DMU ages at key dates

[Haydn1971]

With all the discussions over when DMU's should be replaced, refurbished, trashed etc, I sat down the other night and established the following;

In 2013 we have the following commuter DMU "carriage" numbers
- Less than 25 yrs old = 1786
- 25-35 yrs old = 686
- over 35 yrs old = 0

In 2019 this becomes
- Less than 25 yrs old = 915
- 25-35 yrs old = 1551
- 36-40 yrs old = 6 (150/0's)
- over 40 yrs old = 0

In 2024 this becomes
- Less than 25 yrs old = 715
- 25-35 yrs old = 781
- 36-40 yrs old = 977 (the whole 14x/15x fleet less a few 158's and all the 159's)
- over 40 yrs old = 0

In 2032 this becomes
- Less than 25 yrs old = 99
- 25-35 yrs old = 816
- 36-40 yrs old = 457 (remaining 158/159/165/166 fleets)
- over 40 yrs old = 1101 (14x/15x/16x fleet)

In 2042 this becomes
- Less than 25 yrs old = 0
- 25-35 yrs old = 83 (172 fleet only)
- 36-40 yrs old = 460 (some 168/170 & all 171/185)
- over 40 yrs old = 1913

The 496, 180/22x fleet "carriages" are 25-35 yrs old in 2032, with 313 "carriages" over 40 years old by 2042

Thoughts ?

 

[michael769]

Diesel units have a design lifespan of 30years.

 

[tbtc]

Thoughts ?

1. You have a lot of time on your hands

2. There will be a lot of electrification over the next decade - I don't think anyone believes that there will be 1,913 DMUs running in 2042 that are over 40 yrs old - "commuter" DMU numbers should be vastly reduced after CP6

 

[Haydn1971]

LOL - cheers, it didn't take long to be honest - numbers from Wikipedia, so won't be 100% accurate either

Specifically, Michael, yes, I agree, which I why I picked a vague 25-35 year term, in that procurement for replacements "ideally" would be considered at about 25 years of age, rolling new stock out as the old gets to 30 years, but feel that the reality is more 30 & 35 years respectively.

TBTC - the numbers are representative of stock that would be theoretically available - I'd really hope that 40 year old DMU stock wasn't still running but half expect some 36-40 year old stock to be rattling around somewhere.

For me, the 2019-2024 period is where things are getting very interesting numbers wise and very reliant on what electrification is achieved. Anyone care to offer a thought on numbers and ages of cascaded EMU's by 2024 ?

 

[WatcherZero]

Diesel units have a design lifespan of 30years.

yes, design life of 30 years subject to at least one major mid life refurbishment.

 

[61653 HTAFC]

Of course as time moves on, unless there's a breakthrough in diesel engine design in the next 10 years or so then we may have no choice but to 'make-do and mend' our existing DMU fleet for those routes that remain unelectrified simply because the existing trains have grandfather rights exempting them from emissions regulations. Especially as there doesn't appear, in the minds of the manufacturers, to be a business case for doing the R&D into an engine that meets current standards and will fit in our loading gauge!

 

[IanBanks-Jones]

It all seems a bit silly to me. A DMU built today may still be going in 40 years, but there is no way of knowing when it will be replaced. Were the 1960's vintage units built by people who were overly concerned by what was to replace them, or the date of their demise? Who knows what stock orders and/or electrification plans will actually be followed through? It is all just supposition. Although I expect some (as always) will make overly simple statements. (like that in 30 years, all the trains from today that are still running will be 30 years older!)

 

[WatcherZero]

Well the Pacers when built were supposed to be a stopgap and only expected to be operating upto 20 years not 30+

 

[Class172]

With the number of new DMUs required decreasing over the next CPs, I think we should take the view that in stead of planning ahead that every unit should last no more than 30 years, we should treat each class differently as some may be knackered by 25/30 years old and only useful for the scrapheap (class 142?), whilst other classes, could be kept going for much longer without too much trouble (I can imagine a class 158/159 still going at over 35 years) - after all we still have a couple of 121s working on the network, and they're 50 years old!

 

[LE Greys]

With the number of new DMUs required decreasing over the next CPs, I think we should take the view that in stead of planning ahead that every unit should last no more than 30 years, we should treat each class differently as some may be knackered by 25/30 years old and only useful for the scrapheap (class 142?), whilst other classes, could be kept going for much longer without too much trouble (I can imagine a class 158/159 still going at over 35 years) - after all we still have a couple of 121s working on the network, and they're 50 years old!

