Hitachi trains grounded

[ess1uk]

What’s availability like now? 

[Afroal05]

In terms of cracks, nothing has really changed. Availability is hanging around 70 units a day and this has taken a dip in the last couple of months although cracks are not the reason. Covid/sickness within engineering teams has been the biggest problem and it is noticeably hitting the fleet with a decent number of GUs out and other defects piling up, a common defect at the moment seems to be holes developing in wheelsets. This is compounded a little bit by GWR driver sickness/covid which does mean that not all of the exam requirements are delivered in the required timeframes and this throws the Hitachi exam plan out a bit. When things are so delicately planned on what few maintenance man hours there are this does mean that if you miss the desired window (or day) to deliver the unit then its exam might have to be kicked back several days or cause a bunching of exams/defect repair and extra pressure on depots.

I won't comment on opinions about the way the whole maintenance and rolling stock management situation works compared to when HSTs (and other units still withing the franchise) are maintained in house but that could easily fill another topic in itself and it is certainly more complicated this way (at face value anyway).

 

Further crack analysis and testing is being conducted at the moment with a unit covering the network with measuring equipment which I believe is to try and understand the things and forces that might have caused the issue in the first place. This diagram has been around before with the unit trying to go everywhere IETs go and get measurements but it has always fallen victim to driver shortages a little bit. 802007 went to Penzance today and the diagram is booked to go to Swansea tomorrow.

 

In terms of fleet interoperability and other titbits then things have largely been positive. On Friday 10th December an Ops document was sent round confirming that Class 800 and 802 traction could be coupled together in passenger service. Previously this had only been permitted for rescue and recovery purposes and wasn't allowed even on empty trips to depot. On Saturday 11th a situation presented itself where I was able to attach an 800/802 and we ran the first legal pair in traffic. Unfortunately I have to throw that caveat in as we had done it by accident before and only realised after the event. 

This is a huge development for controllers and makes it much easier to keep trains moving. The only restrictions when 800/802 are coupled together are that rheostatic braking isn't available and when the 800 is leading the formation the bodyside cameras are not available for the 802 unit.

 

The first occurrence of a 9 car and a 5 car took place just after Christmas as well. This is still only permissible for recovery purposes. A 9 car 802 arrived at Cheltenham Spa which had been struggling with GUs shutting down and they all packed in on arrival at Cheltenham. The driver was able to restart one and limp into Alstone sidings but when there it shut down again and after a quick investigation it was concluded the unit was out of fuel! (Root cause was a failure of the fuel pumps at North Pole the day before and it wasn't communicated that the 802 hadn't been fuelled). The recovery was made by sending a fitter to Cheltenham who was able to trip out the fuel sensor in one of the tanks so that it wasn't reading (or correctly reading) the fuel quantity. IETs are set so that the GU shuts down when the fuel tank reaches 5% to prevent it running out completely and seizing up. The unit then crawled to Gloucester where it was attached to a healthy 800/5 (meaning it was an 802/9 & 800/5 combination) and dragged back to Reading where it split and both units were able to move to North Pole on electric. The 14 car drag did require two drivers as the TMS in the leading unit cannot observe more than 12 vehicles so a driver, or competent person, has to be in the rear unit to make sure that if it bursts into flames someone can react accordingly.

 

Finally when a unit is prepped for service the prep certificate used to be valid for 35.5 hours after which the unit was required to visit a depot for another prep. This time window has now been extended to 48hrs which offers a much greater versatility when swaps are required during the day to deliver other exam requirements or during disruption.

 

Unfortunately this is probably the last update of this detail that I will be able to give as I will be leaving my role that allows me this level of information and operational involvement and I will instead begin training to be a driver in a couple of weeks time. I will try and provide useful or informative updates if I can in the future.

 

Al

[phil-b259]

8 minutes ago, Afroal05 said:

 

Unfortunately this is probably the last update of this detail that I will be able to give as I will be leaving my role that allows me this level of information and operational involvement and I will instead begin training to be a driver in a couple of weeks time. I will try and provide useful or informative updates if I can in the future.

 

Al

 

Good luck with the next stage in your railway career and thank you for what you have contributed to this thread.

[Gordon Connell]

ORR report now issued: Rail regulator publishes Class 800 series safety report |

[Dunsignalling]

Interesting that the rectification program is now scheduled to take as long as six years "to minimise the number of units out of service at one time".

 

I suspect workshop/manpower availability may also be a factor. However, the extended timescale will also provide the opportunity to assess the efficacy and durability of the fixes before all sets have been treated.

 

John

 

 

[melmerby]

45 minutes ago, Gordon Connell said:

ORR report now issued: Rail regulator publishes Class 800 series safety report |

The BBC has been reporting this all morning with two different causes depending whether you read the tv text or listen to the radio news.

Text is saying they were caused by salt corrosion, radio is saying stress fatigue.

