Why not more tilting stock?

Wapps

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Given 1) Avanti chose non-tilting stock for its new order, meaning slower trains than current, and 2) HS2 stock will not tilt, even though they will use the tilt enabled WCML, which also presumably means slower running, why have we moved away from tilt?

I know folks will say that the Class 80X has better acceleration than a Pendolino, but so it should given that it is a new train and the Pendo is about 20 years old. To me, true progress would have been to keep the existing tilt tech and combine it with improved acceleration to deliver something better than what we have now (rather than going backwards or at best standing still)*.

I believe Hitachi makes tilting trains. Could they not have brought that tech to the 80X series? Or Alstom or Siemens not have provided suitable replacements for the Super Voyagers?

* Does anyone know if the new Avanti 80X will be able to make, for example, Euston - Coventry, stopping once at MK, in the same time as a pendolino? It’s currently 58/9 mins. I struggle to see how the acceleration makes up for travelling slower for good stretches on this southern route.

Thank you.
 
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Jozhua

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Given 1) Avanti chose non-tilting stock for its new order, meaning slower trains than current, and 2) HS2 stock will not tilt, even though they will use the tilt enabled WCML, which also presumably means slower running, why have we moved away from tilt?

I know folks will say that the Class 80X has better acceleration than a Pendolino, but so it should given that it is a new train and the Pendo is about 20 years old. To me, true progress would have been to keep the existing tilt tech and combine it with improved acceleration to deliver something better than what we have now (rather than going backwards or at best standing still)*.

I believe Hitachi makes tilting trains. Could they not have brought that tech to the 80X series? Or Alstom or Siemens not have provided suitable replacements for the Super Voyagers?

* Does anyone know if the new Avanti 80X will be able to make, for example, Euston - Coventry, stopping once at MK, in the same time as a pendolino? It’s currently 58/9 mins. I struggle to see how the acceleration makes up for travelling slower for good stretches on this southern route.

Thank you.
My guess would be cost, loading gauge and existing supply chains. It is strange though, the tech certainly isn't exclusive to the UK. I doubt the WCML will be re-aligned as it is to be replaced by HS2 in the coming years and instead used by more regional/commuter services, where hitting a consistent 125mph will be less important, so any trains built for it now will pretty much be restricted to slowing for the bends as much as they are now.
 

Taunton

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Does anyone know if the new Avanti 80X will be able to make, for example, Euston - Coventry, stopping once at MK, in the same time as a pendolino? It’s currently 58/9 mins. I struggle to see how the acceleration makes up for travelling slower for good stretches on this southern route.
Should do; in 1967 (53 years ago), immediately after electrification, but before all sorts of further improvements on the route, and 100mph maximum limits, there were reports of then-new Class 86 making Euston to Coventry start to stop in under an hour - 59 minutes. The 100mph limit was treated a bit liberally, but not beyond 110mph.

Just 4 powered axles, vacuum brakes, etc. I quoted this a while ago and another of our regulars wrote they used to travel on the service and timed it so.
 

CW2

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There is a weight penalty for lugging around all the tilting equipment. Compare a class 220 (non-tilt) vehicle with an identical class 221 (tilt) vehicle and you'll find it works out at about 5 tonnes per vehicle. That means that tilt only makes sense if you are running on a particularly twisty route over a long distance. Otherwise the weight penalties (higher fuel consumption, slower acceleration, higher maintenance costs, more complexity) far outweigh the benefits.
 

cjmillsnun

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Given 1) Avanti chose non-tilting stock for its new order, meaning slower trains than current, and 2) HS2 stock will not tilt, even though they will use the tilt enabled WCML, which also presumably means slower running, why have we moved away from tilt?

I know folks will say that the Class 80X has better acceleration than a Pendolino, but so it should given that it is a new train and the Pendo is about 20 years old. To me, true progress would have been to keep the existing tilt tech and combine it with improved acceleration to deliver something better than what we have now (rather than going backwards or at best standing still)*.

