Class 810 - The Right Fit For EMR?

Teapot42 · 14 Jul 2026

ExRes said:
Fair enough, but what point is there extending something which would no longer be fit for the purpose it was built?

There is only a problem with the platforms if the trains can be extended. If it was the case they could, then I'd start another thread under speculation for ways that could be resolved.

== Doublepost prevention - post automatically merged: 14 Jul 2026 ==

DaveyJones said:
Sadly this Article is behind a paywall, but if its the presentation I think it is, it's a really interesting article about how they managed the Phasing of the additional Transformer

https://digital-library.theiet.org/doi/10.1049/ic.2012.0086

Thanks, I'll see if I can find a copy somehow. Unfortunately I don't know the right person to give a handshake to be able to join the IET, but I'm sure there are copies available elsewhere. I'd imagine maintaining a reasonable power factor isn't trivial even with a single transformer, so adding extra ones will make it even more complicated to manage.

RailUK Forums

dosxuk · 14 Jul 2026

It's a chicken and egg thing. There's no point extending the trains if the platforms can't be extended. And there's no point extending the platforms if the trains can't be lengthened. Both are almost certainly possible, but the works would be by no means simple - and whether it's actually worth it would be the main question. You can't really separate the questions like you're asking - they are intrinsically linked.

Bletchleyite · 14 Jul 2026

dosxuk said:
It's a chicken and egg thing. There's no point extending the trains if the platforms can't be extended. And there's no point extending the platforms if the trains can't be lengthened. Both are almost certainly possible, but the works would be by no means simple - and whether it's actually worth it would be the main question. You can't really separate the questions like you're asking - they are intrinsically linked.

This isn't so. Potentially a mixed fleet of 5 and 7 car units, as they had with the 222s, would allow a closer match of capacity to demand than only having the options of 5 and 10.

hwl · 14 Jul 2026

Bletchleyite said:
Pendolinos have multiple transformer cars to deal with this. I think a 9 car has 2 and an 11 car has 3?

The pantograph could presumably be replaced with one with higher capacity, with a high voltage bus line added along the roof to the other transformer cars.

As covered in post 2 above the pantograph capacity is not the issue, only currently at ~1/3 of capacity

== Doublepost prevention - post automatically merged: 14 Jul 2026 ==

Teapot42 said:
I'd imagine maintaining a reasonable power factor isn't trivial even with a single transformer, so adding extra ones will make it even more complicated to manage.

Modern traction electronics have a 4QC which gives you the ability to manage power factors in either transformer load or regen modes.

sharpener · 14 Jul 2026

Teapot42 said:
There is only a problem with the platforms if the trains can be extended. If it was the case they could, then I'd start another thread under speculation for ways that could be resolved.

== Doublepost prevention - post automatically merged: 14 Jul 2026 ==

Thanks, I'll see if I can find a copy somehow. Unfortunately I don't know the right person to give a handshake to be able to join the IET, but I'm sure there are copies available elsewhere. I'd imagine maintaining a reasonable power factor isn't trivial even with a single transformer, so adding extra ones will make it even more complicated to manage.

DaveyJones said:
Sadly this Article is behind a paywall, but if its the presentation I think it is, it's a really interesting article about how they managed the Phasing of the additional Transformer

https://digital-library.theiet.org/doi/10.1049/ic.2012.0086

Not sure what you mean by "phasing" in the context. The article makes clear the 4-quadrant converters manage the power draw to have a PF of 1 or nearly so as well as permitting regenerative braking.

I was surprised the lengthened trains take 7.8 MW (312A) through a single pantograph. They don't seem to want to do that with the 700s.

Here for the purposes of private study is a more detailed extract:

3.1 Additional Traction Equipment
The two new vehicles comprise a transformer car (without
pantograph) and a motor-car. The feed for the transformer is
taken from the 25kV roof busline.

Wherever practical the equipment installed on the Additional
Cars is identical to the original design. This minimised the
amount of validation testing and safety assurance activities
required at component level and brings the added benefit that
the train operators and maintenance staff are already familiar
with the equipment. One particular example of note is the
Main Transformer installed on the new vehicle. This is
identical to the transformers fitted on the existing pantograph
cars even though only 2 of the 5 windings are utilised.
The strategy of replicating a 10-year old design presented
many challenges, with a number of original suppliers having
ceased training and obsolescence affecting many parts,
particularly electronic components. There were many design
improvements that had been implemented on the trains that
needed to be introduced by the suppliers for the new build
and changes to industrialisation strategies meant that a
number of major items were now manufactured at new sites.
This return of experience and technology transfer became a
crucial factor to the success of the project.

