GWR Class 800

[najaB]

Forgive me for playing devil's advocate but is this 110% testing requirement actually a thing now?

I can't see how it wouldn't be. Would you want to travel at 125mph on a train whose design hasn't been proven to be safe at 126mph?

 

[JN114]

I can't see how it wouldn't be. Would you want to travel at 125mph on a train whose design hasn't been proven to be safe at 126mph?

Id be perfectly comfortable with travelling on a train at 125mph if it had been tested at 125mph yes. I draw no additional comfort from whether or not it has been deliberately tested at speeds exceeding the maximum it would ordinarily achieve in its stated operating envelope.

My cynicism stems from having never seen mention of, or heard of this kind of testing in anything comissioned in the last 15 years - it was mentioned in this thread then lo and behold it also appears in the railway press shortly afterward. It reads almost as if they read it here, published it as fact, and now that publication is being cited as evidence that such testing takes place.

I'm happy to be proved wrong, and I'd be interested to hear if it does actually happen, but it's being bandied around like gospel at the moment when there isn't a shred of evidence for it.

 

[najaB]

Id be perfectly comfortable with travelling on a train at 125mph if it had been tested at 125mph yes. I draw no additional comfort from whether or not it has been deliberately tested at speeds exceeding the maximum it would ordinarily achieve in its stated operating envelope.

The key word there being 'ordinarily'. However, as we well know, there are circumstances under which a train will exceed 125mph - e.g. speedometers aren't exact - hence why they are tested with an appropriate safety margin.

As to why you don't recall hearing about other classes being tested it could be any one of a number of reasons: the testing happened but wasn't considered newsworthy, they were derivatives of existing classes hence the safety case was done by analysis, the running gear had already been tested before, or maybe you just never read the articles.

 

[D365]

I'm fairly confident that I've heard of the Class 321 and Class 365 being tested to 110% overspeed on AC when new.

 

[AM9]

I can't see how it wouldn't be. Would you want to travel at 125mph on a train whose design hasn't been proven to be safe at 126mph?

So a train (or any vehicle) is tested at its maximum legal speed when new. That doesn't mean that three years later, just before it is due for a major overhaul that it is safe to do that maximum speed. If you drive a car, what maximum speed would you like that to be certified safe at?

 

[notadriver]

Trains are regularly checked to ensure they are safe to operate at their maximum speed no matter where they are in their life cycle. To suggest a train nearing overhaul is unsafe to do it's rated top speed is foolish and might put people travelling off trains. After all HSTs are still doing 125 mph and they are nearing 40 years of age. I wouldn't trust a 40 year old coach to run at that speed.

As for cars the UK limit is 70 mph so allowing 10 percent perhaps 80 mph is the most it should be certified to be safe at. Yes i know modern cars have top speeds of in excess of 100 mph but in the UK at least this is not allowed in public roads.

 

[najaB]

So a train (or any vehicle) is tested at its maximum legal speed when new.

No. It is about validating the design. Each individual vehicle is then maintained according to that design and hence should be safe. If there was a design flaw then it doesn't matter how well maintained the vehicles are.

 

[asylumxl]

Am I correct in my assumption that if/when these operate at 140mph, only then will overspeed tests be conducted at 154mph?

 

[WatcherZero]

Conflicting accounts, one person claims they wont be because of incompatible pan with HS1 overheads, another says a 155mph test run date has been planned.

 

[Peter Sarf]

Conflicting accounts, one person claims they wont be because of incompatible pan with HS1 overheads, another says a 155mph test run date has been planned.

Hopefully by the time the 140mph+ tests are required the GWML electrification will be ready.

 

[AM9]

No. It is about validating the design. Each individual vehicle is then maintained according to that design and hence should be safe. If there was a design flaw then it doesn't matter how well maintained the vehicles are.

It seems that I didn't make it clear enough in my post as I was answering JN114's questioning the current practice and agreeing with your assertion that testing beyond the normally expected maximum speed is the correct thing to do. I wasn't suggesting that trains were in any respect 'unsafe' when operated within an appropriate maintenance regime.
What I meant was that the maximum 'legal' (maybe the wrong word) speed for a train was that which it could be expected to acheive on the services that it is deployed on so that would be unsuitable as a maximum speed under optimum test conditions. The 10% excess speed testing is a sensible safety margin that as has been mentioned, allows for an obvoius shortfall, speedometer uncertainty. The margin also allows for a number of other factor that may not be a matter of life and death but can have an impact of comfort, reliability and wear and tear of both rolling stock and infrastructure. Such things as suspension dynamics and transmission noise spring to mind.
As observed by asylumxl, if the stock is moved to another route or the route is upgraded, as might be the case when the GWML is cleared for 140mph, the margin should be re-established by further tests at 110% of its new service maximum.

 

[najaB]

It seems that I didn't make it clear enough in my post...

Or I fail at comprehension.