Most definitely. A lot depends on stock available and the routes on which it runs. We already have 158s on long Scottish routes for which they are not suited, their big advantage of being able to do 90 mph is nullified by the speed limit. If anything lasts to 50+ years, it'll be the 156, simply because there is nothing any better to replace them on local lines. You can't really farm out a 185 to the Far North or East Anglia, but you can with a 156.

 

[Blindtraveler]

Diesel units have a design lifespan of 30years.

And I don't see the 22xs sticking around for that long, or at least certainly not the poorly maintained examples at XC. The thought of some of the post privation DMUs reaching the same ages as the 15xs will be at withdrawal isn't a nice one in many cases but it does depend on the operators mid-life refurbs. Realistically we are sitting on a time bomb as the likes of Clubmans and first build of 170s at LM, Scotrail and GA will be due major mid life work in the next few years making withdrawals of 14x units via cascades quite interesting.

--- old post above --- --- new post below ---

Most definitely. A lot depends on stock available and the routes on which it runs. We already have 158s on long Scottish routes for which they are not suited, their big advantage of being able to do 90 mph is nullified by the speed limit. If anything lasts to 50+ years, it'll be the 156, simply because there is nothing any better to replace them on local lines. You can't really farm out a 185 to the Far North or East Anglia, but you can with a 156.

having talked to a few far north guards they think the 158s cope better with the run and there are a few stretches where they can do over 75.
I do agree though, a major overhaul of the supersprinter fleat could make them0reach the half century although I would put them all in one place, with whatever constitutes Northern by then! Cumbria coast, leeds Morcom, Blackpool Manchester, commuter runs and 142x replacement.
It seams inevitable that when Edin Glasgow is wired that some 170s will cascade and if they dont move to duties such as making all Aberdeen and/or HML Trains 6 car then hopefully the WHL/GSW will get them. Failing that GA makes sense as they have units of same age and could rid themself of sprinters, potentially even swapping0some of the 2 car sets away from XC in the process

 

[LE Greys]

having talked to a few far north guards they think the 158s cope better with the run and there are a few stretches where they can do over 75.
I do agree though, a major overhaul of the supersprinter fleat could make them0reach the half century although I would put them all in one place, with whatever constitutes Northern by then! Cumbria coast, leeds Morcom, Blackpool Manchester, commuter runs and 142x replacement.
It seams inevitable that when Edin Glasgow is wired that some 170s will cascade and if they dont move to duties such as making all Aberdeen and/or HML Trains 6 car then hopefully the WHL/GSW will get them. Failing that GA makes sense as they have units of same age and could rid themself of sprinters, potentially even swapping0some of the 2 car sets away from XC in the process

That's interesting. From what I remember, they aren't that well-liked, although there is probably a broad spectrum of views (I know at least one driver who loves them). From my point of view, they are the best 158s, the ones with the best seats and where the air-con tends to work. I really hope that the SPT 170s, plus a few Haymarket units, end up strengthening the Aberdeen-Inverness runs, perhaps by transferring ten or so to Inverness depot. I also hope that wires reach up to Dyce one day, although maybe not Inverness because of problems with snow and the relative lack of traffic. Converting Haymarket to an all-electric depot and out-basing the remaining 170s in Dundee might be an option.

 

[HSTEd]

Of course as time moves on, unless there's a breakthrough in diesel engine design in the next 10 years or so then we may have no choice but to 'make-do and mend' our existing DMU fleet for those routes that remain unelectrified simply because the existing trains have grandfather rights exempting them from emissions regulations. Especially as there doesn't appear, in the minds of the manufacturers, to be a business case for doing the R&D into an engine that meets current standards and will fit in our loading gauge!

Cummins now has a QSK-19 derivative that fits in our loading gauge and meets the latest EU emissions regs (Stage IIIB?). This is the new compact QSK-19R which does not appear significantly larger than the original, at least in the crucial height dimension.

And the IEP will obviously need underfloor diesels that meet these restrictions.

 

[ainsworth74]

or at least certainly not the poorly maintained examples at XC.

You mean those units that are regularly amongst the most reliable in the country?

 

[Haydn1971]

Whilst there appears to be a clear view amongst many that there isn't a market for developing a diesel multiple unit - it's clear that Siemens have a product family that could provide a DMU, similarly with Hitatchi, their "A Train" product is clearly being utilised with a diesel engine in the IEP, is it really that big a step to merge the commuter based and IEP based product lines into a DMU for the UK market ? I don't really buy into the argument that there aren't diesel options that fit with emissions standards either, especially with all the diesel HGV's, generators and marine applications out there.