I believe Hitachi makes tilting trains. Could they not have brought that tech to the 80X series? Or Alstom or Siemens not have provided suitable replacements for the Super Voyagers?

* Does anyone know if the new Avanti 80X will be able to make, for example, Euston - Coventry, stopping once at MK, in the same time as a pendolino? It’s currently 58/9 mins. I struggle to see how the acceleration makes up for travelling slower for good stretches on this southern route.

Thank you.
It shouldn’t be more than 2-3 minutes difference (and the stop at MK puts things in the new train’s favour).
 

James James

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Cost of developing it, cost of building it, cost of maintaining it, cost of carrying it around on every journey, cost of increased breakdowns due to additional complexity in the train - and in the UK, cost of lineside infrastructure apparently. There's a reason tilt usage is declining around the world.

Even more so when it comes to adding tilt to HS2 trains: probably possible, but in no way proportional to gains, when compared to the gain of going at high speed on the HS2 section of the journey.
 

OrangeJuice

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That surely absorbs one extra path on the Euston-Rugby line.
If they're pathed right, just before the 110mph LNR on the fasts then that shouldn't matter. It all depends if there's space created for the train to drop back into
 
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LNW-GW Joint

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Cost of developing it, cost of building it, cost of maintaining it, cost of carrying it around on every journey, cost of increased breakdowns due to additional complexity in the train - and in the UK, cost of lineside infrastructure apparently. There's a reason tilt usage is declining around the world.
Even more so when it comes to adding tilt to HS2 trains: probably possible, but in no way proportional to gains, when compared to the gain of going at high speed on the HS2 section of the journey.
Alstom's Avelia Liberty for Amtrak's NE corridor will have tilt capability, so it's not dead yet.
It can also run at HS2 speeds.
 

The Planner

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That surely absorbs one extra path on the Euston-Rugby line.
As mentioned on other threads, there is a lot of work going on to increase non-EPS speeds south of Weaver. They won't be running at 110mph all the way from Euston to Rugby, there are plans for a mixture of 115/120 and 125mph.
 

hexagon789

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Given 1) Avanti chose non-tilting stock for its new order, meaning slower trains than current, and 2) HS2 stock will not tilt, even though they will use the tilt enabled WCML, which also presumably means slower running, why have we moved away from tilt?

I know folks will say that the Class 80X has better acceleration than a Pendolino, but so it should given that it is a new train and the Pendo is about 20 years old. To me, true progress would have been to keep the existing tilt tech and combine it with improved acceleration to deliver something better than what we have now (rather than going backwards or at best standing still)*.

I believe Hitachi makes tilting trains. Could they not have brought that tech to the 80X series? Or Alstom or Siemens not have provided suitable replacements for the Super Voyagers?

* Does anyone know if the new Avanti 80X will be able to make, for example, Euston - Coventry, stopping once at MK, in the same time as a pendolino? It’s currently 58/9 mins. I struggle to see how the acceleration makes up for travelling slower for good stretches on this southern route.

Thank you.
It's more expensive to purchase tilting-trains particularly for the UK loading guage, they require higher maintenance, they are about 7-8 tonnes heavier per car and so incur higher track charges, they require expensive line side equipment to actuate the tilt.

Plus with Network Rail increasing non-tilt speeds to 125 on parts of the southern WCML (though mostly to 115-120mph) the difference in journey times will be negligible against the cost of maintaining tilt.

I forsee that when the Pendolinos are life expired they won't be replaced with tilting trains.

I suspect being able to run at 110mph with better acceleration means that the difference between a Pendo and an 80x will be fairy minimal.
They'll be running at up to 125 in places, but mostly at 115-120.
 

