GWR Class 800

Mikey C said:

They are very unobtrusive, and (visually) pretty clean too judging from the lack of smoke.

But ridiculous when GWR are operating them in diesel mode under the wires, if nothing else surely this much affect timetabling seeing that they can only do 100 in diesel mode

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So even if the train has an issue with the pantograph but is fully functional as a diesel train, they just shouldn't bother sending it out and leave a big hole in the timetable then?

As has been noted back up the thread, there have been days when pretty much all services have been able to operate on electric power where it is available, then there have been days when several sets have had to run on diesel due to faults of one sort or another, such as pantograph problems.

The IETs can do a whole lot more than 100mph on diesel, like 120mph+, which was all covered in great detail on this forum months ago. This is why the 800s have been able to keep up with HST timings since October 2017, despite the delays to the Great Western electrification work.

jimm said:

The IETs can do a whole lot more than 100mph on diesel, like 120mph+, which was all covered in great detail on this forum months ago. This is why the 800s have been able to keep up with HST timings since October 2017, despite the delays to the Great Western electrification work.

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Great Western timings are rubbish anyway with a shed load of padding in them - HSTs are more than capable of bettering the current timetable. The default response to poor performance on GW historically has been to add more padding to the timetable rather than properly address the underlying issue.

jimm said:

So even if the train has an issue with the pantograph but is fully functional as a diesel train, they just shouldn't bother sending it out and leave a big hole in the timetable then?

As has been noted back up the thread, there have been days when pretty much all services have been able to operate on electric power where it is available, then there have been days when several sets have had to run on diesel due to faults of one sort or another, such as pantograph problems.

The IETs can do a whole lot more than 100mph on diesel, like 120mph+, which was all covered in great detail on this forum months ago. This is why the 800s have been able to keep up with HST timings since October 2017, despite the delays to the Great Western electrification work.

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But why are they having so many problems operating in electric mode?

After all the Diesel engines aren’t there to cover for unreliability elsewhere

Does Hitachi receive full payment for having a train in service as part of there contract if it is only capable of being run in diesel mode only?

Seems like they would have lost a load of money if the Bi-Mode conversions hadn't taken place. Or maybe not with how badly the contract is rumoured to have been written.

I think the question may have been posted earlier but I couldn't see an answer anywhere. If I have missed it my apologies.

Clarence Yard said:

The sequence was some years apart. The removal of the buffet cars was a Dean Finch move - he hated them. He could never get that you stuck the cost of them into the ticket price, not try to make them profitable on their own accord.

Enter Andrew Haines and the introduction of the mini-buffets, which at least mean’t you could offer a catering service on all sets, without caning the seating capacity. The design was a total nick from Greater Anglia.

Several years later and we have the too much first class, not enough standard issue. But there weren’t enough ordinary “day” coaches left to “convert and insert” so the redundant buffet cars had to go into the conversion mix.

Iirc, the time between the decision making process for the TSMB and then the other conversions was about 6-7 years.

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What I don't properly understand is why they didn't put the off lease buffet cars back into the formations, either as full size or conversions to mini buffets.

Mikey C said:

But why are they having so many problems operating in electric mode?

After all the Diesel engines aren’t there to cover for unreliability elsewhere

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I can't get my head round it either. Imagine if Hornsey announced they were 10 313s short. That would mean half the service running three cars instead of six. I'm not aware of that ever happening but maybe it did when they were new.

Went on a 800 today, and the condition of them is appalling for a new train. I've never been on a train with so many rattles and squeeks!

cactustwirly said:

Went on a 800 today, and the condition of them is appalling for a new train. I've never been on a train with so many rattles and squeeks!

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This is completely anecdotal, but I thought similar when the 390s were new, with annoying rattles presumably from pieces of trim. I've not noticed it for years now. I've no idea what's changed, it seems counter-intuitive that something would get quieter over time!

jimm said:

The IETs can do a whole lot more than 100mph on diesel, like 120mph+, which was all covered in great detail on this forum months ago.

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The Rail Performance Society suggests 112mph for an 800 and 119 for an 802.

John Clausen said:

What I don't properly understand is why they didn't put the off lease buffet cars back into the formations, either as full size or conversions to mini buffets.

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Seat totals and it was cheaper to convert the ordinary coaches than convert the buffet cars. It was an option that was looked at.

Mikey C said:

But why are they having so many problems operating in electric mode?

After all the Diesel engines aren’t there to cover for unreliability elsewhere

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Swansea can’t deal with electric repairs so if it is isolated on arrival, it will go out on diesel. As the sets are currently operating on HST times, no big deal. But when the new timetable comes in December, it will be so Q paths will have to be put in to swap units out between Stoke Gifford and Maliphant. Hitachi are also currently having some issues with their maintenance and repair throughput at both North Pole and Stoke Gifford which means too many are coming off with GU’s isolated or no electric because they haven’t sorted the fault. That will also be an issue come December. There is a rebate mechanism in the contract but I can’t get into that here.

