Replacement 20m DMUs - do we really need them and if so how many?

[Meerkat]

Triggered by reading the GWR thread and it seeming that two tinpot Cornish branchlines might be wagging the dog over what people think the GWR stock replacement spec would be.

1) Why have 20m units at all? I note that lots of EMUs, if not most, are 20m but I don't know why - more doors per set length or is it history, commuter land just being set up for multiples of that length?
2) Is a 2x20m DMU still practicable - ie will all the gubbins for a compliant engine etc fit (without catching fire etc..)?
3) Is it inevitable that Northern will need 2x20m DMUs - ie would going longer (eg new 195s replacing 150s) mean a massive infrastructure spend on platforms etc?

I guess I am asking as if Northern is inevitably going to order a stack of them its worth developing one for GWR, preferably a short version of their main buy (like SWR has 450 and 444 versions of the same thing). Otherwise the two problem branches should be adapted or binned!

 

[Bevan Price]

In the current economic situation - likely to persist for many years - I suspect it is more likely that at least some Class 150s will be made to last a lot longer than people might consider desirable.

 

[Snow1964]

The 150s are approaching 40 years old, how much longer they can be kept going remains to be seen.

Realistically there are a few branches around the country where choice is a new version to last until about 2070s, infrastructure upgrades, or line closure.

However if the solution is a pair of 20m cars, or a 3 part articulated unit with lower floor middle car and sections about 13-15m is debatable. Maybe a tram-train derivative.

 

[JonathanH]

The 150s are approaching 40 years old, how much longer they can be kept going remains to be seen.

To some extent they are easier to keep going than other units because they are fairly basic units with fewer unique or outdated parts than more modern units.

 

[edwin_m]

1) Why have 20m units at all? I note that lots of EMUs, if not most, are 20m but I don't know why - more doors per set length or is it history, commuter land just being set up for multiples of that length?

3) Is it inevitable that Northern will need 2x20m DMUs - ie would going longer (eg new 195s replacing 150s) mean a massive infrastructure spend on platforms etc?

There are lots of routes on the Southern that are only cleared for 20m stock, meaning a larger proportion of the total MU fleet spends at least some of its time on those routes. I believe that is a genuine restriction rather than simply that nobody has ever asked if clearance can be done easily. Away from the Southern there are very few with this sort of restriction - I don't believe there are any on the Northern network, but I stand to be corrected. Parts of the Valley Lines are restricted, but these now have their own bespoke rolling stock anyway.

In the 1980s EMUs of both systems, plus the 150, were based on a common bodyshell so all were 20m. When procurement was driven more by the Sectors, Regional Railways saw the advantage in buying longer vehicles rather than going with the standard BREL product. The 1990s saw a move back to standardisation on 20m for EMUs, mainly because the ROSCOs wanted a design they could operate across the electrified network including those Southern lines. 23m or thereabouts became the standard for DMUs, probably because there were so few non-electrified routes they could not run on. More recently, but rather off-topic, EMUs for anywhere north of London have adopted the longer bodyshell too.

 

[Meerkat]

However if the solution is a pair of 20m cars, or a 3 part articulated unit with lower floor middle car and sections about 13-15m is debatable.

Could you fit two engines and all the other gubbins underneath a 3 section train?

Away from the Southern there are very few with this sort of restriction - I don't believe there are any on the Northern network, but I stand to be corrected.

For northern I was thinking more in terms of platform lengths - sure there was discussion about 195s being too short, but too long in multiple???
Of course then someone has to do the numbers on how much work would need to be done versus how much would be saved by ditching 20m units.

 

[Irascible]

If platform lengths are the only consideration - instead of building with doors at 1/3ds, can we not build with doors at the inner ends & halfway down the body? that won't help if the route needs 20m bodies, obviously. Less than ideal for more commuter-ish routes but then should we really be building two car units for those these days?

 

[61653 HTAFC]

In most cases, extending platforms will be easier than trying to design a compliant diesel unit with 20m cars. At intermediate stations extending platforms is relatively simple, the problem is mostly at bays or termini where signals need to be relocated.

 

[JonathanH]

In most cases, extending platforms will be easier than trying to design a compliant diesel unit with 20m cars.

Maybe, but still an expensive project. That seems to be the three way conundrum on costs - keeping 150s going, extending platforms, building new units.

 

[Trainbike46]

Triggered by reading the GWR thread and it seeming that two tinpot Cornish branchlines might be wagging the dog over what people think the GWR stock replacement spec would be.

1) Why have 20m units at all? I note that lots of EMUs, if not most, are 20m but I don't know why - more doors per set length or is it history, commuter land just being set up for multiples of that length?

