The Great HST Cascade?

[David10]

I don't think Alstom can build the Class 175 anymore.

Having been designed nearly 15 years ago, it is unlikely that the 175s would comply with current crash requirements.

 

[swt_passenger]

That doesn't matter. If the order was big enough then they would happily build it. People need to stop thinking that destroyed jigs is a show stopper. It only is if you're looking at adding a few dozen vehicles to a fleet where the jigs have been destroyed. If you wanted to add several hundred there would be no issue.

I'd agree entirely. Besides which, production engineers are not in the business of 'destroying' jigs. What is far more cost effective is that at the end of a particular production run they adapt the details of what is basically a general purpose framework to fit whatever they build next. In principle this would be reversible once an order was complete.

The idea is that the 'jigs' are robust handling and alignment aids that are used to join big sections with one another accurately - robbies' idea of 'plates ... for the moulds' implies something completely different...

 

[tbtc]

40 new Class 175 trains would be ordered (if it is still possible to do this)

I don't believe that Alstom have the plates anymore for the moulds of the Class 175 and I think the order would be too small for them

There were only twenty seven 175s ordered/built in the first place, so an order of forty is pretty big in comparison.

Whilst I don't have the blank cheque to sign it off, I do like ryan125hst 's plan of getting in some 75mph DMUs as these will be what's needed on some Northern lines (electrification won't cascade enough DMUs, 158s are unsuitable for frequent stopping services, few Northern services are in danger of requiring speeds of over 75mph, slower top speed should mean better acceleration on a DMU).

 

[Nym]

So... Just order some Class 172 units then?

 

[Drsatan]

So... Just order some Class 172 units then?

Possibly, although the 172s, being a derivative of the class 170s, have a design dating back to the late 1990s. I'm also not sure whether they'd be able to keep to time on services booked for 150s and 153s since they accelerate more slowly.

If this order for new DMUs for Northern ever goes ahead (which looks extremely unlikely), I'd suggest ordering a new design.

 

[sprinterguy]

Possibly, although the 172s, being a derivative of the class 170s, have a design dating back to the late 1990s. I'm also not sure whether they'd be able to keep to time on services booked for 150s and 153s since they accelerate more slowly.

I'm not aware that the schedules on the Snow Hill lines have been decelerated since the 172s took over, and those services cover a very intensive start-stop set of routes that were previously worked by 150s and a small number of 153s. They don't seem any slower to accelerate and cover station to station distances than the 150s to me.

If this order for new DMUs for Northern ever goes ahead (which looks extremely unlikely), I'd suggest ordering a new design.

The class 172 design would seem to have bedded in well now after it's initial protracted teething troubles, and there would be far fewer design and development costs attached to introducing further 172s because they are a current, "off the shelf" design.

 

[Drsatan]

I'm not aware that the schedules on the Snow Hill lines have been decelerated since the 172s took over, and those services cover a very intensive start-stop set of routes that were previously worked by 150s and a small number of 153s. They don't seem any slower to accelerate and cover station to station distances than the 150s to me.


The class 172 design would seem to have bedded in well now after it's initial protracted teething troubles, and there would be far fewer design and development costs attached to introducing further 172s because they are a current, "off the shelf" design.

Ok, I made that point after hearing that 172s cannot accelerate as quickly as 150s and 153s due to their added wait. Maybe the timetables you describe have significant amounts of padding?

To an extent I agree with you that the 172 is a tried and tested design, but in the long term I don't believe that Bombardier should continue to produce EMU and DMU designs that are now obsolete solely because there is no national rollingstock procurement/cascade program. With regards to a new design, one design I'd suggest is this

 

[CC 72100]

To an extent I agree with you that the 172 is a tried and tested design, but in the long term I don't believe that Bombardier should continue to produce EMU and DMU designs that are now obsolete solely because there is no national rollingstock procurement/cascade program. With regards to a new design, one design I'd suggest is this

Surely you would want something with corridor connections though - given the type of work they would do and the fact that they would not travel at particularly high speed.

The simple fact of the matter is that new DMUs will be required. We just need to decide what to order, where they should go, and what should be cascaded.

And then where to send the redundant pacers

 

[Drsatan]

Surely you would want something with corridor connections though - given the type of work they would do and the fact that they would not travel at particularly high speed.

The simple fact of the matter is that new DMUs will be required. We just need to decide what to order, where they should go, and what should be cascaded.

And then where to send the redundant pacers

True, but then British railways seem to be virtually alone compared to other European railways, whom do not rely on MUs with corridor connections.

No new DMUs will be ordered for the foreseeable future due to the Northern Hub electrification (Euxton - Preston and Manchester to Liverpool). This is on the basis that enough 319s or 317s will be available to work these services (as it stands it looks unlikely that there will be enough 319s since nothing's been signed for the Thameslink contract).

And as for the Pacers, they will be consigned to Booths Metals of Rotherham since they won't be DDA compliant

 

[sprinterguy]

Ok, I made that point after hearing that 172s cannot accelerate as quickly as 150s and 153s due to their added wait. Maybe the timetables you describe have significant amounts of padding?