 

[themiller]

The 110% speed testing is a contractual condition. The client wants the manufacturer to prove that the 'goods' are fit for use as defined in the contract. It's very much a case of the client making the manufacturer put his money where his mouth is. If the 110% test was not carried out before putting the trains into service, it may affect whether the test causes a liability on the manufacturer some months/years down the line - e.g. if the manufacturer went to the wall. I would have though that the manufacturer could charge for issues discovered after 2years+ in service whereas they would be liable before acceptance (depending on the terms of any guarantee).

 

[RobShipway]

Okay, let's go back in history a bit to 1972 when the APT-E was tested between Swindon and Reading. This achieved 152.23mph on testing using Gas Turbine power.

The ATP-P trains which was the pre - production sets of the Advanced passnger train where designed to work in service at 125mph, but where tested on the WCML at 155mph. The APT-P trains years later led to both the class 91 trains and the class 390 Pendolino's.

Now again the class 91's only run at about 125mph, but have in the shape of 91110 been testing at 161.7 mph back in September 1989 prior to introduction.

Now given the above, it will be the same with both class 800/801 trains within their testing. I have no doubt that we will hear the the class 800 Electro - Diesels have been able to reach speeds up to 160mph either on HS1, East Coast main line and if or when the GWR is finally electrified.

 

[NotATrainspott]

Okay, let's go back in history a bit to 1972 when the APT-E was tested between Swindon and Reading. This achieved 152.23mph on testing using Gas Turbine power.

The ATP-P trains which was the pre - production sets of the Advanced passnger train where designed to work in service at 125mph, but where tested on the WCML at 155mph. The APT-P trains years later led to both the class 91 trains and the class 390 Pendolino's.

Now again the class 91's only run at about 125mph, but have in the shape of 91110 been testing at 161.7 mph back in September 1989 prior to introduction.

Now given the above, it will be the same with both class 800/801 trains within their testing. I have no doubt that we will hear the the class 800 Electro - Diesels have been able to reach speeds up to 160mph either on HS1, East Coast main line and if or when the GWR is finally electrified.

However, weren't all these speed records on trains with power cars and a shortened rake of carriages? It's not surprising that a Class 91 locomotive designed to take 9 Mk4 carriages to 140mph can manage much higher speeds if it's not dragging as many. Multiple units won't be able to reach the same top speed in experimental conditions because the power to weight ratio is going to be roughly the same regardless of train length.

 

[najaB]

However, weren't all these speed records on trains with power cars and a shortened rake of carriages? It's not surprising that a Class 91 locomotive designed to take 9 Mk4 carriages to 140mph can manage much higher speeds if it's not dragging as many.

I didn't take Robbies' post to be about record setting per se, rather it was about the fact that they were all tested to their expected service speed plus a margin.

 

[JN114]

But Robbies they were all runs with the explicit purpose of setting the British/World speed record for a Gas Turbine/Electric/Diesel train.

I will happily believe that it would be a contractual requirement, if anyone would actually cite where the claims they're making come from. There's certainly no mention I can see of a 110% testing requirement in the DfT spec (which is very thorough in every other area).

 

[najaB]

I will happily believe that it would be a contractual requirement, if anyone would actually cite where the claims they're making come from. There's certainly no mention I can see of a 110% testing requirement in the DfT spec (which is very thorough in every other area).

I believe it is specified in EN 14363 but I'm not willing to pay £240 to find out. Does anyone have access?

 

[LNW-GW Joint]

But Robbies they were all runs with the explicit purpose of setting the British/World speed record for a Gas Turbine/Electric/Diesel train.
I will happily believe that it would be a contractual requirement, if anyone would actually cite where the claims they're making come from. There's certainly no mention I can see of a 110% testing requirement in the DfT spec (which is very thorough in every other area).

HST, APT and Class 91 were all BR showing off its shiny new trains and technology.
By contrast, today's setup is all about safety cases and train acceptance on various routes.
In any case the contract is quite different - nobody is "buying" a new train.
They remain in Hitachi/Agility ownership, who are seeking clearance to operate them on NR metals (at 125 mph).
In any case Eurostar has the UK speed record, which will not be challenged by IEP.
140mph operation is of no interest until ERTMS is fitted, which is probably 5 years away.

 

[Philip Phlopp]

and if or when the GWR is finally electrified.

And another one to run past us again.

 

[ainsworth74]

I believe it is specified in EN 14363 but I'm not willing to pay £240 to find out.

Well that just shows a distinct lack of dedication to the cause. No one is angry with you but we are all a bit disappointed

 

[najaB]

I believe it is specified in EN 14363 but I'm not willing to pay £240 to find out. Does anyone have access?

I've managed to find a freely available document that references the requirement:

Additional test conditions to be fulfilled on each of the individual track sections making up these test
zones are the following:
- on zone 1: test speed shall be Vlim + 10% (tolerance +/- 5 km/h)

 

[Domh245]

I believe it is specified in EN 14363 but I'm not willing to pay £240 to find out. Does anyone have access?