As far as the comment about padding is concerned, the current timetable mainly reflects the fact that the Western is a far more crowded railway than it was, with more stops on high speed services. Trains are being generally slowed to make them fit, not for some vague performance benefit. The days when the waves used to part for the HST have gone, the GWR Class 1 trains are just one set of trains to be treated equally with all the others when it comes to timetabling.

I don't know if this is true or not, but I've heard it so many times over the years I've just assumed it is - that a train certified for x mph maximum speed must be able to do 10% above x.

Is that true or not? Do (can?) bi-mode trains have multiple maximum allowed speeds or just one?

mmh said:

I don't know if this is true or not, but I've heard it so many times over the years I've just assumed it is - that a train certified for x mph maximum speed must be able to do 10% above x.

Is that true or not? Do (can?) bi-mode trains have multiple maximum allowed speeds or just one?

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It is correct that trains are generally certified to 10% over their planned in service maximum. The IETs are designed for 140, so I'd imagine they've been tested to 154mph.

There's no way they'd manage that on Diesel so I assume the test is simply to prove the train is safe at those speeds rather than it can actually achieve them.

hexagon789 said:

The Rail Performance Society suggests 112mph for an 800 and 119 for an 802.

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I had an 800 reach 125 in diesel mode just yesterday. 800016 + 800013. And it’s not the first time.

Mintona said:

I had an 800 reach 125 in diesel mode just yesterday. 800016 + 800013. And it’s not the first time.

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I still don't get the impression that's possible. It's long been stated that they cannot keep pace with an HST on diesel both acceleration and speed wise.

Mintona said:

I had an 800 reach 125 in diesel mode just yesterday. 800016 + 800013. And it’s not the first time.

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What service was that on? I had that pair from Reading to Swindon (think it was 19.12 from Reading) and they were going to Bristol Parkway so assume they were shuttling between there and Paddington all day? Definitely on electric at Reading and Swindon.

hexagon789 said:

I still don't get the impression that's possible. It's long been stated that they cannot keep pace with an HST on diesel both acceleration and speed wise.

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It definitely is. Between Bristol Parkway and Swindon, Swindon and Didcot Parkway and Swindon and Chippenham it is common to reach 125 in diesel mode.

Richard Scott said:

What service was that on? I had that pair from Reading to Swindon (think it was 19.12 from Reading) and they were going to Bristol Parkway so assume they were shuttling between there and Paddington all day? Definitely on electric at Reading and Swindon.

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0930 Paddington - Bristol TM.

Mintona said:

It definitely is. Between Bristol Parkway and Swindon, Swindon and Didcot Parkway and Swindon and Chippenham it is common to reach 125 in diesel mode.

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We'll have to disagree on that, nothing I've seen thus far suggests 125mph is possible on level track in diesel-mode.

hexagon789 said:

We'll have to disagree on that, nothing I've seen thus far suggests 125mph is possible on level track in diesel-mode.

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Those sections aren’t level track. They’re all slightly downhill. You never said that in your first post, you just said the top speed was 112mph, which is wrong.

Mintona said:

Those sections aren’t level track. They’re all slightly downhill. You never said that in your first post, you just said the top speed was 112mph, which is wrong.

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112mph on level track for an 800, if I didn't specify 'level track' my apologies but I thought that was implied.

hexagon789 said:

112mph on level track for an 800, if I didn't specify 'level track' my apologies but I thought that was implied.

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The high speed performance of a 5+5 800 on diesel power should be significantly greater than that of a single 5-car on diesel power since the rear unit is in the slipstream of the front unit (unless the control systems have been programmed to use the potential speed advantage of a 5+5 for fuel economy and lower maintenance rather than speed). Does your figure refer to a single 5-car, a 9-car or a 5+5 formation?

hexagon789 said:

I still don't get the impression that's possible. It's long been stated that they cannot keep pace with an HST on diesel both acceleration and speed wise.

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We have been monitoring and recording performance of the 800's from introduction, and it is clear that they can and do reach 125mph on downward gradients.

On reasonably level track - for example the very lightly graded sections between Paddington and Reading - a class 800's maximum speed appears to be around 119mph - with 113mph on the uphill incline between Dicot and Swindon. In the up direction from Swindon towards Didcot they can achieve 125mph downhill.

The 802's on the other hand can maintain 125 mph on level track - and it is believed more would be possible if the track allowed more than 125mph! This is all to do with how the trains -generator units power output is managed.

We understand the Class 800's power units are now designed to generate the full 940 horses from standstill, as do the 802's. But power is understood to be ramped back to the 750bhp setting as the train starts picking up speed.