Edited April 7, 2022 by melmerby

[St Enodoc]

32 minutes ago, melmerby said:

The BBC has been reporting this all morning with two different causes depending whether you read the tv text or listen to the radio news.

Text is saying they were caused by salt corrosion, radio is saying stress fatigue.

Stress corrosion cracking, as stated in the ORR press release. A characteristic form of failure with aluminium.

Edited April 7, 2022 by St Enodoc
characteristic is probably a better word than typical

[corneliuslundie]

The web report says both in different places:

"The ORR investigation found the design of the trains complied with existing standards but that corrosion cracks were found on lifting points - which allow carriages to be raised during maintenance work - resulting from the use of a particular type of aluminium, which was corroded by salt in the air.

It said fatigue cracking was caused by the "trains experiencing greater loads from train movement than allowed for in the original design"."

So the aluminium was not suitable for use on trains on coastal routes and the standard was not adequate, since the report says that standards were met.

Also from the BBC website:

"It is not yet known for certain why this happened, although potential factors include wheel wear and track design."

The report also said "Cracks were also found after examination of ScotRail's Class 385 and Southeastern's Class 395 trains."

So are our operating conditions different from those in Japan?

Jonathan

[St Enodoc]

2 minutes ago, corneliuslundie said:

The web report says both in different places:

"The ORR investigation found the design of the trains complied with existing standards but that corrosion cracks were found on lifting points - which allow carriages to be raised during maintenance work - resulting from the use of a particular type of aluminium, which was corroded by salt in the air.

It said fatigue cracking was caused by the "trains experiencing greater loads from train movement than allowed for in the original design"."

So the aluminium was not suitable for use on trains on coastal routes and the standard was not adequate, since the report says that standards were met.

Also from the BBC website:

"It is not yet known for certain why this happened, although potential factors include wheel wear and track design."

The report also said "Cracks were also found after examination of ScotRail's Class 385 and Southeastern's Class 395 trains."

So are our operating conditions different from those in Japan?

Jonathan

Stress corrosion cracking is caused by a combination of mechanical stress and  a corrosive environment, just like it says on the tin!

 

See, for example: http://www.totalmateria.com/Article17.htm

[Mallard60022]

6 minutes ago, corneliuslundie said:

The web report says both in different places:

"The ORR investigation found the design of the trains complied with existing standards but that corrosion cracks were found on lifting points - which allow carriages to be raised during maintenance work - resulting from the use of a particular type of aluminium, which was corroded by salt in the air.

It said fatigue cracking was caused by the "trains experiencing greater loads from train movement than allowed for in the original design"."

So the aluminium was not suitable for use on trains on coastal routes and the standard was not adequate, since the report says that standards were met.

Also from the BBC website:

"It is not yet known for certain why this happened, although potential factors include wheel wear and track design."

The report also said "Cracks were also found after examination of ScotRail's Class 385 and Southeastern's Class 395 trains."

So are our operating conditions different from those in Japan?

Jonathan

That is exactly what a Chief Hitachi Engineer told me a couple of weeks back when we had a chat at Retford Station as he was waiting to go to discuss this in London. Very interesting hearing his info. he hinted that the Units were a bit 'lightweight' in Constuction but dead easy to replace Bogie Units....at a large price of course.

Average weight of British passengers was also a tiny factor!!!!!! WE are seemingly more lardy than Japanese folk.

[4630]

It will be interesting to see how the findings from the ORR investigation informs any ongoing discussion regarding the financial liability for the non-availability and repair of the units.

 

I would surmise that the £ or Yen numbers would be pretty chunky from a balance sheet perspective, or DfT budget too for that matter if some of the financial liability ends up being shared.

[Jonboy]

How much salt in the air would the chassis have been exposed to when shipping from Japan?

[rodent279]

On 07/04/2022 at 12:11, St Enodoc said:

Stress corrosion cracking is caused by a combination of mechanical stress and  a corrosive environment, just like it says on the tin!

 

See, for example: http://www.totalmateria.com/Article17.htm

So, if I understand correctly:-

• Alloys of this kind are composed of different types of metals , e.g. Aluminium, Copper, other metals & rare earths
• The molecular structure of these alloys is such that there are granular "clumps" of the various component materials 
• These granules, under the right conditions, can form electrolytic cells , much as when two dissimilar metals are placed in contact.
• The presence of liquid and salts can act as an electrolyte, which causes destructive corrosion.
• This can cause fractures to occur along lines of stress when mechanical forces are applied.

Edited April 8, 2022 by rodent279

[RJS1977]

Edited April 7, 2022 by RJS1977

[rodent279]

What's the latest on this? Has any further analysis been done on the cause of the cracking, and what can be done to avoid it?

[DY444]

On 05/11/2022 at 08:02, rodent279 said:

What's the latest on this? Has any further analysis been done on the cause of the cracking, and what can be done to avoid it?

 

There's a repair programme being put in place to fix it.  I believe every set delivered so far will be done and there are a couple of GWR sets at Eastleigh as the guinea pigs for the programme.