DorkingMain

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They'll be running at up to 125 in places, but mostly at 115-120.
Ahh, fair enough. I wasn't sure if it was one of those Network Rail "aspirations" or actually something that would reasonably occur lol

I agree on your point about tilting stock being old hat. It was a cheaper solution than sacrificing paths or re-engineering the network, at the time, but HS2, the ability to increase line speeds in sections and the ability to run regular trains at 110+ in fast paths has rather eradicated the need.
 

James James

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Alstom's Avelia Liberty for Amtrak's NE corridor will have tilt capability, so it's not dead yet.
It can also run at HS2 speeds.
Certainly, but those trains are expensive - and I was under the impression they benefit from tilting along a much larger portion of the route (vs when HS2 is done - at which point there's less track where tilting provides a benefit, as well as the other upgrades).

And it's rather notable that clearly the UK is in the process of dropping tilting, Germany has made the decision to drop it in future, France never really used it. In many cases high speed rail lines completely sidestep tilt train relevance. Tilt is a niche - highly useful in very specific circumstances (i.e. specific routes with sufficient journey time and length), but not broadly relevant, expensive, and HS2 makes it pretty much obsolete for the UK.
 

swaldman

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Suspect that tilt on the WCML may have made more sense when the expectation at the time - and the capability of the pendalinos - was max 140mph?
Presumably the track improvements that are allowing 115-120mph untilted on some sections would have allowed >125mph with tilt, if we hadn't subsequently decided that >125 requires in-cab signalling?
 

DavidB

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It's more expensive to purchase tilting-trains particularly for the UK loading guage, they require higher maintenance, they are about 7-8 tonnes heavier per car and so incur higher track charges, they require expensive line side equipment to actuate the tilt.

Plus with Network Rail increasing non-tilt speeds to 125 on parts of the southern WCML (though mostly to 115-120mph) the difference in journey times will be negligible against the cost of maintaining tilt.
And, with the relatively smallloading gauge we have, the tapered sides have a significant impact on the internal space - something very noticeable on both the Pendolinos and Voyagers.
 

Bald Rick

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Should do; in 1967 (53 years ago), immediately after electrification, but before all sorts of further improvements on the route, and 100mph maximum limits, there were reports of then-new Class 86 making Euston to Coventry start to stop in under an hour - 59 minutes. The 100mph limit was treated a bit liberally, but not beyond 110mph.

Just 4 powered axles, vacuum brakes, etc. I quoted this a while ago and another of our regulars wrote they used to travel on the service and timed it so.
This was planned, and not just a one off. The 2115 off Euston was timed non stop to Coventry in 59 mins in the late 90s. Max 100mph. The key thing, though, is it was non-stop.


If they're pathed right, just before the 110mph LNR on the fasts then that shouldn't matter. It all depends if there's space created for the train to drop back into
It’s not that simple.
 

Taunton

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If they're pathed right, just before the 110mph LNR on the fasts then that shouldn't matter. It all depends if there's space created for the train to drop back into
That means the whole timetable has to be written around handling what are now three different types of stock with incompatible performance. It may be fine when all works out; when things get disorganised (just when you need maximum throughput) that becomes an issue.

It's more of an issue in the Up direction. Writing about how Down trains all departing Euston are cleverly interlaced together in different performance bands is one thing, in the Up direction, where trains which left Scotland some hours earlier are expected to present and merge to the minute ahead of a conventional EMU from the Northampton line is more of a challenge. And obviously the throughput needs to be the same in either direction.

I suspect the next step will be slowing the Pendolino schedules down to the lowest common denominator. When it was the local service operator getting paths on the fast lines, nobody dared to suggest slowing the expresses down. Now it's the same TOC with different incompatible stock, the problem can be laid at their feet. You did it, you all run at the same speed.

This was planned, and not just a one off. The 2115 off Euston was timed non stop to Coventry in 59 mins in the late 90s. Max 100mph. The key thing, though, is it was non-stop.
Yes, that was the 1990s, after various improvements. But it was being reported by regular travellers in Modern Railways in 1967. Apparently certain drivers were recognised for it.
 
