|
|
Post by melikepie on Nov 15, 2022 15:11:30 GMT
Thought I would ask a trivial question. Which tunnel portal has the steepest gradient, or what are tge gradients?
It is my understanding the portals are located at Plumstead, North Woolwich, Custom House, Pudding Mill Lane, Royal Oak and I suppose I should include the Silvertown and Royal Albert ones.
|
|
Chris M
Global Moderator
Forum Quizmaster
Always happy to receive quiz ideas and pictures by email or PM
Posts: 19,397
|
Post by Chris M on Nov 15, 2022 21:05:17 GMT
|
|
|
|
Post by d7666 on Nov 15, 2022 21:40:10 GMT
1:27 max. It was posted in a forum somewhere, and which I copied the text, but not where it came from, the actual XR gradients as built: 1:27 Pudding Mill Lane portal to around Eleanor Street 1:28 either side of Woolwich station 1:30 at other places incl. other portals The reason this came up on the other forum is pre-Crossrail, the post 1990 rebuild gradient of 1:29 up from City to Blackfriars*** on Thameslink was used - the value of 1:29 that is - within all main line multiple unit procurement specification as the maximum on any currently open NR main line. Traction kit must be capable of restarting a stationary train+++ on that grade with 50% traction power isolated. In discussing that, someone commented it had possibly now been changed to 1:27 - I enquired why - and those XR gradients were given as the answer. *** there is also a very short 1:29 to the immediate west of Farringdon on Thameslink ex-widened lines section - but emphasis on this one is very short +++ and trains stopped between City and Farringdon on that grade is a routine occurenc;e I see it and been on them often enough; small wonder they specified it - especially as a southbound train has just done its AC > DC transition at BFR (or CTK in default) and 700s (like 345s) consist of two seperate section that are not interconnected traction power wise _ possible scenarios are that one half could fail to changeover so the other half has to be able to move the complete train. Somewhere I have the 345 spec but not on hand; I am sure it will go into this somewhere for the XR route. |
|
|
|
Post by d7666 on Nov 15, 2022 22:19:09 GMT
Found the spec.
1 in 27 is mentioned in it, but under braking .... the train must be capable of holding on 1 in 27 .....
But it is an earlier evolution version of a 345, the motor coach | trailer coach configuration is different.
|
|
|
|
Post by d7666 on Nov 15, 2022 22:49:46 GMT
It is annoying these days how difficult it is to find out basic basic data like a gradient profile of a newly constructed line.
In days gone by - that is in the days when railway magazines were not full of corporate media soundbytes from pre-processed scripts and advertisorial articles - a full proper technical article on the core civils and electricals as well as the trains would have appeared by now.
Digressing, the last piece of main line rolling stock delivered to BR that had a full traditional unbiased new product write up avoiding contractual confidential no publicity clauses was CLass 58 locos back in 1983. Nothing since then: 1984 was the beginning of BR sectorisation. Yes something always gets written somewhere, but always with as many gaps as gen given. I can't remember the last time any LU stock had a full technical write up in any commericial mag ? I don't mean retrospective looking backwards historical items compiled after years of life, I mean gen at introduction. 3-4 years back I wrote a major article on Thameslink 700s for Todays Railways; one of the things I tried to do there was mimic the type of thing that used to appear in Modern Railways under Geoffrey freeman Allen editorship. There were still holes in the result. 345s (and indeed S-stock) are big gaps in this respect in the general commercial public domain. Perhaps I ought go try make some money .........
|
|
|
|
Post by d7666 on Nov 15, 2022 23:26:13 GMT
|
|
|
|
Post by brigham on Nov 16, 2022 9:03:09 GMT
A bit like Fifteen Floors...
|
|
|
|
Post by d7666 on Nov 23, 2022 22:12:10 GMT
Bit more gen.
The 1 in 27 has a derogation to exist.
I found this another document, not in public domain, where it states the 1 in 27 has a derogation from the applicable TSI. The TSI limit is 1 in 28.5 (which is probably the importance of the previous 1 in 29 I stated upthread in connection with main line specs / 700s / Thameslink core).
Same document does not mention the 1 in 28s at Whitechapel though.
|
|
|
|
Post by stapler on Nov 24, 2022 18:19:37 GMT
What, for comparison, is the gradient on Central Line EB and WB to Stratford Station? I seem to remember they had to float Loughton Branch Junction signal box on a raft of concrete to make the EB grade acceptable....
|
|
Chris M
Global Moderator
Forum Quizmaster
Always happy to receive quiz ideas and pictures by email or PM
Posts: 19,397
|
Post by Chris M on Nov 24, 2022 18:53:02 GMT
This 2015 post by North End has some figures for the Central line, but not for the sections either side of Stratford, suggesting that they are not among the steepest on the line. This 2017 thread is also worth a read, although it doesn't answer the question either. In a 2012 post mrfs42 estimated the gradients at Stratford to be about 1 in 31, and that thread also contains gradients (estimated and confirmed) for a few other points on the network In 2019 TfL refused a freedom of information request for gradients and speed limit data for the Central line. tubeprune notes on his website that (at least as of 2003) the steepest gradient on LU is 1 in 28 or 3.57% - between Bow Road and Bromley By Bow, District Line.
|
|
|
|
Post by revupminster on Nov 24, 2022 19:45:42 GMT
This 2015 post by North End has some figures for the Central line, but not for the sections either side of Stratford, suggesting that they are not among the steepest on the line. This 2017 thread is also worth a read, although it doesn't answer the question either. In a 2012 post mrfs42 estimated the gradients at Stratford to be about 1 in 31, and that thread also contains gradients (estimated and confirmed) for a few other points on the network In 2019 TfL refused a freedom of information request for gradients and speed limit data for the Central line. tubeprune notes on his website that (at least as of 2003) the steepest gradient on LU is 1 in 28 or 3.57% - between Bow Road and Bromley By Bow, District Line. I would have thought the gradient at Bow Road is one of the steepest. My father used to drive trains up it and said he never noticed any difference, or strain, on the motors. |
|
|
|
Post by jimbo on Nov 24, 2022 19:51:30 GMT
Acton Town back into Ealing Depot is the same as east of Bow Road, so surface stock tests for starting on a gradient were done there instead.
|
|
|
|
Post by d7666 on Nov 24, 2022 20:57:29 GMT
I have some data on some of this.