Nope, there's never been evidence of much hanging around at stations due to timetable padding on the Snow Hill lines, there isn't really the opportunity for it on a ten minute frequency (over the core section) suburban service. The Snow Hill lines act IMO as the perfect showcase route to demonstrate that Bombardier finally have cracked a commuter DMU design that is a worthy replacement for the Sprinters.
--- old post above --- --- new post below ---

To an extent I agree with you that the 172 is a tried and tested design, but in the long term I don't believe that Bombardier should continue to produce EMU and DMU designs that are now obsolete solely because there is no national rollingstock procurement/cascade program. With regards to a new design, one design I'd suggest is this

How do you consider that Bombardiers' DMU and EMU designs are "obsolete"? The Turbostar and Electrostar platforms have been updated to meet changing demands, culminating in the 172s and 378s/379s, which are markedly different to the original late nineties Turbostar and Electrostar designs. Although the Electrostar is set to be superceded by the Aventra in the future.

 

[tbtc]

Ok, I made that point after hearing that 172s cannot accelerate as quickly as 150s and 153s due to their added wait

The LM 172s are 100mph units - the 150/153s are 75mph units. Lower top speeds will generally mean better acceleration/ deceleration. Hence me banging on about getting more 75mph DMUs

The simple fact of the matter is that new DMUs will be required

No new DMUs will be ordered for the foreseeable future due to the Northern Hub electrification (Euxton - Preston and Manchester to Liverpool). This is on the basis that enough 319s or 317s will be available to work these services (as it stands it looks unlikely that there will be enough 319s since nothing's been signed for the Thameslink contract).

Electrification will not release the hundred plus units required to withdraw all Pacers (and half the 153s) by the end of the decade.

And some of the stock being replaced by electrification are the wrong sort to replace 142/143/144s (e.g. some of the HSTs from the GWML will be pretty much life expired by the time they are replaced by IEP, and not suitable on Pacer routes!).

Either we guarantee more "quick win" electrification (Valley Lines around Cardiff, GOBLIN, Calder Valley) or we bite the bullet and order some DMUs.

 

[LE Greys]

The LM 172s are 100mph units - the 150/153s are 75mph units. Lower top speeds will generally mean better acceleration/ deceleration. Hence me banging on about getting more 75mph DMUs

Now that's something I agree with. Even just changing the gear ratios on 172s (and calling them 172/2s or 173s or whatever) would be a good start. Really, though, we need to look for a 75mph Super Sprinter replacement before too long, with doors at the end, available as 1-car, 2-car or 3-car. Something nice and simple with modern engines and ideally the same transmission as the 172 to keep things compatible.

Electrification will not release the hundred plus units required to withdraw all Pacers (and half the 153s) by the end of the decade.

And some of the stock being replaced by electrification are the wrong sort to replace 142/143/144s (e.g. some of the HSTs from the GWML will be pretty much life expired by the time they are replaced by IEP, and not suitable on Pacer routes!).

Either we guarantee more "quick win" electrification (Valley Lines around Cardiff, GOBLIN, Calder Valley) or we bite the bullet and order some DMUs.

That sounds fairly accurate.

 

[sprinterguy]

Now that's something I agree with. Even just changing the gear ratios on 172s (and calling them 172/2s or 173s or whatever) would be a good start. Really, though, we need to look for a 75mph Super Sprinter replacement before too long, with doors at the end, available as 1-car, 2-car or 3-car. Something nice and simple with modern engines and ideally the same transmission as the 172 to keep things compatible.

London Overgrounds' 172/0s are already geared for a 75mph maximum (And the 172/2 sub-class is already in use with London Midland ).

Given that, in most cases, serious contemplation hasn't even been given to finding a suitable inner-suburban commuter unit to replace the vast swathes of Pacers and 150s currently used on those services, I don't think that replacement of the Super Sprinter fleet need be an immediate concern.

 

[LE Greys]

London Overgrounds' 172/0s are already geared for a 75mph maximum (And the 172/2 sub-class is already in use with London Midland ).

Bob's you're uncle and I'm a clot for not remembering that.

 

[HSTEd]

Well there is always the Harrogate Loop and D-stock concept.....

How many units does that displace?

 

[Wolfie]

Ok, I made that point after hearing that 172s cannot accelerate as quickly as 150s and 153s due to their added wait. Maybe the timetables you describe have significant amounts of padding?

To an extent I agree with you that the 172 is a tried and tested design, but in the long term I don't believe that Bombardier should continue to produce EMU and DMU designs that are now obsolete solely because there is no national rollingstock procurement/cascade program. With regards to a new design, one design I'd suggest is this

I am confused. You state that Bombardier are producing obsolete designs (despite an ongoing process of product development) and yet recommend a product that has design origins going back to at least the mid-90s (Alstom
acquired LBH, which designed the product, in 1996). Why, therefore, would that product be any less "obsolete" some 16 years later?