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| DVT failures and non working TDM. 20/01/2019 at 11:56 #114926 | |
jc92
3690 posts |
I thought I'd put this question on here in the hope of some thoughts or information. I am currently working on Man Pic 1992 and wondering about the best way to work the Euston trains. Almost all sets are booked as push pull with a DVT, however I am aware in practice some locos either hadn't yet had TDM fitted (rare at this point) or it was faulty or the DVT may have failed resulting in some trains still running loco first with a change of loco at manchester/liverpool/Birmingham etc. First question: would planning have been aware in advance of this and issue any sort of advance notice to staff as to which train would require a loco swap or would it have been an on the day thing. Second question: I can either prebook certain trains to change loco (which is how Stockport trains are currently done) or I can add a decision to each train with a small weighting to produce random TDM failures requiring a loco change. This would also require relevant duplicate up trains and decisions on stockport for chaining purposes. Which do people think is more representative? "We don't stop camborne wednesdays" Log in to reply |
| DVT failures and non working TDM. 20/01/2019 at 12:23 #114928 | |
Noisynoel
989 posts |
Ok, so in answer to your 1st question, the moves would probably have been identifed overnight when loco's were allocated to diagrams, they almost certainly wouldn't have been planned any further out than that. Secondly, I think using the decisions option makes the timetable far more interesting as each time it's going to be different.
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| DVT failures and non working TDM. 20/01/2019 at 17:54 #114940 | |
58050
2659 posts 
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TDM or (Time Division Multiples) was first used on the Scotrail services between Glasgow Queen Street & Edinburgh Waverley. When those services were replaced by Sprinter units in the 1990s the DBSO(Driver Brake Second Open) were transferred to the Anglia Region to work on the Norwich - Liverpool Street - Norwich inter City services & subsequently on the WCML. Now this reduced the number of locos required to cover diagrams as the loco would either pull or push the consist along. On the Anglia Region the DBSOs had an achilles heel which was the TDM & this could fail quite often resulting in the need for diesel to haul the train in the conventional manner. Obviously none of us in the Regional Control could plan when a failure was to occur & bear in mind that when the loco was hauling the train in the conventional manner TDM wasn't required & as a result the train wouldn't fail unlss the eletric loco on the front developed a fault. Both Inter-City sets on Anglia & the WCML had similar formations in so much as the DBSO or DVT)Driver Van Trailer) was at the rear of the train departing from London, but when the train was running from the north heading to London the DVT or DBSO would be leading. Only in exceptional circumstances did that changes due to the train being diverted of its booked route. Now as time went by the TDM was improved & it became more & more reliable so by 1993 for example the problem was almost gone. The main problem was that when the driver opened the desk in the DBSO the TDM was lost somewhere along the train & as a result the loco wouldn't respond to the drivers commnads hence the usual request for a diesel to Liverpool Street off Stratford TMD to drag the train through to Harwich or Norwich with the eletric dead in tow. DVT failures on the WCML were evn rarer as by the time they were introduced all the stumbling blocks of the older variations of TDM had been ironed out. If you are thinking of adding in a failuire option regarding DVTs then this would only apply on UP trains from Piccadilly & even then you'd be lucky if you ot 1 in a week. If you were writing a GE timetable for the GE mainline I'd say the chances of a TDM failure would be alot higher to the point where you'd get possibly one a day, but surprisingly enough it was always the same loco or set that developed a fault & it wasn't down to the loco it was down to the TDM. 86232 is one that sticks in my mind during the early 1990s as that loco was regualrly on a set where the TDM failed somewhere en route & had to be assisted by a diesel. Now back in the days of sectorisation which is what jc92 tt is based on an assisting diesel wouldn't be used as that would incur charges, so the electric loco would detach off the rear & re-join the train on the front. Another thing only BR personnel wilkkl be aware of is that a train with a DVT/DBSO on the front can run at maximum speed with the driver is the rear locomotive & the guard sitting in the drivers seat of the DVT/DBSO CAN run at linespeed PROVIDING there is clear communication between the guard & driver. So if the TDM fails in the middle of nowhere for example then the guard would sit in the drivers seat of the DVT/DBSO(Guards also have to sign the route just like drivers) & the driver would climb into the cab of the loco at the back of the train & the train would continue to a point designated by Regional Control where the loco would run round & the train would continue with the loco leading. personally