Central going west after Stratford station is 1:31 down for ~150 m then 1:50 down for another ~500 m
The same diagram set has short 1:25 twixt Holborn and TCR and again Notting Hill Gate and Holland Park; and on the Northern 1:24 between Borough and E&C; all of these sections are less than 100 m long _ having said that, gradients of that order are significant even when short.
|
|
|
|
Post by d7666 on Nov 24, 2022 21:30:54 GMT
tubeprune notes on his website that (at least as of 2003) the steepest gradient on LU is 1 in 28 or 3.57% - between Bow Road and Bromley By Bow, District Line. hmmmmm .... that data source I have shows that as 1:38/1:39 not 1:28; I am not going to get into a who is right or wrong here, but I am looking at it right now, and it shows about 200 m 1:38 + 200 m 1:39. |
|
|
|
Post by stapler on Nov 25, 2022 16:18:29 GMT
I have been consulting "Improving London's Transport" the Railway Gazette supplement of May 1946. There is a description of the Loughton Branch Junction signalbox consolidation (with intriguing photo) on p24. The gradient east of Stratford is, annoyingly, not stated, but approaching Stratford from Mile End is given from Carpenders Rd, as only 1 in 45. (p.21).
It would have been known that the Standard Stock, with which the line opened, had coped easily with the 1 in 20s of the CLR, but these were for acceleration/deceleration.
|
|
|
|
Post by stapler on Nov 25, 2022 16:57:31 GMT
tubeprune notes on his website that (at least as of 2003) the steepest gradient on LU is 1 in 28 or 3.57% - between Bow Road and Bromley By Bow, District Line. How did they cope with that under steam traction for the first 5 years of the Whitechapel & Bow - and from a standing start?! |
|
|
|
Post by d7666 on Nov 25, 2022 22:28:04 GMT
tubeprune notes on his website that (at least as of 2003) the steepest gradient on LU is 1 in 28 or 3.57% - between Bow Road and Bromley By Bow, District Line. How did they cope with that under steam traction for the first 5 years of the Whitechapel & Bow - and from a standing start?! I can only comment as I posted just above the data I have shows that as 1:38/1:39 not 1:28. Repeat I can't further comment which is correct, only relay the data I have from current source. |
|
|
|
Post by d7666 on Nov 25, 2022 22:36:30 GMT
I have been consulting "Improving London's Transport" the Railway Gazette supplement of May 1946. There is a description of the Loughton Branch Junction signalbox consolidation (with intriguing photo) on p24. The gradient east of Stratford is, annoyingly, not stated, but approaching Stratford from Mile End is given from Carpenders Rd, as only 1 in 45. (p.21). It would have been known that the Standard Stock, with which the line opened, had coped easily with the 1 in 20s of the CLR, but these were for acceleration/deceleration. The same data set I refer to, for eastbound Central, shows a mix of upgrades to 1:56 from Mile End before a last 1:46 for the final ~300 m into platforms, then 1:30 fall east of platforms for about ~300 m then shallower values. There appear to be no signifcant grades further east. But I can't go on and on and answer this for every station though. As far as I can see from the data set, I have posted the steepest grades I can find anywhere. Where there are slight discrepancies in the data I have against published gen, other like 1:38 against 1:39, or 1:45 against 1:46, it is possible one value is the true grade the other a compensated grade; I can't say if this is right, it is just a guess. Where there are larger discrepancies I have no idea other than to suggest one or other have typos somewhere. I at least do have a source document that shows 1:38/1:39 for BromelyByBow <-> BowRoad. |
|
|
|
Post by d7666 on Dec 2, 2022 23:38:24 GMT
Back to the original question. Methinks in time the gradient data will appear. The ELRs (engineers line references) for Crossail / Eliz.line are east to west : LTN1 XRS / XRE XRC MLN1 Source = www.railwaycodes.org.uke.g. www.railwaycodes.org.uk/elrs/_mileages/x/xrc.shtmThis site does not do gradients but if you want to search this way is the best to find an ELR that you need here : This site : www.railwaydata.co.ukspecifically here : www.railwaydata.co.uk/linefiles/to find gradients; there is a station search box however I have found sometimes this might not give you the answer you want if you don't input the precise search term and some of those terms are not intuitive, which is why going via the ELR code sometimes works better. Unfortunately, so far, none of the XR codes are available, but predict they will be in time as the site is maintained. |
|
|
|
Post by joshua on Feb 4, 2023 16:23:39 GMT
This 2015 post by North End has some figures for the Central line, but not for the sections either side of Stratford, suggesting that they are not among the steepest on the line. This 2017 thread is also worth a read, although it doesn't answer the question either. In a 2012 post mrfs42 estimated the gradients at Stratford to be about 1 in 31, and that thread also contains gradients (estimated and confirmed) for a few other points on the network In 2019 TfL refused a freedom of information request for gradients and speed limit data for the Central line. tubeprune notes on his website that (at least as of 2003) the steepest gradient on LU is 1 in 28 or 3.57% - between Bow Road and Bromley By Bow, District Line. How is it any issue for TfL lines for the gradient profile and top speed limits to public, when the maximum speed limits and gradient profile for Network Rail lines is public? |
|