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Jozhua

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Alstom's Avelia Liberty for Amtrak's NE corridor will have tilt capability, so it's not dead yet.
It can also run at HS2 speeds.
I think the trains will be capable of up to HS2 speeds, the infrastructure definitely isn't. The current Acela units also have tilt, so I doubt they will have a higher service speed until infrastructure is upgraded.

I believe that the new Acela units will be lighter though as I think they are built to updated crash regs, so this will likely mean better acceleration.
Suspect that tilt on the WCML may have made more sense when the expectation at the time - and the capability of the pendalinos - was max 140mph?
Presumably the track improvements that are allowing 115-120mph untilted on some sections would have allowed >125mph with tilt, if we hadn't subsequently decided that >125 requires in-cab signalling?
Yeah, that makes a lot of sense. It seems like the classic network will probably always be limited to 125mph.
 

The Planner

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That means the whole timetable has to be written around handling what are now three different types of stock with incompatible performance. It may be fine when all works out; when things get disorganised (just when you need maximum throughput) that becomes an issue.

It's more of an issue in the Up direction. Writing about how Down trains all departing Euston are cleverly interlaced together in different performance bands is one thing, in the Up direction, where trains which left Scotland some hours earlier are expected to present and merge to the minute ahead of a conventional EMU from the Northampton line is more of a challenge. And obviously the throughput needs to be the same in either direction.

I suspect the next step will be slowing the Pendolino schedules down to the lowest common denominator. When it was the local service operator getting paths on the fast lines, nobody dared to suggest slowing the expresses down. Now it's the same TOC with different incompatible stock, the problem can be laid at their feet. You did it, you all run at the same speed.
No suggestion of that at all currently. Next big change will be Dec 2022 to incorporate the 800s and I very much doubt things will be slowed down.
 

Fisherman80

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Interesting thread. I wonder how much time would be added to the London to Glasgow schedule if the tilting mechanism was switched off on the Pendolinos and Class 221 Voyergers.
Also,would it not be possible to fit the above trains with more modern traction packages to make the acceleration on par with the 8xx classes of train?
I know everyone has a different opinion,but I find the ride quality on the 8xx classes of train absolutely appalling compared to a Pendolino.
 

Domh245

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Also,would it not be possible to fit the above trains with more modern traction packages to make the acceleration on par with the 8xx classes of train?
The 390s and 22x don't really have an issue with their traction packages, they're both relatively modern, so there's no major gains to be made from swapping it. A 9 car 80x has 4.5MW (cont.) of installed power, compared to a 9 car Pendolinos (~15m shorter) 5.1MW - the 'issue' is that the pendolino (and 22x) are both on the heavier side due to the tilt mechanism (although the 80x aren't exactly light either) - I personally remain unconvinced about the time savings an 80x will make on a pendolino under acceleration
 

Railperf

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The 390s and 22x don't really have an issue with their traction packages, they're both relatively modern, so there's no major gains to be made from swapping it. A 9 car 80x has 4.5MW (cont.) of installed power, compared to a 9 car Pendolinos (~15m shorter) 5.1MW - the 'issue' is that the pendolino (and 22x) are both on the heavier side due to the tilt mechanism (although the 80x aren't exactly light either) - I personally remain unconvinced about the time savings an 80x will make on a pendolino under acceleration
On a dry rail with full power applied, there is barely any difference in time saved accelerating from 0 to 125mph between a Pendolino and 80X. If anything the 80x seems slightly quicker at the lower end, whereas the Pendolino seems to have more power at the top end. The 11-Car Pendolino's have a slightly lower power to weight ratio than the 9-car sets. Similarly the 9-car 80X have a lower power to weight ratio than 2 x 5-car 80X.

A good driver and a good set in good conditions can make a bigger difference in running times.