My understanding is that this is because 20m DMUs fit everywhere, whereas 23m, 24m or 26m units wouldn't; There is good reason to design a train that can be used across the cornish branches and GWR stoppers, and the exact coach length really isn't that important as long as it fits

2) Is a 2x20m DMU still practicable - ie will all the gubbins for a compliant engine etc fit (without catching fire etc..)?

Absolutely; recently build 20m(-ish) trimodes, bimodes and DEMUs are the 231, 755 and 756 classes; there is no reason manufacturers other than stadler couldn't build 20m(-ish) bimode units with level boarding and an easy pathway to be reconstructed into EMUs or battery EMUs later on when the mainline finally gets electrified

I guess I am asking as if Northern is inevitably going to order a stack of them its worth developing one for GWR, preferably a short version of their main buy (like SWR has 450 and 444 versions of the same thing). Otherwise the two problem branches should be adapted or binned!

I disagree here; design a pretty universal train that can go anywhere - you don't even need a new design if you go for a FLIRT - instead of insisting all the infrastructure gets changed; The trend in the southwest recently has been to open more branches, not close them. Closing lines because of an odd insistence on coaches being 23m instead of 20m is truly the tail wagging the dog

 

[Meerkat]

There is good reason to design a train that can be used across the cornish branches and GWR stoppers, and the exact coach length really isn't that important as long as it fits

There must be a reason all recent DMUs have been longer. And longer is better for regional trains.

Absolutely; recently build 20m(-ish) trimodes, bimodes and DEMUs are the 231, 755 and 756 classes; there is no reason manufacturers other than stadler couldn't build 20m(-ish) bimode units with level boarding and an easy pathway to be reconstructed into EMUs or battery EMUs later on when the mainline finally gets electrified

But if length is an issue then Stadlers with power pods aren’t a very good answer

Closing lines because of an odd insistence on coaches being 23m instead of 20m is truly the tail wagging the dog

It wouldn’t be the reason, more like the final straw……

 

[Grecian 1998]

There is no prospect of the Gunnislake branch closing as the primary reason it survived the 1960s cuts remains, namely the abysmal road access from the Bere peninsula into Plymouth. The Gunnislake - Callington section was closed because its road access was considered sufficient. AIUI the peak time numbers are large enough that a class 139 wouldn't be sufficient.

The line between Bere Alston and Gunnislake is best described as challenging for most rolling stock, as it's very steep and very twisty - it pretty much does a 180 degree turn just after Calstock.

 

[Class 317]

Surely the right answer to this question is none are needed.
Battery Electric Units are what should be being explored even if class 150's need to solder on for a few extra years.
Based on electric bus / coach technology they should be variable for light weight units for branch lines in the next few years.

 

[Meerkat]

There is no prospect of the Gunnislake branch closing as the primary reason it survived the 1960s cuts remains, namely the abysmal road access from the Bere peninsula into Plymouth. The Gunnislake - Callington section was closed because its road access was considered sufficient. AIUI the peak time numbers are large enough that a class 139 wouldn't be sufficient.

The line between Bere Alston and Gunnislake is best described as challenging for most rolling stock, as it's very steep and very twisty - it pretty much does a 180 degree turn just after Calstock.

Extend Bere Alston to Tavistock and drop the maniacally twisted bit to Gunnislake.

 

[Irascible]

Extend Bere Alston to Tavistock and drop the maniacally twisted bit to Gunnislake.

Please actually read. The reason the line is as it is, is because the roads are as they are. Swapping Gunnislake for Tavistock as a railway isn't going to change that.

 

[Ken H]

What is the impediment to keeping Cl150 going for a few decades for a niche on lightly used difficult branches?

Corrosion. Its steel - cant they be welded up?
Inadequate crash resiatance?
Bogies cant be life extended - buy new bogies.
Engine and power train cant be life extended or cant get parts - New modern engine and power train. Maybe even hybrid like a non plug in hybrid car.

So do a proper rebuild and deep refurb.
What would that cost against new units if you were to do a fair few of them?

 

[Meerkat]

Please actually read. The reason the line is as it is, is because the roads are as they are. Swapping Gunnislake for Tavistock as a railway isn't going to change that.

I did - particularly this bit....

the primary reason it survived the 1960s cuts remains, namely the abysmal road access from the Bere peninsula into Plymouth.

The Bere peninsula would still be served; Calstock and Gunnislake aren't on the Bere peninsula. A bus route going from Callington to Tavistock would actually have stops in Gunnislake unlike the station - which is about half a mile away and 100m higher.

 

[Brubulus]

In the current economic situation - likely to persist for many years - I suspect it is more likely that at least some Class 150s will be made to last a lot longer than people might consider desirable.