The Class 802's are also understood to start out delivering 940hp but also ramp back power too - but by a lesser amount - hence their greater acceleration rate than a Class 800.
Gradients do seem to affect the rate of acceleration - and so we can conclude there isn't a fixed acceleration rate control - but rather how the trains traction computers are programmed to apply a set amount of power at a given speed.

Both class 800 and 802 acceleration rate is quicker than an average driven HST from rest to around 30-40mph - but then as we have said before the HSTs acceleration between 40mph and 125mph is greater, and in a drag race it would eventually catch up with and pass both the 800 and 802.

This doesn't really seem to be a problem on lines where the speed limits are 100mph or less, but becomes an issue where sustained 100mph+ running is needed. And also, it has been common to see Class 800's and 802's running with generator units (engines) out -which adversely affects performance.

if anyone wants to look at some more in depth information on Class 800 performance and comparisons to HST's, the Railway Performance Society have published some free data on their website for anyone interested to download free of charge.

The link is here .. http://www.railperf.org.uk/index/iet

The best summary document is this one ....http://railperf.org.uk/docs/802intro.pdf

43096 said:

Great Western timings are rubbish anyway with a shed load of padding in them - HSTs are more than capable of bettering the current timetable. The default response to poor performance on GW historically has been to add more padding to the timetable rather than properly address the underlying issue.

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The current timetable seems to be built around 3 minute headways - but in practice it seems impossible for one train to follow another out of Paddington and into Reading 3 minutes later without some kind of signal check - even when train A runs cleanly into its assigned platform. I don't know how long it takes for the block sections to clear in order for the route and signals to be set for the following train, but what i do know, is that the following train always seems to encounter cautionary signals further back towards Twyford causing it to brake earlier and extend its journey time into Reading. Also the fact that Reading starter is always red causes a much more cautionary approach due to ATP and TPWS issues as well as defensive driving rules! Maybe the timetable would be better based around 3.5 to 4 minute headways instead?
Also in the current timetable you have to factor in Heathrow Express services running at only 100mph between 125mph services. Surely a few additional IET's or 125mph capable EMUS should have been ordered for the airport service to maximise track capacity? the 387's can technically run at 110mph which could potentially reduce the time difference between Paddington and Airport Jn, but the pantograph positioning means 100mph is likely to remain the maximum until the OLE is improved!
And of course we still have some 90mph Turbos running up and down the main line too - which isn't great for track capacity either.
From Reading back into Paddington you have the issues of slotting in the mainline services in between the Heathrow Express paths. If one or the other is running late, delays occur en route extending the journey time. I understand the need for some 'padding' at those intersections. I understand the wisdom in adding a 2 or 3 minute stop at Reading to allow a late running train from the West Country to be able to recoup any lost minutes, and therefore give the service a fighting chance to hit the correct slot into Paddington without delaying other services. But quite often that doesn't seem to solve the problem. So in some respects it does seem a waste of time adding it in.
The amount of flat junctions also seems to be an issue, and again, i see the wisdom of adding some padding to give all trains a chance of hitting those junctions at their allocated times. But unless millions or possible billions are spent on building flyovers or diveunders, you are always going to have potential conflicts and the need for 'padding' to try and regulate the services crossing those junctions.
With regards to Paddington station throat and track layout, am i right in believing that operationally it is inflexible enough to allow robust 3 minute headways on arrivals and departures? I always seem to be delayed coming into Paddington - even when Open Train Times maps show very little activity around.

Oh dear it seems 1a85 was formed of just 1 x 5 car 802 on good Friday as far as Plymouth. I drove the same service earlier in the week and the passenger count said 450 passengers by liskeard, so must of been extremely cosy on good Friday packed into a 5 car!!! Just another example where the west is stitched up by using none proper length trains....

JamesRowden said:

The high speed performance of a 5+5 800 on diesel power should be significantly greater than that of a single 5-car on diesel power since the rear unit is in the slipstream of the front unit (unless the control systems have been programmed to use the potential speed advantage of a 5+5 for fuel economy and lower maintenance rather than speed). Does your figure refer to a single 5-car, a 9-car or a 5+5 formation?

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'Form' drag (that caused be turbulent flow along the undersides, sides and roofs of the train as well as the turbulence caused in the inter-coach gaps and running gear) is roughly proportional to train length. There will be some additional drag where the two units are coupled as the air flows into and out of the space over the noses. The only thing that will be saved with a longer train is the drag over the nose of the leading coach as that occurs only once. But the drag from this source will be proportionally reduced as the train gets longer so the performance of a longer train will not be significantly better.