Running 'on' line speed limits as opposed to 1-2mph below can also prove to be a factor. No stretch of line is immune to having the odd TSR in force either. If you were to run Pendolino's at non-tilt speeds - i'm pretty sure they would be assigned identical sectional running times to an 80X. Voyagers have slightly slower acceleration so i wouldn't be surprised if the additional half a minute added here and there to a Voyager schedule.

I've been on a late running Class 221 Voyager between Carlisle and Glasgow running with tilt disabled in 68 mins 46 seconds, The fastest Class 221 time in the Railway Performance Society archives is 65 mins 2 seconds - so 3 and 3/4 mins difference between our fastest recorded tilt and no tilt times on this section. The fastest Class 390 Pendolino time is less than 20 seconds quicker - pretty impressive as a Voyagers outright acceleration is not as good as a Class 80x.

In the grand scheme of things - pathing has to take into account freight trains and slower local srvices that use the WCML. Slower accelerating -100mph limited - Class 195 DMU's in use north of Preston towards Carnforth. There are 75mph Class 156's running to Glasgow for several miles along the WCML from Carlisle nortbound.

I noted in another thread that although Pendolinos are currenty assigned faster sectional running times from Preston northbound compared to Class 397, these time savings are being offset by longer dwell times - resulting in almost identical Preston to Carlisle running times. A passenger from Preston to Carlisle is being offered an identical journey time despite the Acanti service running at faster speeds. It does seem a waste!

Until capacity becomes an issue, I would hope Avanti will continue to run at the faster EPS speeds.

The whole tilt v not tilt argument seems to stem from a lack of coherent rolling stock policy. All TOC's running on the WCML fast lines should have been using tilt stock in order to maximise track capacity.

HS2 will provide time savings from London to Scotland, but what about Stockport or Crewe to Rugby or Milton Keynes - even Watford junction - I would be pretty peeved if my journey is going to get slower due to the lack of tilt.
And while we understand some non tilt WCML limits will be raised to nearer 115mph and 120mph, there are still a serious amount of severe curves that require tilt to run at higher than normal speeds.
Likewise, passengers from Scotland to greater Manchester shouldn't be having to suffer extended non-tilt journeys because the TOC's focus on faster journeys solely to Birmingham and London.
There is a strong argument to retain tilt in the long term. Indeed it is a shame that tilt was never adopted to speed up journeys along the ECML north of Darlington, and alongside a full MML electrification to improve journey times between London to Sheffield.
 

Ianno87

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The whole tilt v not tilt argument seems to stem from a lack of coherent rolling stock policy. All TOC's running on the WCML fast lines should have been using tilt stock in order to maximise track capacity.
Although south of Rugby it's irrelevant anyway. The non-EPS trains are largely fitted into the timetable in capacity that is 'wasted' for other reasons - e.g. the xx15 LNW path uses the path lost by the xx10 calling at Milton Keynes, etc.
 

hexagon789

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And, with the relatively smallloading gauge we have, the tapered sides have a significant impact on the internal space - something very noticeable on both the Pendolinos and Voyagers.
Indeed, you can make a much more spacious interior without the tilt as can be seen with the 221s vs 222s.

Ahh, fair enough. I wasn't sure if it was one of those Network Rail "aspirations" or actually something that would reasonably occur lol

I agree on your point about tilting stock being old hat. It was a cheaper solution than sacrificing paths or re-engineering the network, at the time, but HS2, the ability to increase line speeds in sections and the ability to run regular trains at 110+ in fast paths has rather eradicated the need.
It is actively being looked at, presently the intention is to have it signed off at the end of the year
 