Diesels will never last as long as electrics and have significantly higher relative maintenance costs relative to electrics - especially as they age. The availability and cost of spare parts will also come into play - see the problems regarding Turbo availability. Given how soon many of the Northern leases are coming up for renewal, it will probably be more economically beneficial to replace the 150s than try and keep them for the long term. Scotrail's experience with the HST's shows why trying to keep very old trains in service tends to cost a lot more than just replacing them.

Triggered by reading the GWR thread and it seeming that two tinpot Cornish branchlines might be wagging the dog over what people think the GWR stock replacement spec would be.

1) Why have 20m units at all? I note that lots of EMUs, if not most, are 20m but I don't know why - more doors per set length or is it history, commuter land just being set up for multiples of that length?
2) Is a 2x20m DMU still practicable - ie will all the gubbins for a compliant engine etc fit (without catching fire etc..)?
3) Is it inevitable that Northern will need 2x20m DMUs - ie would going longer (eg new 195s replacing 150s) mean a massive infrastructure spend on platforms etc?

I guess I am asking as if Northern is inevitably going to order a stack of them its worth developing one for GWR, preferably a short version of their main buy (like SWR has 450 and 444 versions of the same thing). Otherwise the two problem branches should be adapted or binned!

1. Mostly because a lot of platforms are standardised to those lengths, so it is mostly due to history.
2. I'm not an expert but I'm pretty sure it would be.
3. Going over 20M creates all sorts of problems for a lot of lines regarding platforms and turning radii so it would be best avoided even if to simply provide a uniform fleet.
Something Northern really needs is a large fleet of 3 coach trains, given that there are a huge number of Northern services where 2 coaches causes unacceptable crowding, but doubling to form 4 coach trains is not viable.

The Bere peninsula would still be served; Calstock and Gunnislake aren't on the Bere peninsula. A bus route going from Callington to Tavistock would actually have stops in Gunnislake unlike the station - which is about half a mile away and 100m higher.

I do think it should be closed as a through operation, but some sort of heritage railway set up on that section. Any closure of that section needs to be accompanied by a commitment to provide at least an hourly bus to Gunnislake with integrated ticketing and connections to the railway along with the railways extension to Tavistock.

 

[Meerkat]

Any closure of that section needs to be accompanied by a commitment to provide at least an hourly bus to Gunnislake with integrated ticketing and connections to the railway along with the railways extension to Tavistock.

Not sure how that would be done legally, nor how equitable it would be - just because they had and lost a railway should they really get better transport provision that somewhere that might be better deserving but never had a railway?

 

[Trainbike46]

There must be a reason all recent DMUs have been longer. And longer is better for regional trains.

This is not true; 20m dmus have entered service over the last 5 years. Where it fits, a 23m coach has more capacity, so that contributed

But if length is an issue then Stadlers with power pods aren’t a very good answer

depends on whether the issue is total train length or length of individual cars. Where it is the first, ASDO is a solution in many cases. However, the big reason for 20m cars is the second, and then the powerpod doesn't matter.
Plus, there is nothing to say other manufacturers couldn't design different trains

It wouldn’t be the reason, more like the final straw……

Still the tail wagging the dog; Even though there are in fact unit designs around that could work this line, we should close it because the cars would be 20m not 23m

== Doublepost prevention - post automatically merged: 19 Feb 2023 ==

Not sure how that would be done legally, nor how equitable it would be - just because they had and lost a railway should they really get better transport provision that somewhere that might be better deserving but never had a railway?

Integrated public transport is a good idea in general - but I would be opposed to closing the GWR branches in the west, as most do pretty well. The political tide is also very much in the other direction, with relatively recent branch reopenings

 

[Bletchleyite]

The Marston Vale would be very easy to convert for 2x24m operation. It just involves moving a few signals and extending a few platforms (or using ASDO). It only isn't being done now because all those stations might be being demolished and rebuilt for the East West Rail 5 station proposal. The line is very quiet anyway. I don't think running buses is a huge motivation because the present bus service probably costs more than running it as a train, I'm sure I read it is using either 6 or 8 vehicles.

What's the other one that is an issue?

 

[61653 HTAFC]

The Marston Vale would be very easy to convert for 2x24m operation. It just involves moving a few signals and extending a few platforms (or using ASDO). It only isn't being done now because all those stations might be being demolished and rebuilt for the East West Rail 5 station proposal. The line is very quiet anyway. I don't think running buses is a huge motivation because the present bus service probably costs more than running it as a train, I'm sure I read it is using either 6 or 8 vehicles.

What's the other one that is an issue?

