Xenophon PCDGS
Veteran Member
Is it me or is this thread getting way, way off the subject?![]()
I fear that you have indeed highlighted a most valid point.
Is it me or is this thread getting way, way off the subject?![]()
They haven't decamped because the argument worked.
They haven't been given any reason to go anywhere else.
But you can guarantee that they would.
The market values nothing but expediency.
let focus on Northern Rail and the possibility of getting more EMUs
Why not ? Why not also supplement these stocks with "cascaded" stocks from other areas once these other areas have received their new stock.
Perhaps you will now understand the animosity to certain "favoured" areas by those deemed to be "second-class" areas...
The words "goose" and "gander" seem to ring extremely loud bells in these "second-class" areas.
On another thread, I TWICE made the very point of stating that I felt the Class 150 units would be an ideal mode form of rail traction on the soon to start Blackburn-Copy Pit line- Manchester Victoria service, but was informed TWICE that only Class 142 Pacers were the right class to operate this particular brand new service and that asking for the class 150 units that you refer to in your posting which were needed elsewhere would be at the cost of not improving services that serve the South Yorkshire and Lincolnshire areas of the Northern Rail current franchise.
I think my answer to this question is to turn it on its head:
"Why does the North want/need new trains?"
Once you step away from the "Well, it would just be nice, and it's unfair that we don't get them" and look at the issues afflicting rail travel in the North, there are some important facts to consider.
1. We requre additional capacity:
This can be addressed with longer/more frequent trains. Their "newness" doesn't necessarily come into it. Given current service levels, the existing infrastructure should largely be able to support longer trains and more paths.
2. We wish for cleaner, more modern trains:
A decent refurbishment of existing stock can fulfil most of these requirements. In many ways, the PRM-TSI legislation is good for all rail travellers, as it will insist upon a base-level of amenities, such as large, accessible lavatories and passenger information systems et al.
3. We wish for faster services:
This is far more likely to come down to line speeds. What use is a fast train if the linespeeds mean it doesn't even reach 75mph for large portions of the route. Line upgrades are far more useful here. Even the humble 150 could provide improved service if the lines it runs on are upgraded to allow more 75mph running
That's a good way of looking at it.
"The North" has a lot of lines where the current services get nowhere near 75mph and where a 40/46m DMU copes fine with demand (I think it was WatcherZero who pointed out that Northern services have an average passenger load of something like 45 people?)...
...so its hard to see the justification for lots of brand new 100mph four coach units. If anything, cascaded stock like the 317s or 319s are going to be over-kill on the routes they may operate.
I've suggested three coach 90mph EMUs (the 318s and 320s from the Glasgow area) which would generally be a step forward from a Pacer/ 150/ 156 (and easier to double up to six coaches)
Based on the current Northern franchise plus the Manchester Airport - Blackpool TPE service (which might as well be part of Northern...) I can see them needing around a hundred EMUs by the time CP5 is finished with.
Coincidently, that works out at all of the 333s and all of the 319s (323s move to LM, 321s and 322s to GA).
While the 319s will undoubtedly be an improvement on Pacers and Sprinters, I fear passengers accustomed to the 323s would regard their replacement by 319s as a step backwards, particularly in respect of the inferior acceleration and greater susceptibility to leaves on the line.I see that a number of my postings have brought forward well-crafted technical posting replies. I will hold up my hands and admit to having Class 323 units on our local Macclesfield area services and not the types of arcane DMU that cause certain posters who have accept such units for their mode of local travel. As such, I now feel somewhat obliged to apologise to those forum members for having to suffer from their particular modes of DMU travel and I am indeed thankful for the Class 323 units made available to us by Northern Rail in our part of Cheshire East.
319s might be particularly ill-suited to the Glossop/Hadfield line, with its closely-spaced stations and steepish gradients.
Even then the acceleration wouldn't match the 323. Acceleration depends a lot on the number of motored axles, a 3-car 319 would still only have one third and a 323 has two thirds. A 319 also has less power and DC motors are probably less effective at using this power at high speeds. A re-tractioning might address these two issues but would be unlikely to add another power car in each unit.