Railperf

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There is a weight penalty for lugging around all the tilting equipment. Compare a class 220 (non-tilt) vehicle with an identical class 221 (tilt) vehicle and you'll find it works out at about 5 tonnes per vehicle. That means that tilt only makes sense if you are running on a particularly twisty route over a long distance. Otherwise the weight penalties (higher fuel consumption, slower acceleration, higher maintenance costs, more complexity) far outweigh the benefits.
Which is eaxctly what the WCML is - very long - over 400 miles London to Glasgow, 180-190 miles London to Manchester/Liverpool.
At the outset, we were looking at time savings of almost half an hour compared to the loco hauled services - which was not just down to tilt alone but modernising and upgrading many of the junctions, signalling and power supplies.
Until HS2 is alive and active as far as Crewe, tile is very much needed to keep journey times competitive on the WCML compared to driving and air travel.
And while the time savings on an HS2 train from anywhere north of Crewe to London will offset a slightly slower non tilt journey North of Crewe, people using 'classic' stations on the WCML will still want fast journeys to and from the intermediate stations that do not benefit from their services being able to use HS2.
There is nothing 'old hat' about tilt. It does a job, but cannot compare with genuine high-speed rail. The only reason other nations have abandoned tilt is where they have built a high-speed line to bypass or add additional capcacity to the classic one. In the case of HS2, it is only going as far as Crewe - eventually - so tilt is most definitley needed on the northern section. A variant 0f the US Avelia Liberty could be perfect rolling stock for the job - and it might be tried and tested too!
 

swaldman

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There is nothing 'old hat' about tilt. It does a job, but cannot compare with genuine high-speed rail. The only reason other nations have abandoned tilt is where they have built a high-speed line to bypass or add additional capcacity to the classic one. In the case of HS2, it is only going as far as Crewe - eventually - so tilt is most definitley needed on the northern section. A variant 0f the US Avelia Liberty could be perfect rolling stock for the job - and it might be tried and tested too!
Makes sense. Re other nations abandoning tilt: Japan hasn't.

They have tilting DMUs running express services on windy rural lines. It's less about the fastest, long distance, routes, and more about making better use of the old narrow-gauge infrastructure.
Having said that, I think some of the newer shinkansen trains also tilt a little, presumably to get better use out of the slightly older parts of that network which had smaller minimum bend radii.
 

stj

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I thought the original concept of APT was 155mph top speed and higher speeds than we have now on curves.How much time is really being saved using tilt and 125 max v non tilt and 125 max?
 
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Makes sense. Re other nations abandoning tilt: Japan hasn't.

They have tilting DMUs running express services on windy rural lines. It's less about the fastest, long distance, routes, and more about making better use of the old narrow-gauge infrastructure.
Having said that, I think some of the newer shinkansen trains also tilt a little, presumably to get better use out of the slightly older parts of that network which had smaller minimum bend radii.
Yes, JR Hokkaido does have tilting DMUs. JR Central/West and East use tilting EMUs (including one Hitachi A-train) on some limited express services around Osaka and Tokyo. Taiwan has also imported Hitachi A-train sets for use on tilting services. And you are correct, the new N700 series shinkansen sets can tilt on sections of the Tokkaido shinkansen in order to get top speeds more in line with the 320kph possible on the Tohoku shinkansen. Japan is a very different case than the UK however - rail travel is the principle mode of travel and they have an extremely conservative (and possibly restrictive) policy with regards to railway operation - ie. trains don't conflict paths with one another, very clear and strict regulation policies, services waiting for connections etc. and single operator to each line. The latter point makes building timetables a lot more simple as there are not competing companies.

With regards to cl. 390s vs. cl 80xs, I won't rehash the speed point as it seems to have been done to death already. But with regards to reliability, yes the 80xs are going to be more reliable with no tilting equipment but we're not comparing like for like. The class 390 is a nearly 20 year old design (possibly older as based on an earlier pendolino from Alsthom) whilst the 800s are based on significantly more recent designs. Ultimately it will depend on the condition in which the 800s are kept which will govern whether there will be an uplift in the performance when compared to the pendolinos. This being said, the current reliability of the 800s are about on par with the 20 year old pendolinos - and yes I am aware that fleet introductions are often fraught with difficulty. Time will tell.
 

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