 

[hwl]

Whilst there appears to be a clear view amongst many that there isn't a market for developing a diesel multiple unit - it's clear that Siemens have a product family that could provide a DMU, similarly with Hitatchi, their "A Train" product is clearly being utilised with a diesel engine in the IEP, is it really that big a step to merge the commuter based and IEP based product lines into a DMU for the UK market ? I don't really buy into the argument that there aren't diesel options that fit with emissions standards either, especially with all the diesel HGV's, generators and marine applications out there.

2 main non technical issues:

1. Small order size and the large R&D cost spread across a small initial batch of units (see quoted cost for TfL centre carriages for the Goblin 172s). A large batch ordered in 2018/19 (i.e. post publication of CP6 electrification etc plans) should be able to spread the development costs across a large number of units.

2. Ordering new DMUs now would mean the ROSCOs might not be able to squeeze every last penny out of their existing DMUs and they aren't certain how long they would be able to lease their newly ordered units, i.e. they might not be able to get at least 25 years (preferably 30+) out of them with out a long term electrification plan in place (NR work in progress).

1 Main technical issue:
As far as I can see the problem is not the engine but the exhaust system. (MTU also have a IIIb version of the cl172 engine.) The issue (not just in trains but also in other vehicles especially in small diesel cars and HGV tractor units at the moment) is finding the space near the end of the exhaust system^ for the particle traps, which in a DMU would probably entail redesigning the carriage body* to create more external space. This would then probably entail going through all the crash worthiness stuff again. Setting up the engines and exhaust systems so they work reliably at all revs and trains speeds is also much harder and more time consuming. --> Big cost which needs to be spread over a big an order as possible.

As you have noticed, the engine not fitting bit is a load of bull, the exhaust system not fitting is the real issue as it is in parts of the auto industry at the moment too.


[^ for high efficiency]
[* in the case of 172 the carriage end, for a 185 type follow on design the roof]

 

[Kali]

Perhaps it might be time to look at alternate self-propulsion fuel, also. Hydrogen would solve all sorts of issues, but create the obvious one of carting a tank of hydrogen around - while I'm happy to believe that would be sufficiently safe, I'm not sure everyone else would agree. I'm not aware of what's going on in the field of creating cleaner hydrocarbon fuels but surely this has to be a big field of research, currently.

Are there any usable variable vane hydraulic transmissions around? that would let the engines run at the most efficient/least polluting RPM ( or anything inbetween ).

 

[Blindtraveler]

That's interesting. From what I remember, they aren't that well-liked, although there is probably a broad spectrum of views (I know at least one driver who loves them). From my point of view, they are the best 158s, the ones with the best seats and where the air-con tends to work. I really hope that the SPT 170s, plus a few Haymarket units, end up strengthening the Aberdeen-Inverness runs, perhaps by transferring ten or so to Inverness depot. I also hope that wires reach up to Dyce one day, although maybe not Inverness because of problems with snow and the relative lack of traffic. Converting Haymarket to an all-electric depot and out-basing the remaining 170s in Dundee might be an option.

pre refurb they were unpopular I agree but until my Mrs moved off Orkney I used the run regularly and havnt met anyone yet who would rather see a 156 working far north again. They are indeed the best around and work well, even the Haymarket units can go some despite interiors being overdue some work. I think just for once TS are unsure of the future oo the DMU front as they have not only failed to refurbish these units but also to put the first 24 or so 170s through the current refresh work suggesting its all to play for!

--- old post above --- --- new post below ---
wires north of Dunblane is I think a dream for a long time yet and given recent climb downs and cutbacks on this very subject the requirement for DMUs in Scotland will remain high for a while. I would have said that the way to do it would be to put 170s on GSW, WHL and commuter runs with0the various clearing work being done and perhaps X Transpenine 185s or voyagers, meridians or 180s on the express duties. Potentiall also for some swapping of 2 and 3 car turbostar sets for maybe the highland work in future?
--- old post above --- --- new post below ---

Whilst there appears to be a clear view amongst many that there isn't a market for developing a diesel multiple unit - it's clear that Siemens have a product family that could provide a DMU, similarly with Hitatchi, their "A Train" product is clearly being utilised with a diesel engine in the IEP, is it really that big a step to merge the commuter based and IEP based product lines into a DMU for the UK market ? I don't really buy into the argument that there aren't diesel options that fit with emissions standards either, especially with all the diesel HGV's, generators and marine applications out there.