[david.hill64]

On 08/04/2022 at 02:09, rodent279 said:

So, if I understand correctly:-

• Alloys of this kind are composed of different types of metals , e.g. Aluminium, Copper, other metals & rare earths
• The molecular structure of these alloys is such that there are granular "clumps" of the various component materials 
• These granules, under the right conditions, can form electrolytic cells , much as when two dissimilar metals are placed in contact.
• The presence of liquid and salts can act as an electrolyte, which causes destructive corrosion.
• This can cause fractures to occur along lines of stress when mechanical forces are applied.

Not quite. 

 

Alloys are combinations of metals which form a common crystal structure.

The structure forms on solidification by grains growing from nuclei in the melt. Eventually these grains meet up so there is a boundary between grains of different orientation. The grains themselves have similar chemical composition and do not act as electrolytic cells in the same way as you get, for example by mixing aluminium and steel components in the same vehicle.

The grain boundaries are a source of weakness in the alloys and in certain materials (eg aluminium alloys) are prone to rupture in the presence of a corrosive medium and stress.

 

Metallurgists make a lot of effort to negate the effects of the grain boundaries and various mechanical working, heat treatments and added elements can be effective at improving strength depending on the base alloy.

 

In certain critical applications - eg aero engines - parts are grown as a single crystal to ensure that there are no grain boundary effects.

Edited November 8, 2022 by david.hill64
typo

[Bucoops]

On 08/11/2022 at 07:37, david.hill64 said:

Not quite. 

 

Alloys are combinations of metals which form a common crystal structure.

The structure forms on solidification by grains growing from nuclei in the melt. Eventually these grains meet up so there is a boundary between grains of different orientation. The grains themselves have similar chemical composition and do not act as electrolytic cells in the same way as you get, for example by mixing aluminium and steel components in the same vehicle.

The grain boundaries are a source of weakness in the alloys and in certain materials (eg aluminium alloys) are prone to rupture in the presence of a corrosive medium and stress.

 

Metallurgists make a lot of effort to negate the effects of the grain boundaries and various mechanical working, heat treatments and added elements can be effective at improving strength depending on the base alloy.

 

In certain critical applications - eg aero engines - parts are grown as a single crystal to ensure that there are no grain boundary effects.

 

One of my lecturers at uni was heavily involved in the development of single crystal turbine blades.

[ess1uk]

On 07/11/2022 at 16:40, DY444 said:

 

There's a repair programme being put in place to fix it.  I believe every set delivered so far will be done and there are a couple of GWR sets at Eastleigh as the guinea pigs for the programme.

How long per set?

or will it vary on condition?

[DY444]

12 hours ago, ess1uk said:

How long per set?

or will it vary on condition?

 

AIUI they are all getting the same modification because it's a systemic fault which worsens over time and so all are susceptible to it even those that have not shown any cracks to date.  No idea how long each set will take but the first one or two will no doubt take longer whilst they figure out the nitty-gritty of the repair process.  I saw a report that it is expected to take about 5 years to do the whole lot.

[great central]

Wonder who cops the bill?

Given they were specified by the Dft, it wouldn't surprise me if fell to the poor old taxpayers again.

[DY444]

18 hours ago, great central said:

Wonder who cops the bill?

Given they were specified by the Dft, it wouldn't surprise me if fell to the poor old taxpayers again.

 

I suspect Hitachi is bearing the cost.  AIUI it was provided with detailed information about the range of operating conditions and track characteristics to be expected and, whilst I don't profess to have any expertise in metallurgy and the science of materials, it appears the grade of aluminium chosen for critical components was not the best all rounder for the anticipated service environment.  So my reading of it is that Hitachi chose materials and manufacturing techniques which didn't suit the application.  There were also reports that the DfT was furious and its lawyers went in with all guns blazing and lurid coloured highlighter all over the contract clauses pertaining to product quality.  I see it clearly as product not fit for purpose so manufacturer pays and I think the DfT does too. 

 

Having said that there has been no information about who is bearing the cost but there have been multiple reports that Hitachi is both very defensive and extremely conscious of its reputation so it may be there has been a quid pro quo; Hitachi pays if the DfT stays quiet.    

Edited November 15, 2022 by DY444

[Davexoc]

So are any of the more recent sets going to have to go through the same process? or has there been an upgrade in the interim?  Thinking Lumo and soon to come Avanti sets....

[DY444]

9 hours ago, Davexoc said:

So are any of the more recent sets going to have to go through the same process? or has there been an upgrade in the interim?  Thinking Lumo and soon to come Avanti sets....

 

AIUI Lumo yes but the Avanti and EMR sets will be delivered with the revisions incorporated.

[rodent279]

1 minute ago, DY444 said:

 

AIUI Lumo yes but the Avanti and EMR sets will be delivered with the revisions incorporated.

What are the revisions? Just a different aluminium spec, or physical size & shape of parts?