Yes, a university with a subscription to BS online is a wonderful thing. Having a look through EN14363, I think I've found the relevant section, so I'll leave a screenshot of the relevant section here for all to argue over.

 

[Philip Phlopp]

I believe it is specified in EN 14363 but I'm not willing to pay £240 to find out. Does anyone have access?

It is.

The European Railway Agency's EN14363:2005 modifications and clarifications document, which everybody should have access to, specifically states

maximum test speed (service speed +10%) has been tested over track of a suitable length and quality to demonstrate stability

That's clarifying vmax = 1,1 x vadm from the EN 14363 document shown in the post above. In this case vmax is maximum velocity, and vadm is (maximum) admissible velocity. 1,1 times is the same as 110% for anybody a little uncertain about the wording of these things, it's just a very metric and EU way of saying things.

 

[RobShipway]

However, weren't all these speed records on trains with power cars and a shortened rake of carriages? It's not surprising that a Class 91 locomotive designed to take 9 Mk4 carriages to 140mph can manage much higher speeds if it's not dragging as many. Multiple units won't be able to reach the same top speed in experimental conditions because the power to weight ratio is going to be roughly the same regardless of train length.

The answer to your question is probably yes for the most part, but is that any different to the shortened class 800's that are running on Old Dalby test track?

The trains mentioned in my previous post where showing even if they were within a shortened formation, what the trains would be able to do and then some.

 

[Philip Phlopp]

The answer to your question is probably yes for the most part, but is that any different to the shortened class 800's that are running on Old Dalby test track?

The trains mentioned in my previous post where showing even if they were within a shortened formation, what the trains would be able to do and then some.

What shortened IEPs at Old Dalby ?

I feel I've missed something important here.

 

[JN114]

Thank you for clarifying

 

[NotATrainspott]

The answer to your question is probably yes for the most part, but is that any different to the shortened class 800's that are running on Old Dalby test track?

The trains mentioned in my previous post where showing even if they were within a shortened formation, what the trains would be able to do and then some.

What shortened IEPs at Old Dalby ?

I feel I've missed something important here.

The Old Dalby trains won't be 'shortened', they'll be the standard half-length 5 car sets that will be used day-in, day-out across the network.

Their power-to-weight ratio will be approximately the same as any other length of IEP because the amount of power scales roughly linearly with length, as extra carriages will add more electric motors and in the self-powered versions, more diesel engines. That's quite unlike a power car set up, where the power to weight ratio of an HST would be massively improved by removing carriages and so it would be easy to massively exceed day-to-day speeds achieved with full rakes.

 

[jimm]

The Old Dalby trains won't be 'shortened', they'll be the standard half-length 5 car sets that will be used day-in, day-out across the network.

Their power-to-weight ratio will be approximately the same as any other length of IEP because the amount of power scales roughly linearly with length, as extra carriages will add more electric motors and in the self-powered versions, more diesel engines. That's quite unlike a power car set up, where the power to weight ratio of an HST would be massively improved by removing carriages and so it would be easy to massively exceed day-to-day speeds achieved with full rakes.

I think the reference to a shortened train means 800101, which was delivered from Japan in May as a five-car set, with the other four coaches to bring it up to its full nine-car formation coming on another ship in August.

 

[Peter Sarf]

What shortened IEPs at Old Dalby ?

I feel I've missed something important here.

EDIT
What "jimm" said immediately above (I just noticed it there )
endEDIT

If I remember correctly one of the bi-mode IEPs was delivered to a test track as five cars and subsequently five four extra vehicles were delivered. I cannot remember whether those extra cars have been inserted but they belonged in the right number range to be the something like the 2rd to 5th (I corrected to) 3rd-6th vehicles in a 9-car unit.

EDIT :-
Found my scrap of paper
800101 arrived at Asfordby (if I have the name right) as five car
formed :-
811101
812101_
817101
818101
819101

Then
813101
814101
815101
816101
arrived - I just do not know if they have been added yet but I think they have.

Notice how logical the vehicle numbering is these days, I like that. But it will be spoilt and obvious if (when) a mongrel unit appears !. For example three of the early 350s have swapped coaches.

end EDIT

BUT given they have distributed power then the power to weight ratio running as a diesel would be largely the same. However whilst running on electric from the overhead they would have a favourable power to weight ratio if they were a 9-car reduced to 5-car. That's assuming the electric traction bit is all in the end cars !.

However for safety checks I suppose a shortened unit is allowable provided it can be demonstrated that there is no additional equipment in one of the missing coaches that needed validating. Remember that for an over-speed test the point is to validate the DESIGN by over doing it on one example of the train in question. They do not have to test all the trains. I understand this as a test to ensure the DESIGN has no flaws in it - this is not a test of how well each train/unit/coach HAS been maintained.