Creation of class 230 DEMUs from ex-LU D78s by Vivarail

[edwin_m]

I’d argue the supplier that supplied the power packs should have check the fuel hoses were tight enough - in my opinion, it’s more down to quality control not being good enough and also a wee bit of haste to get the unit ready.

There were a several factors that suggested to me that the supplier wasn't used to designing for the railway environment. Components mounted on trains encounter more severe vibrations than those fitted to road vehicles. Arguably a train needs to be more "fire-tolerant" as it may have to continue to a safe place (ie not a viaduct or tunnel) before people can evacuate. VivaRail obviously selected the supplier and ought to have provided the rail expertise themselves if the supplier couldn't.

 

[route:oxford]

Components mounted on trains encounter more severe vibrations than those fitted to road vehicles.

This comes up from time to time. Why do components mounted on trains suffer from more severe vibrations than those on road vehicles?

 

[The Ham]

This comes up from time to time. Why do components mounted on trains suffer from more severe vibrations than those on road vehicles?

Possibly because trains are in service for longer than lorries.

 

[Xenophon PCDGS]

There were a several factors that suggested to me that the supplier wasn't used to designing for the railway environment. VivaRail obviously selected the supplier and ought to have provided the rail expertise themselves if the supplier couldn't.

One might ask if there are not suppliers with the required rail expertise that Vivarail could have approached.

 

[northwichcat]

I’d argue the supplier that supplied the power packs should have check the fuel hoses were tight enough - in my opinion, it’s more down to quality control not being good enough and also a wee bit of haste to get the unit ready.

Ultimately it was Vivarail's responsibility to order suitable parts for a converted train.

Given Abellio now plan to use D-Trains on Marston Vale what still needs to be done to get D-Trains cleared to run on the National Rail network?

 

[Taunton]

This comes up from time to time. Why do components mounted on trains suffer from more severe vibrations than those on road vehicles?

Pneumatic tyres on road vehicles provide, in themselves, considerable suppression of shocks. Rail vehicles don't have this. It would be interesting to know what the component life differences are on the Paris Metro between comparable steel wheel and pneumatic tyre trains.

Anyone who has ridden in two 1920s vehicles, one with pneumatic tyres and one with solid tyres, will appreciate the difference.

 

[coppercapped]

Pneumatic tyres on road vehicles provide, in themselves, considerable suppression of shocks. Rail vehicles don't have this. It would be interesting to know what the component life differences are on the Paris Metro between comparable steel wheel and pneumatic tyre trains.

Anyone who has ridden in two 1920s vehicles, one with pneumatic tyres and one with solid tyres, will appreciate the difference.

There are significant differences, as I am sure you are aware given your background, between road and rail vehicle suspensions. Rail vehicles have both primary suspension - between the wheelset and the bogie frame - and secondary suspension - between the bogie frame and the vehicle body. The pneumatic tyres of road vehicles are in some respects similar to rail's primary suspension but this 'suspension's' travel is very limited and the main vibration filter is represented by the vehicle's spring and damper arrangements. Vehicle suspensions have moved on since the cart springs of the 1920s.

Rail suspensions allow very low levels of vibrations to pass to the vehicle body - sitting in a coach at 125mph is quite smooth compared to my local bus at 25mile/h on one of my town's potholed road surfaces! The parts of a rail vehicle which are exposed to high levels of shock ('g' levels of around 100 have been measured) and vibration are those before the primary springs - that is the wheelsets, bearings, axlebox locating members, any wheelset mounted equipment - drive gears, housings and the like - and the wheel end half of the primary spring. Bogies are exposed to the vibration and shock levels which are passed through the primary suspension.

The point of all this is to point out that stuff - equipment and passengers - carried by the coach body in fact live in a quite benign environment.

 

[highspeed990]

Will the traction motors have the same sounds as they did on the district line?
Or will it have changed?

 

[Domh245]

Will the traction motors have the same sounds as they did on the district line?
Or will it have changed?

The prototype certainly had the same motors, and sounded very familiar in some videos. However, last I read, Vivarail were planning on changing the motors on later conversions to allow for regenerative braking with their battery packs, so it is unlikely that they'll be the same.

 

[D365]

Yep the battery units will be receiving AC traction motor packs.

 

[highspeed990]

The prototype certainly had the same motors, and sounded very familiar in some videos. However, last I read, Vivarail were planning on changing the motors on later conversions to allow for regenerative braking with their battery packs, so it is unlikely that they'll be the same.