319s have DC Traction on four axles with chopper control, chopper control is nearly the most modern DC traction control available, but DC motors are not ideal, especially in the mid end.
323s have Single Source Excitation GTO Thyristor Controlled 3 Phase AC Motors on 8 axles, not only is this motoring on more axles, it incorporates (if I'm thinking right from what I know of Hunslet's control equipment) variable winding controls and by the very virtue of AC traction, very good wheel slip protection and traction control.
Even if the 319s are refurbished with IGBT invertors on the currently motored axles with AC motors, they won't be as powerful, nor will you have as much tractive effort at the low end because you simply have many less points of contact with the track.
As explained in the above posts, a 319 inevitably has worse acceleration than a 323, especially in conditions of poor wheel/rail adhesion.Take it you haven't been on the Thameslink Core with some of the steepest gradients on the UK network (something like 2nd or 3rd in the country) and extremely close stations then?
319s have worked on that sort of environment since day one.
While the 319s will undoubtedly be an improvement on Pacers and Sprinters, I fear passengers accustomed to the 323s would regard their replacement by 319s as a step backwards, particularly in respect of the inferior acceleration and greater susceptibility to leaves on the line.
319s might be particularly ill-suited to the Glossop/Hadfield line, with its closely-spaced stations and steepish gradients.
The vast majority of commuters won't notice such technical issues.
No, but they will notice if their journey takes longer because the timetable has to be changed. The Glossop/Hadfield line already has a special autumn "leaves on the line" timetable, despite the 323s having 8 powered axles and wheel slip protection. I doubt that leaves or snow are often much of a problem in the Thameslink tunnels.The vast majority of commuters won't notice such technical issues.
Take it you haven't been on the Thameslink Core with some of the steepest gradients on the UK network (something like 2nd or 3rd in the country) and extremely close stations then?
The vast majority of commuters won't notice such technical issues.
How would the acceleration of a 319 with AC motors compare to that of a 323?
How would the acceleration of a 319 with AC motors compare to that of a 323?
And a maximum speed of, what, 20mph?
Used to be 40mph prior to the rebuilding. But that not the point I was replying to. Other poster was stating that close together stations and steep gradients may make the 319s unsuitable and I was pointing out that what they have been doing for every day for the last 25yrs.
The steepest gradients are either side of City Thameslink where the speeds may be lower and attainable speed is lower still. My point is that climbing a gradient at low speed needs less tractive effort or power than accelerating up it or climbing it at higher speeds.
The tractive effort required to ascend the slope is largely the same for most reasonable speeds (obviously not including air resistance which is a fairly minor problem at the speeds that the Glossop and Hadfield line works at).
However you are correct that Power, Power, Power is what is important for climbing gradients.
323s have been terrible for wheelslip since the day they entered service! The stats may say its "inevitable" but the reality is somewhat different. There is a reason the x-city has one of the most trimmed leaf fall services in the country and its largely 323 related.As explained in the above posts, a 319 inevitably has worse acceleration than a 323, especially in conditions of poor wheel/rail adhesion.
Quite. I was not suggesting that the 319 would be unable to climb the gradients on the Glossop/Hadfield line, merely that it might not be able to maintain the same timings as the 323, particularly in slippery conditions. Network Rail is investing in linespeed improvements on this line in CP5, with the objective of increasing capacity by enabling an increase in frequency, and thereby avoiding the need for platform lengthening beyond the current 3x23m car length. It would not be very joined-up planning then to undermine this strategy by replacing the 323s, which have operated in this area all their lives, by older 4x20m 319s with worse power-weight ratio, just in the interests of national fleet rationalisation.The tractive effort required to ascend the slope is largely the same for most reasonable speeds (obviously not including air resistance which is a fairly minor problem at the speeds that the Glossop and Hadfield line works at).
However you are correct that Power, Power, Power is what is important for climbing gradients.