I think you make a good point here however I would say that whether IEP based DMU get anywhere or even the technology from them gets anywhere depends largely on how IEP goes in Bi Mode form. If as many feer its the Next Generation Voyager then it will bf so controvercial that the apetite for qeusing any bit of it will be supressed greatly. Given who is building it though It should be a success and if so, problem solved!

 

[DXMachina]

Would there be a difference in lifespan between DMU units principally used for long-distance routes (158,159) and those on short-hop commuter services due to different engine & transmission wear profiles? (I assume brake systems are seen as disposable)

Such is seen with road vehicles because running at consistent speeds is less damaging than constant varying of power.

 

[Kali]

Trains spend most of their time coasting, irrespective of service profile - it's one reason why rail is efficient. I would suspect hours in service is what counts most.

 

[WatcherZero]

Its been said that the Northern units have worn a bit more than the same classes in use elsewhere due to the shorter distance between stops meaning more acceleration and braking (primary cause of wear) rather than cruising at constant speed (which produces little wear).

 

[Bevan Price]

--- old post above --- --- new post below ---
wires north of Dunblane is I think a dream for a long time yet and given recent climb downs and cutbacks on this very subject the requirement for DMUs in Scotland will remain high for a while. I would have said that the way to do it would be to put 170s on GSW, WHL and commuter runs with0the various clearing work being done and perhaps X Transpenine 185s or voyagers, meridians or 180s on the express duties. Potentiall also for some swapping of 2 and 3 car turbostar sets for maybe the highland work in future?

[/i]

I think that once the question of Scottish dmu replacements comes up for discussion officially, (say around 2025 - 2030) it will be decided to electrify Dunblane to Perth, Dundee & Aberdeen, plus Edinburgh to Dundee and the Fife Circle. The GSWR route from Carlisle to Glasgow is also a long term possibility. Eventually, the only non-electrified routes in Scotland might be the West Highland line, Girvan to Stranraer, and anything north of Perth / Inverness (or Dyce).

 

[RobShipway]

It is a shame that you cannot use Kinetic Energy for powering these units in the same way that the PPM is powered that does the Stourbridge town - Stourbridge Junction route

 

[jopsuk]

The PPM's stored kinetic energy flywheel system is only suitable (if at all) for light loads over short distances. The Highland Mainline (HML) is a serious route- may have commented that Turbostars do struggle a bit on it (they're not as good at hills as 158s) and the Highland Chieftain is the once service where the 2+9 HST formation reaches the limits of its viability- the 2+7 Western sets would be a bit more sprightly up there, but south of Edinburgh would be far too low capacity.

The West Highland, again, has serious climbing with long distances between stations and is having some services increased in length (capacity) due to how busy they are! Not a place for a tiny little bus with a flywheel.

 

[Oswyntail]

...Not a place for a tiny little bus with a flywheel.

But it would be fun to watch them trying! And the passengers getting off to push.

 

[Blindtraveler]

the HML on a turbo is a noisy experience as the 170s are just not good. The 1 northbound of the day booked 158, the 10:36 from EDB, the HC and the sleaper are my fave INV trains. The HSTS Dont do as badly with the MTU Power units.

 

[RobShipway]

Would a nine coach class 222 make it any easier than a HST on the Highland Chieftain?

 

[sprinterguy]

Would a nine coach class 222 make it any easier than a HST on the Highland Chieftain?

Most probably - Given that every vehicle of a 222 is powered, that gives a considerably better power to weight ratio for the 222, given that the 222 has 6750hp available against the 4500hp of an HST, and far greater adhesion as power is being transferred through many, many more axles on a DEMU such as the 222.

Of course, given that the "Highland Cheiftain" is one of the services directly involved in the East Coast's future IEP programme, how a 222 would perform on the Highland Mainline is probably a moot point.

 

[The Ham]

Most probably - Given that every vehicle of a 222 is powered, that gives a considerably better power to weight ratio for the 222, given that the 222 has 6750hp available against the 4500hp of an HST, and far greater adhesion as power is being transferred through many, many more axles on a DEMU such as the 222.

Of course, given that the "Highland Cheiftain" is one of the services directly involved in the East Coast's future IEP programme, how a 222 would perform on the Highland Mainline is probably a moot point.

However how a 222 (which has engines all the way along) compares with a HST (with just engines at each end) would be the same as any MU and any Loco hauled train. Therefore it is likely that the IEP will perform well on such a hilly route.