And here's me getting my hopes up! I love that sound!

Yep the battery units will be receiving AC traction motor packs.

I thought D stock motora were DC?

 

[highspeed990]

I just watched a video and yes, I can still hear the distinct D stock traction motor! They have many years left in them, have no idea why they removed them from the tube so early.

 

[D365]

I thought D stock motora were DC?

They were. The Class 230 battery conversions will be retractioned.

I just watched a video and yes, I can still hear the distinct D stock traction motor! They have many years left in them, have no idea why they removed them from the tube so early.

A unified subsurface fleet has advantages.

 

[Bletchleyite]

Anyone any idea what LM are having? DMU or battery? I guess DMU?

 

[coppercapped]

I just watched a video and yes, I can still hear the distinct D stock traction motor! They have many years left in them, have no idea why they removed them from the tube so early.

The reason has been well reported in both the enthusiast's and the railway technical press over the past few years.

In order to maximise the number of trains which can be operated on the sub-surface lines it is important that all the trains have the same performance characteristics. The S7 and S8s are more sprightly than the D78s, they have regenerative braking and are designed for the next generation of on-board signalling/train control. It would not have been cost effective to make such significant modifications to the D78s, especially as maintaining the service with several units being out of service for the rebuild would have been impossible.

There are usually good reasons for such decisions.

 

[coppercapped]

Anyone any idea what LM are having? DMU or battery? I guess DMU?

It has been reported that the battery pack replaces one of the diesel packs on a power car. However whether this means that a two car unit will have two diesel engines and two battery packs or three diesel engines and one battery pack has not been made clear - at least in my understanding.

 

[Mikey C]

The reason has been well reported in both the enthusiast's and the railway technical press over the past few years.

In order to maximise the number of trains which can be operated on the sub-surface lines it is important that all the trains have the same performance characteristics. The S7 and S8s are more sprightly than the D78s, they have regenerative braking and are designed for the next generation of on-board signalling/train control. It would not have been cost effective to make such significant modifications to the D78s, especially as maintaining the service with several units being out of service for the rebuild would have been impossible.

There are usually good reasons for such decisions.

The S7s feel massively more spacious inside than the D78s too, so much easier to walk through the carriages.

Off topic, but the D78s feel narrower inside than the S7s, is that a by product of having longer carriages?

 

[Dstock7080]

Off topic, but the D78s feel narrower inside than the S7s, is that a by product of having longer carriages?

The widest point of a D Stock was at solebar level then gently tapered up to cantrail. The cars were longer too.
S Stock have the bulge to allow the seats to be pushed back, thus freeing up the floorspace.

 

[Domh245]

The latest development in the story of the D-Train: 25kV

RAIL article

Vivarail has been developing proposals to include its modular D-Trains within the next Wales & Borders franchise, which commences in October 2018.

A document has been circulated to all four shortlisted bidders detailing the suitability of the trains - built from refurbished ex-London Underground vehicles - from a performance, emissions and value for money perspective.

Vivarail proposes to offer three-car electric multiple units for use on the Valley Lines. They would run to the outskirts of Cardiff using power obtained from a 25kV overhead supply, before running for approximately 40 minutes using on-board batteries to destinations including Rhymney and Merthyr Tydfil.

This would require short extensions of overhead line equipment to be made from Cardiff Central to the city’s northern suburbs, in order to provide sufficient charge to the lithium ion batteries. However, the proposal would negate the need to electrify the entire Valley Lines.

Vivarail says the first D-Train could be delivered nine months after receipt of an order, and could be fitted with diesel generator sets as an interim measure before being reconfigured at a later date when OLE is installed.

If OLE is never erected, the Long Marston-based company adds that batteries could also be charged from track level charging stations if required.

The three-car D-Trains can reportedly accommodate 404 passengers, are fitted with Wifi and USB sockets, and can be fitted with air-conditioning and a universal access toilet.

The diesel-powered variant of the D-train is already fully certified, while Vivarail anticipates certification for the battery-powered variant in early 2019.

Vivarail Chairman Adrian Shooter told RAIL: “Having spent almost two years talking to a great many stakeholders in Wales, so that we could understand what they really want, we believe that we have a set of proposals which will enable franchise bidders to cost-effectively make major improvements to the quality of many train services in Wales.”