I don't think I would bother with your suggestion Joe as it happened so rarely. Hiring diesels off freight sectors would cost between £600-£1000, plus another £600 for the driver of the assisting loco(1990s money & in the era of privatisation clearance of the line was a mandatory £2000 fee, hence the reason why Virgin for example got the Cl.57 'Thunderbirds' so they wouldn't have to pay for the hire of other companies assests to rescue one of their failed trains. That principal started during the 1990s with sectorisation so the use of freight sector locos on passenger trains deminished as eacj year went by. I've got a handful of vivid memories of dispatching locos off Stratford TMD to rescue failed Inter-City trains with TDM faults:- 37055 worked from Stratford to Norwich on the 1830. Liv St. - Norwich all the way to Norwich 37242 worked the Down Anglian from Liv ST. - Norwqich but failed at Witham in spectacular fasion by loosing all it's coolant. The bashers on it enjoyed the thrash as it maintained Cl.86 timings to that point & then completely destroyed the rest of the evenings services. 47572 'Ely Cathedral' was the last Cl.47/4 to have a CEM at Stratford DRS & for it's first working back on the mainline by working an Inter-City service from Liv St. to Harwich. Happy days. Log in to reply The following users said thank you: jc92, BarryM, ajax103 |
| DVT failures and non working TDM. 21/01/2019 at 13:25 #114954 | |
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47417
13 posts |
In the 1992 era, the West Coast Regional Control based at Crewe had two Locomotive Controllers that managed the Intercity West Coast (IWC) electric locos (geographical areas of responsibility were south of Stafford (incl) and north of Stafford (excl). Also a Stock Controller who managed all the IWC rolling stock based at WB/OY/MA/PC. In consultation with these depots (and other overnight stabling locations EN/PN/HD/CL/LL) through the West Coast Shift Maintenance Engineer, also based in the West Coast Control, details would be compiled of any sets or locomotives that were to be 'TC' restricted (non-TDM operation). At the start of each day - around 03:30 - a message - referred to as a 'wire' - would be sent out to all points on the WCML listing all trains that were currently known to be operating non-TDM that day. This first non-TDM wire of the day would be 'Wire No.1' and each subsequent wire would be numbered to ensure that none were missed by the receivers. Non-TDM operation was a daily occurrence and it wasn't often at this time that all services would be operating in TDM mode from the start of service. The Locomotive Controllers were then responsible to liaise with the respective Area Controls (AOC), Yard Supervisors & TCS to manage the additional loco movements required for Non-TDM working. Trains could be returned to TDM operation in the middle of the diagram after a defective loco had been replaced or a successful TDM test had been undertaken where time permitted (normally at Euston). Also there were various contingency plans in place to cover non-TDM operation in the winter when certain types/depth of snow was forecasted. More generally this mainly affected just Anglo-Scots but on a bad forecast day we operated the whole route non-TDM. This latter scenario resulted in train cancellations as the resources just weren't there by this time to run all services non-TDM. This adverse weather operation for snow was brought about due to the passage of the train disturbing the lying snow which then resulted in it entering the air intakes on the loco at the rear and getting into the traction motors resulting in the locomotive failing - was particularly prevalent on Class 90s. With regards to propelling the train with the Driver in the rear driving the loco and the Guard in the DVT at the front, this would have only been undertaken to clear the line at reduced speed and never at line speed. In this era auxillary compressors had not yet been fitted to DVT's and as a result due to main reservoir protection issues DVT operated trains were not allowed to be assisted in the rear by any following services (except light engines of course). This propelling practice was ceased on ICWC after one dark winters evening during a points failure at Wembley a non-TDM train was setting back with the Guard in the DVT cab and passed a GPLS at danger by some considerable distance. Remember that even though Guards sign the route, they do not necessarily know (nor are they required to) the location of signals, especially in unusual movements such as this. Last edited: 21/01/2019 at 13:50 by 47417 Reason: None given Log in to reply The following users said thank you: jc92, BarryM, ajax103 |
| DVT failures and non working TDM. 27/01/2019 at 09:20 #115094 | |
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TomOF
452 posts |
An excellent article in traction magazine a few years ago by a west coast driver explained that when first introduced, the TDM was prone to deconfiguring as the train passed the ILS equipment close to the runway threshold at Birmingham Airport. The equipment would fail safe and train would ground to a halt. This was quickly rectified in conjunction with the Airport authorities once the cause was realised. Other that that I wonder how much of a problem this would be for trains en route.
