I've a vague recollection of Virgin changing from front to rear pan on the 390s about 8 years ago and someone saying it actually gave an alert drive just enough extra time to drop the pan and coast if there was a visible OHLE fault. No one mentioned the aerodynamics of the pan for direction of travel. OTOH I may have been dreaming.
Have a look for photos of Class 91s - there's often a distinctive swoop of black dust on the sides, particularly noticeable on the Virgin livery.Never heard of either of these before. Indeed never heard of pantograph dust spraying a train!
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Have a look for photos of Class 91s - there's often a distinctive swoop of black dust on the sides, particularly noticeable on the Virgin livery.
Here is a good shot of the two-car Class 309 post-refurbishment (and now a four-car). In this form the vehicle was a DMBSO but as built it was a DMBSK seating 48 second in six compartments plus a toilet immediately behind the first passenger door (the half-width window in the picture). After refurbishment as well as the compartments being opened out the toilet was removed to seat 52. You can just make out the higher secondary roof guttering for the toilet water tank overflow to direct any overflow water away from the passenger door where it could overwhelm the normal rain guttering.
https://www.simsig.co.uk/Media/Wiki/usertrack/ttuse/8827915_orig.jpg
The extra vehicles were converted from loco-hauled Mark 1s, both to extend the 2-car sets to 4-car and to replace the catering vehicles that were in some of the 4-car sets.Not to go too off topic in my own thread but I'm curious how these conversions to 4-car were done. I don't imagine there were a load of half sets or spare trailers sitting around. Were some driving cars or regular loco-hauled coaches converted to trailers?
I've noticed in some countries, especially Japan many Emus seem to have pantographs, almost every other carriage.... Is there some fundamental technology difference that mandates this? Always seems really odd
I've noticed in some countries, especially Japan many Emus seem to have pantographs, almost every other carriage.... Is there some fundamental technology difference that mandates this? Always seems really odd
Not quite- an original (0 Series) Shinkansen was 12 carriages with 6 pantographs, and all varient formations ran with that ratio throught their service life. The 100 series were then built at first with 5 pantographs in a 13 car set (later lengthened to 16), then 6 in a 16 car set (these were reduced to 3 pantographs in the 90s), and the later examples of the series were simply built with three pantographs for the 16 car set.Its historical, rather than using auto transformers they started off using booster transformers, however when the power demands grew (and especielly with introduction of Shinkansen) they had a lot of trouble with wild voltage fluctuations and discharges so they switched to the European AT system. So the Shinkansen started off with 8 carriages each having their own pantograph but switched in the early 80’s to 2 pantographs being raised and having a bus between the carriages. To maintain compatability with wires and good electrical contact the two remaining pantographs exert the same upward force on the wires as the 8 originally did, 54 N.
To get around the bridging issue they have changeover sections, these are short sections of neutral which can be energised from either side, when it detects a train approaching it will switch the neutral section to being fed from the opposite side until the train has passed through with an air gap to prevent bridging back into the section the train has come from.
And none of that is to do with DC- the Shinkansen network is 25kV AC 50Hz.
One 123 DMU trailer buffet was used late 60's early 70's to replace a damaged griddle carA 10-car formation of class 309s, arriving at Colchester in August 1964; the twin-set is at the front:
View attachment 57216
When refurbished and converted to 4-car sets, using a class 123 trailer as an intermediate vehicle was considered, but I can't remember if this was actually carried through.
I think the coaches that extended the 2-car 309/1s were ex-LHCS, and they came with B4 bogies rather than the 309's native modified Commonwealth type.A 10-car formation of class 309s, arriving at Colchester in August 1964; the twin-set is at the front:
View attachment 57216
When refurbished and converted to 4-car sets, using a class 123 trailer as an intermediate vehicle was considered, but I can't remember if this was actually carried through.
Yes I remember it clearly. ISTR that it had loose chairs rather than the 2+1 (rather comfy) seating of the original 616? - that rings a bell.One 123 DMU trailer buffet was used late 60's early 70's to replace a damaged griddle car
Not quite- an original (0 Series) Shinkansen was 12 carriages with 6 pantographs, and all varient formations ran with that ratio throught their service life. The 100 series were then built at first with 5 pantographs in a 13 car set (later lengthened to 16), then 6 in a 16 car set (these were reduced to 3 pantographs in the 90s), and the later examples of the series were simply built with three pantographs for the 16 car set.