 

[47802]

Well they could look at the document and then file it in the bin. I suspect fitting a pantograph to the roof of a D train could be interesting and how much is this concoction going to up the price. On the other hand you could just get some 769's, or proper new trains.

But then I imagine the W&B franchise is the last hope of flogging these things in significant numbers so they are going all out.

 

[samuelmorris]

As you would expect. This is pretty much the last chance to sell any decent volume of the product. Ideally if electrification was on the cards it would seem better to make use of some of the large quantity of off-lease EMUs, but I don't have high hopes for extension of electrification in Wales given they can't even stick to plans for the mainline, let alone the branches.

 

[gareth950]

As you would expect. This is pretty much the last chance to sell any decent volume of the product. Ideally if electrification was on the cards it would seem better to make use of some of the large quantity of off-lease EMUs, but I don't have high hopes for extension of electrification in Wales given they can't even stick to plans for the mainline, let alone the branches.

Which is why Welsh Govt want to strip NR of the responsibility of wiring the 'Core Valley lines' north of Cardiff and hand it over to the Operator of the new franchise to take on.

 

[samuelmorris]

I can't say I blame them. After Railtrack the concept of privatised infrastructure worries me but given the recent quality of NR work I fail to see how it could be much worse at the moment...

 

[Mikey C]

Well they could look at the document and then file it in the bin. I suspect fitting a pantograph to the roof of a D train could be interesting and how much is this concoction going to up the price. On the other hand you could just get some 769's, or proper new trains.

But then I imagine the W&B franchise is the last hope of flogging these things in significant numbers so they are going all out.

Yes, adding a pantograph sounds like a massive exercise for units which will be nearly 40 years old by the time they get back into service

As I've said before, there's an awful lot of project drift here...

 

[Rational Plan]

Why not forget about this obsession with overhead wire and just 3rd rail the suburban lines between the stations, with batteries to cover stations and level crossings. 3rd rail is much cheaper to install (no bridge changes). It is not as if the valleys are going to have trains going over 100mph. They could still use these trains with the third rail, or dual voltage in the future.

 

[Roast Veg]

Why not forget about this obsession with overhead wire and just 3rd rail the suburban lines between the stations, with batteries to cover stations and level crossings. 3rd rail is much cheaper to install (no bridge changes). It is not as if the valleys are going to have trains going over 100mph. They could still use these trains with the third rail, or dual voltage in the future.

There will be no new third rail installations, especially outside of existing networks. The ORR does not see it as safe enough for new builds, and the ultra-long-term aspiration is to replace it all (though it may take a century or more). The losses from bridge replacement are recouped from fewer substations, lower maintenance costs and cheaper rolling stock.

 

[samuelmorris]

Off-topic but are AC overhead EMUs actually cheaper than DC ones? Seems odd given the extra complexities of a transformer and pantograph versus just having pickup shoes, which unless retractable may not even count as moving parts.

Nonetheless I agree, I think third rail has run its course and do somewhat agree with the aspiration to replace it, though of course given recent progress, whether it'll ever be achieved is up for debate. Solutions like the 230 are actually quite helpful ways to get round the problem, they would be more helpful still if applied to higher-specification units that have fewer drawbacks.

 

[Rational Plan]

There will be no new third rail installations, especially outside of existing networks. The ORR does not see it as safe enough for new builds, and the ultra-long-term aspiration is to replace it all (though it may take a century or more). The losses from bridge replacement are recouped from fewer substations, lower maintenance costs and cheaper rolling stock.

The ORR is a beaurcracy not God, it can be over ruled. It has made overhead instalation too expensive and no one will be replacing 3rd rail with over head, when it's due for renewal. Those calculations it made only worked on the original sums, not on three times the cost outcomes. A few replaced personnel and rules can change. Besides is the third rail line a law, or just a guidline, considering the steaminf pile that is electrificationn the ORR must be thinking of a face saving outcome.

 

[Gareth Marston]

Despite anything Vivarail say the D train concept has been firmly given the thumbs down by Stakeholders in Wales already, there politically unacceptable with everyone else getting new trains - the best thing Vivarail can do is to go round and dump them on Philip Rutnam's (ex Permanent Secretary at DfT) lawn and see if hes still so keen on them.

 

[XCTurbostar]

Despite anything Vivarail say the D train concept has been firmly given the thumbs down by Stakeholders in Wales already

What gives you that impression? I know at least two of the bidders are interested in 230s..