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| DVT failures and non working TDM. 28/01/2019 at 09:16 #115148 | |
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kbarber
1743 posts |
TomOF in post 115094 said:An excellent article in traction magazine a few years ago by a west coast driver explained that when first introduced, the TDM was prone to deconfiguring as the train passed the ILS equipment close to the runway threshold at Birmingham Airport. The equipment would fail safe and train would ground to a halt. This was quickly rectified in conjunction with the Airport authorities once the cause was realised. Other that that I wonder how much of a problem this would be for trains en route.Which reminds me of a story I heard about the early days of RETB on the East Suffolk line. (I wouldn't want to vouch too much for its accuracy, but heard it from a senior S&T bod I was chatting to when I was on a course; he was on another course at the same location and we'd discovered a common interest in bellringing, sufficient to get both of us out of our silos. He, in turn, had heard at least part of the story from a guard on his train.) They kept on having total system failures. But by the time the S&T arrived, everything was working perfectly. Eventually they established that there was massive interference with the radio signals that was wiping the entire system off the air. Further research linked it with the local USAF base (Bentwaters?). It turned out that, as their jets rolled down the runway to go off on exercise, they turned on their Electronic Counter Measure gear and splattered everything else for miles around, including the RETB. Eventually an agreement was reached that ECM would not be activated until planes were well out at sea, and normality returned. But there was a caveat: if the balloon went up, all bets were off. So, in a broad Suffolk accent, my informant was advised "if you down 'ere and you can't get a train, run and 'ide!" Log in to reply The following users said thank you: GeoffM, BarryM |
| DVT failures and non working TDM. 28/01/2019 at 10:47 #115152 | |
postal
5265 posts |
kbarber in post 115148 said:It turned out that, as their jets rolled down the runway to go off on exercise, they turned on their Electronic Counter Measure gear and splattered everything else for miles around, including the RETB.Their is a similarly apocryphal tale about the constable standing beside the A1 near Berwick with the kit in hand for clocking speeding motorists who was extremely lucky that the incoming pilot of the Tornado on its way to the nearby Otterburn ranges manually intervened to stop one of its missiles taking out the enemy radar. “In life, there is always someone out there, who won’t like you, for whatever reason, don’t let the insecurities in their lives affect yours.” – Rashida Rowe Log in to reply The following user said thank you: GeoffM |
| DVT failures and non working TDM. 10/02/2019 at 14:20 #115520 | |
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bill_gensheet
1414 posts |
>> TDM or (Time Division Multiplex) was first used on the Scotrail services between Glasgow Queen Street & Edinburgh Waverley. When those services were replaced by Sprinter units in the 1990s the DBSO(Driver Brake Second Open) were transferred to the Anglia Region to work on the Norwich - Liverpool Street - Norwich inter City services & subsequently on the WCML << Some minor corrections / clarifications. Anglia did not run DBSO with 47's in DBSO mode, the DBSO only came along after it was through 86's. The 47/7 went to NSE without the DBSO's. The Mk3 DVT were new to WCML roughly alongside the Class 90's. WCML never had Mk2 DBSO's as they stayed on Anglia for a lot longer. Anglia eventually went Mk3 DVT when they were spare and Mk3 sets came over - so around Class 390 introduction. Anglia always has the electric at the London end due to neutral section locations, otherwise it would have been a lot simpler as things would have failed at Norwich instead of Liverpool St. Bill Log in to reply |
| DVT failures and non working TDM. 10/02/2019 at 14:55 #115521 | |
ajax103
1120 posts |
bill_gensheet in post 115520 said:>>I thought the reason they had the Class 90 at the London end was simply because of the layout at Norwich, it was easier to swap locos to/from Crown Point then it was if the loco was at the country end of any set. Unlike on the East Coast Mainline where the loco is always at the country end unless it gets turned at Newcastle. Log in to reply |
| DVT failures and non working TDM. 10/02/2019 at 20:21 #115532 | |
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bill_gensheet
1414 posts |
That could well be another reason, but Manningtree neutral was a problem with 'front hauled' down trains. Even now they noticeably slow and just get enough momentum to make it back onto the live out on the viaduct.
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