I also remember reading that the APT was built with the power cars in the middle as the OHLE north of weaver junction has been done on the cheap and could not cope with two pantos up at speed.
It’s more that the OLE anywhere (pre GW electrification) can’t cope with 2 pantographs up above 100mph. And the problem is worse the further apart the pantographs are.
That's an interesting fact when you consider one of the arguments for OLE over third rail is that rail cannot be effectively used above 100mph.
It’s really about inadequate infrastructure in this country.One of the lesser arguments, and it’s not just about contact but also power draw.
It’s more that the OLE anywhere (pre GW electrification) can’t cope with 2 pantographs up above 100mph. And the problem is worse the further apart the pantographs are.
Other way round - the closer the spacing the worse it is. IEPs are subject to speed restrictions when running in multiple with the pans up at any configuration other than the extremity of the pair of sets.It’s more that the OLE anywhere (pre GW electrification) can’t cope with 2 pantographs up above 100mph. And the problem is worse the further apart the pantographs are.
It’s really about inadequate infrastructure in this country.
Having seen a four loco “Re20/20” (Re6/6+Re4/4+Re6/6+Re4/4) in Switzerland last year, all pan up and if they so wished a power rating of 25MW (33,500hp), it did rather reinforce just how poor this country is at electrification.
Umm, HS1 copes quite well with 2 pans up at 125 mph+ (Javelins) & 180 mph E-Stars.
The OHLE (Standard French Hi-Speed) seems to be quite simple, with closer mast spacing than elsewhere in the UK, but simple catenary.
It was an extreme - and rather impressive - example. But we can’t even run a pair of Class 90s through hilly areas (Shap and Beattock) when we need to without isolating traction motors as the infrastructure can’t take the power draw. It’s pathetic.If there was a need to run very high power traction to haul heavy trains through a mountain area, and we had all energy from hydro projects, it would be easy to provide the infrastructurenecessary for them to operate.
350s can run in multiple at 110mph on the WCML I think, though I'm not sure if they can do so north of Weaver Junction (towards Preston and Glasgow) on the less robust OLE installed in the 70s.It’s more that the OLE anywhere (pre GW electrification) can’t cope with 2 pantographs up above 100mph. And the problem is worse the further apart the pantographs are.
The WCML between London, Liverpool and Manchester was electrified with compound catenary too, possibly excepting some lower-speed sections. The fast lines were upgraded to simple catenary in the WCML modernisation but I think some remains. For example, from the RAIB report into electric shock at Sutton Weaver in 2014:And the tension is quite high which means that standing waves are of lower amplitude and of shorter wavelength. Simple catenary haas been the standard in the UK since the '60s. The lines converted from 1500VDC, e.g. GEML, had compound catenary OLE as it was thought to dampen pantograph oscillations, which at the time of introduction were much heavier diamond pattern types. The additional wire in compound also helped to reduce voltage losses. The last compound wiring was removed a few years ago when the GEML OLE was refurbished with F&F parts, similar to those used on the GWML.
Here is a picture of Ilford station, probably in the '90s when 25kV had been in use for over 30 years. Note the compound catenary:
The OLE in this area is constructed to the design known as Mark 1 (Mk 1) compound catenary and became operational on this line in 1962. Unlike more recent designs, which use just two wires running above each track, this design uses three.
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Network Rail has informed the RAIB that approximately 6% of its OLE on the London North Western route (LNW) has Mk 1 compound catenary (in terms of track miles).
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There had been plans to replace the remaining sections of Mk 1 compound OLE, including Sutton Weaver, in 2007. The estimated cost for this project was £30 million and it was not progressed due to a weak business case based upon the small cost savings from reducing train delays by increasing the reliability of the OLE.
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Network Rail LNW has identified 28 single track miles of its infrastructure where Mk 1 compound OLE could, if it fails, come into close or actual contact with members of the public, eg adjacent to station platforms. It has told the RAIB that it plans to request investment authority to remove the auxiliary wires in these sections so that this can be completed by April 2016.