted on the shoebeam which is effectively rigidly located on the axleboxes. The only lateral motion (sway) is that of the wheel flanges between the gauge faces of the rails. But at tripcock testers, check rails are provided to control the lateral motion. The real reason for a speed limit over tripcock testers is to provide a positive depression of the treadle rather than a fleeting contact (rememberine that the tripcock can be knocked back a little without tripping). And, ultimately,to minimise the risk of the energy from hitting the tripcock tester at higher speed actually causing the tripcock to be tripped.
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Post by 100andthirty on Mar 4, 2023 21:51:10 GMT
I'm not sure where to start, but in no particular order:
1) Converting the 1973 tube stock to operate on the Northern line would require the Thales CBTC system and the track to train CCTV system. The former is a very big modification and the only spare space for the kit in on the trailer cars (identified when there was a plan to fit the Bombardier CBTC system well over 10 years ago to interrun with the sub-surface signalling upgrade). The Thales CBTC would have to be tuned for a far less flexible braking system which might affect stopping accuracy. Providing the equipment from redundant trains as outlined above is the easy bit, and, in any event some of it is part of the problem. 2) Higher performance is required on the Northern line. The 1973 tube stock was designed with higher performance capability which has never been used. But enabling it now would put huge strain on the traction system. 3) part of the reason for the underframe cracks on the 1996 tube stock is the additional longitudinal traction and braking forces arising from the addition of the 7th car. If 1995 tubes stock were to be converted to 7-car then they would suffer similarly. 4) it is impossible to compare reliability between lines, there are so many factors affecting it. The most extreme example being the Central and W&C - same train but very different reliability figures. One really does need to get behind the headline figures and understand what sub-systems or components are causing the failures and set about fixing them. There is also a lot more kit on the modern trains compared with the 1973 tube stock. 5) Major engineering modifications to old trains are almost always more expensive and take longer than anyone expects even after making ample allowance. D train has not been a rip roaring success, the class 769 conversion from class 319 has been extremely troublesome and 1992 tube stock engineering change has been going on for a very long time with no service date in sight.
Piccadilly line trains have become reliable because its management took the trouble to understand why it was failing and put in place the actions - in terms of people, process and eauipment to address the root causes. These principles should be applied to the other fleets.
I've responded seriously but I realise, Jimbo, that your post might have been tongue in cheek!
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Post by 100andthirty on Mar 4, 2023 16:02:58 GMT
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Post by 100andthirty on Mar 1, 2023 7:45:55 GMT
Unsurprisingly, the Investment Committee report provides a snapshot without actually explaining exactly what they are doing. My understanding is that the functionality and interfaces will be maintained and obsolete components will be replaced with new ones with the same function. So not a resignalling.
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Post by 100andthirty on Feb 24, 2023 7:43:40 GMT
4LM is the project formerly known as Sub-Surface Upgrade or SUP for short.
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Post by 100andthirty on Feb 22, 2023 13:15:33 GMT
Having read the report to the Programmes and Investment Committee, I wonder whether they have recruited someone who is not at all familiar with any of TfL's operations. I can't believe the project or programme managers actually supply such rubbish for the report. "Pull-forward" seems to be a new term and I'm not at all sure what it means. Then there is "The outstanding issue is the modification of the auxiliary power units, which are to be reworked with new and improved safer component design." This sounds very much like someone has c*cked up, but is being made to sound positive. Then there's a picture of a 1973 tube stock with a caption about 1992 tube stock and another of the D stock RAT with a caption about the track recording car. This is the stuff about which I'm familiar. Perhaps everything else is perfect? ??
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Post by 100andthirty on Feb 22, 2023 7:33:03 GMT
Doesn't sound much like March as a service date.
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Post by 100andthirty on Feb 19, 2023 18:26:04 GMT
Fingers crossed!
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Post by 100andthirty on Feb 15, 2023 9:35:43 GMT
We are wandering into the realms of an alternative universe. Based on all the posts upstram the 1983 tube stock idea was knocked on the head long before anyone thought of integrating any ATO onto it, let alone the Westinghouse solution that was chosen and failed to get fitted.
But.......all LU tube stock purchased after 1967 tube stock had a basic space allocation for ATO kit and whilst not trivial, adapting an exiting train for ATO is possible. 1996 Tube stock was adapred for a very different style of ATO compared with the Westinghouse design originally fitted...............Yes, as far as I recall, the Westinghouse ATO kit was fitted and used to control the Platform Edge Doors. I'm sure t697 will confirm.
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Post by 100andthirty on Feb 15, 2023 7:31:25 GMT
In all my experience, though, large modifications always end up taking longer and costing more than expected even when an allowance has been made for this truism.
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Post by 100andthirty on Feb 15, 2023 7:22:53 GMT
Does anyone know what the stock issues are?
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Post by 100andthirty on Feb 15, 2023 7:21:26 GMT
Rechecking the Particular Specification for the JLE rolling stock I see it is specifically for all new cars, at least at the issue A4 of October '93. Was there a pre-tender period when prospective tenderers were invited to put forward their proposals for all new vs. part reworked 83TS? I do seem to recall there would have been difficulty with tenderers taking on risks associated with the 83TS cars. I think you're probably right. It would make sense for this option to be discussed pre bid.
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