Railperf said:

We have been monitoring and recording performance of the 800's from introduction, and it is clear that they can and do reach 125mph on downward gradients. On reasonably level track - for example the very lightly graded sections between Paddington and Reading - around 113mph seemed to be their maximum. The 802's on the other hand reach around 119mph on level track. This is all to do with how the trains -generator units power output is managed. We understand the 800's power units are designed to generate the full 940 horses from standstill, as do the 802's. But power is understood to be ramped back to the 750bhp setting as the train starts picking up speed. The 802's are also understood to ramp back power too - but by a lesser amount - hence their greater acceleration rate than an 800.
Gradients do seem to affect the rate of acceleration - and so we can conclude there isn't a fixed acceleration rate control - but rather how the trains traction computers are programmed to apply a set amount of power at a given speed.
Both class 800 and 802 acceleration rate is quicker than an average driven HST from rest to around 30-40mph - but then as we have said before the HSTs acceleration between 40mph and 125mph is greater, and in a drag race it would eventually catch up with and pass both the 800 and 802.
This doesn't really seem to be a problem on lines where the speed limits are 100mph or less, but becomes an issue where sustained 100mph+ running is needed. And also, it has been common to see Class 800's and 802's running with generator units (engines) out -which adversely affects performance.

if anyone wants to look at some more in depth information on Class 800 performance and comparisons to HST's, the Railway Performance Society have published some free data on their website for anyone interested to download free of charge.

The link is here .. http://www.railperf.org.uk/index/iet

The best summary document is this one ....http://railperf.org.uk/docs/802intro.pdf

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That is precisely the document I was going off of!

JamesRowden said:

The high speed performance of a 5+5 800 on diesel power should be significantly greater than that of a single 5-car on diesel power since the rear unit is in the slipstream of the front unit (unless the control systems have been programmed to use the potential speed advantage of a 5+5 for fuel economy and lower maintenance rather than speed). Does your figure refer to a single 5-car, a 9-car or a 5+5 formation?

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You'd need to see the document Railperf linked to for that information.

coppercapped said:

'Form' drag (that caused be turbulent flow along the undersides, sides and roofs of the train as well as the turbulence caused in the inter-coach gaps and running gear) is roughly proportional to train length. There will be some additional drag where the two units are coupled as the air flows into and out of the space over the noses. The only thing that will be saved with a longer train is the drag over the nose of the leading coach as that occurs only once. But the drag from this source will be proportionally reduced as the train gets longer so the performance of a longer train will not be significantly better.

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I think that all the other sources of resistance that you mention will be insignificant compared to that huge volume of low pressure at the rear of train sucking it backwards. You can provide some real numbers to prove that I'm wrong if you have them.

If I assume a rough example of there being normal air pressure at the front of the train and a vacuum at the back, the pressure difference between the two will be 100kN per square meter. If I guess that the train has 6 square meters cross sectional area we multiply those to get 600kN. If we multiply that by 44 meters per second (about 100mph) we get 26MW. That's significantly more than the output power of the train (120kW per axle), so obviously there is still reasonable air pressure behind the train, but it shows how significant the air pressure behind the train could potentially be.

43096 said:

Great Western timings are rubbish anyway with a shed load of padding in them - HSTs are more than capable of bettering the current timetable. The default response to poor performance on GW historically has been to add more padding to the timetable rather than properly address the underlying issue.

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Which underlying issue might that be? That GWR is operated by First Group?

If you want to pretend we still live in October 1976, that's up to you, but the world has changed since then and so has the railway and the job it is required to do. And the average passenger wants a robust, reliable timetable that gets them where they want to go at the advertised time.

The new timetable will result in a lot of GWR services with typical end to end journey times close to what prevailed some years ago, but in most cases they will be making rather more stops along the way.

Guessing the trains are nearly in service with the final HST ever out of paddington on may 18th?

RealTrains07 said:

Guessing the trains are nearly in service with the final HST ever out of paddington on may 18th?

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All 800s are in service, and all of the 802s have been delivered

Dave1987 said:

Ow dear 5 car IET’s running on a bank holiday Friday absolutely rammed. Who thought it was a good idea to have 5 car sets again? Thought there was supposed to be loads more seats available with these things? I’m sure I was clearly told by certain people that there would be a considerable uplift in capacity when 5 car IET’s came in because they would always run around in pairs and only split where capacity wasn’t needed. Hmmmm that turned out to be complete rubbish....

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What you were told was that 5 car running wasn't going to be the default situation when you suggested that GWR would prefer to choose to run short services. The general situation is that the 80x's mostly run full length trains and it's only the fairly rare occasions when this isn't the case.

You were also told that once the new timetables started there would be an uplift in capacity. The fact that's been delayed would have an impact on GWR's ability to provide the number of seats over a day that they would like.

No one said that 5 coach units running wouldn't exist.

Is there evidence to show that significant services are running as 5 coaches opposed to a few services?