There's more than two.
Huddersfield to Sheffield is one (recent platform extensions were for 3x20m) but the bay at Huddersfield will be getting a bit more of an extension with the big rebuild as part of the Trans-Pennine upgrade. At present, 3-car trains have to pull closer to the buffers than is usually permitted in order to clear the TPWS grid. Indeed only the hybrid 150s can do so, the two prototypes are a bit too long so have to use Platform 4.

 

[Meerkat]

This is not true; 20m dmus have entered service over the last 5 years

What are they?

depends on whether the issue is total train length or length of individual cars. Where it is the first, ASDO is a solution in many cases. However, the big reason for 20m cars is the second, and then the powerpod doesn't matter.

ASDO is a bodge, and Doing it with a power pod in the mix would get a bit complicated.

Even though there are in fact unit designs around that could work this line, we should close it because the cars would be 20m not 23m

If every other line could use 23/24m then buying 20m units to keep two (probably one) line open would be silly.

I would be opposed to closing the GWR branches in the west, as most do pretty well.

Define pretty well - they are still economic basket cases aren’t they, particularly when it comes time to pay for new trains for them.

 

[JonathanH]

Define pretty well - they are still economic basket cases aren’t they, particularly when it comes time to pay for new trains for them.

Arguably it would work like buses, with hand-me-downs heading to the least lucrative routes. Trouble is that there isn't anything obvious to hand down. EMR taking on 170s from various places is a good illustration of how it could work though.

 

[Bletchleyite]

What are they?

There aren't any. However the 3-section FLIRTs are 65m which is close!

ASDO is a bodge

Better than closing lines.

and Doing it with a power pod in the mix would get a bit complicated.

No, it wouldn't, there is a corridor through the pod.

If every other line could use 23/24m then buying 20m units to keep two (probably one) line open would be silly.

Which lines exist where 2 x 24m won't fit at all? We've had the Marston Vale for one, but it's not insoluble and likely will be solved before the coming 150s are totally knackered. Sure, some might be 3 x 20m and have to go down to 2 x 24m.

== Doublepost prevention - post automatically merged: 19 Feb 2023 ==

There's more than two.
Huddersfield to Sheffield is one (recent platform extensions were for 3x20m) but the bay at Huddersfield will be getting a bit more of an extension with the big rebuild as part of the Trans-Pennine upgrade. At present, 3-car trains have to pull closer to the buffers than is usually permitted in order to clear the TPWS grid. Indeed only the hybrid 150s can do so, the two prototypes are a bit too long so have to use Platform 4.

3 x 20m would fit 2 x 24m, though. Not ideal, but not line closure territory.

Are there any lines bar the Marston Vale where only Classes 150 and 153 fit?

 

[JonathanH]

Are there any lines bar the Marston Vale where only Classes 150 and 153 fit?

Looe, Gunnislake

 

[Ken H]

what about Cumbrian coast. I think its 23m 156's only. Whats the strategy there?

 

[Bletchleyite]

Looe, Gunnislake

I'm sure I've looked at Looe before, but looking at it again on Streetview and aerial view, it appears there are two options to lengthen it - one would be to purchase and demolish the fairly ugly building at the platform end and extend that way, the other would be to build a new platform on the other side. Or just use ASDO. It may be a bodge but it works. The Liskeard platform is plenty long enough and the other stations are very quiet so ASDO would be fine.

Gunnislake is more than 40m long, I've found a picture of 2.150 in the platform with enough room for another full coach, let alone another 8m.

== Doublepost prevention - post automatically merged: 19 Feb 2023 ==

what about Cumbrian coast. I think its 23m 156's only. Whats the strategy there?

Probably clearing 195s. There are apparently only a couple of narrow spots which could be singled. 153s also fit, by the way, 150s are too wide.

 

[MarkyT]

The Bere peninsula would still be served; Calstock and Gunnislake aren't on the Bere peninsula. A bus route going from Callington to Tavistock would actually have stops in Gunnislake unlike the station - which is about half a mile away and 100m higher.

That Gunnislake station isn't at the nominal 'heart' of Gunnislake village isn't really a problem. The station is at the boundary with the adjacent village of Drakewalls a bit higher up the hill, near a lot of housing that continues further uphill along the A390 to St Ann's Chapel. There are local daytime buses between Tavistock and Callington serving the various Gunnislake area villages with a few journeys going further afield. The villages join up to form a largely continuous settlement for around 2 miles along the A390 corridor.

 

[JonathanH]

Gunnislake is more than 40m long, I've found a picture of 2.150 in the platform with enough room for another full coach, let alone another 8m.

Platform at Gunnislake is fine for longer trains - the issue is the curve at Calstock which can't cope with two 23m vehicles coupled together.