Trainman40083 · 14 Jul 2026

I was going to ask if a Hull Trains unit and a EMR Class 810 would fit in one platform at St Pancras. I suspect not, given the longer length of the HT unit. But if so it takes out a platform when it is there

tbtc · 14 Jul 2026

The main benefit of lengthening would be if we accept that some diagrams will effectively be double sets all day long, and decide that having one train that length would be better

However, from what I've seen of 800/801/802/807/809, I understand that those Hitachi units can only run in odd numbered carriage lengths

If that's the case for 810s too (?) then ten coaches wouldn't be possible, so IMHO there seems little point in complicating things by creating a few seven/nine coach units (too short to fill St P's platforms, too long to be doubled up, no specific diagrams needing them (compared to other main lines which might have services suited to a seven coach train - Kings Cross to Lincoln, Euston to Chester)

Better to keep things simple, buy some more five coach sets by all means, but a seven coach unit would be neither nowt nor summat, as we say at this end of t'MML

Bletchleyite · 14 Jul 2026

A ten car unit would clearly be possible by building two fives but with a gangwayed slab end. I believe Greater Anglia's FLIRTs are of this nature, basically being two permanently coupled units, because a 12 car length is not on offer.

== Doublepost prevention - post automatically merged: 14 Jul 2026 ==

tbtc said:
a seven coach unit would be neither nowt nor summat, as we say at this end of t'MML

It seems a fairly useful length over here on the WCML, at least on quieter services like the slower Liverpool and the Birmingham semifast.

pokemonsuper9 · 14 Jul 2026

Bletchleyite said:
A ten car unit would clearly be possible by building two fives but with a gangwayed slab end.

Surely there'd be little reason to get a bespoke 10*24m (240m) built instead of just getting a standard 9*26m (234m) which already exist as various 800/801/802 fleets.
The only reason the smaller 810 carriages were such is because St Pancras couldn't fit 2 5*26m trains in the platform, having 9 cars removes this problem.

Bletchleyite · 14 Jul 2026

pokemonsuper9 said:
Surely there'd be little reason to get a bespoke 10*24m (240m) built instead of just getting a standard 9*26m (234m) which already exist as various 800/801/802 fleets.
The only reason the smaller 810 carriages were such is because St Pancras couldn't fit 2 5*26m trains in the platform, having 9 cars removes this problem.

To be honest my view was that they should indeed have ordered 9x26 and 7x26 units and not 5s. But what's done is done.

hwl · 14 Jul 2026

sharpener said:
Not sure what you mean by "phasing" in the context. The article makes clear the 4-quadrant converters manage the power draw to have a PF of 1 or nearly so as well as permitting regenerative braking.

I was surprised the lengthened trains take 7.8 MW (312A) through a single pantograph. They don't seem to want to do that with the 700s.

Here for the purposes of private study is a more detailed extract:

3.1 Additional Traction Equipment
The two new vehicles comprise a transformer car (without
pantograph) and a motor-car. The feed for the transformer is
taken from the 25kV roof busline.
View attachment 207638

Wherever practical the equipment installed on the Additional
Cars is identical to the original design. This minimised the
amount of validation testing and safety assurance activities
required at component level and brings the added benefit that
the train operators and maintenance staff are already familiar
with the equipment. One particular example of note is the
Main Transformer installed on the new vehicle. This is
identical to the transformers fitted on the existing pantograph
cars even though only 2 of the 5 windings are utilised.
The strategy of replicating a 10-year old design presented
many challenges, with a number of original suppliers having
ceased training and obsolescence affecting many parts,
particularly electronic components. There were many design
improvements that had been implemented on the trains that
needed to be introduced by the suppliers for the new build
and changes to industrialisation strategies meant that a
number of major items were now manufactured at new sites.
This return of experience and technology transfer became a
crucial factor to the success of the project.

The theoretical max for a pan is meant to be 300A. (7.5MW at 25kV)

With Thameslink they didn't have to worry about the impact of oscillations in the contract wire with multiple pantographs above the then threshold of 100mph (revised upwards in the last 15 years with lots of R&D for 350s, 360, 387s and 80x). When the 390s were being designed they had to go for 1 pantograph operation due to the max operating speed and rules at the time resulting in lots of 25kV bus wire but not for the 700s (which are effectively two half units of 4/6 cars).

43074 · 14 Jul 2026

A constraint which hasn't been mentioned is that the maintenance shed at Etches Park is sized for a 7-car 222, so any formation exceeding a theoretical 7-car would either need to be split or overhang the depot roads during maintenance (short of building a new depot).

A theoretical 7-car 810 would have around 460 seats which is 20 seats fewer than a 10-car 222, but virtually mid-range between 301 seats on a 5-car 810 and 602 on a 10-car 810.

Noting the MML worked reasonably well with a mix of 4, 5 and 7-car 222s prior to 2022 there's no reason mixed formations wouldn't work with 810s. As pointed out Avanti manage to optimise formations between 5- and 7-car 80x, no reason EMR couldn't.

Bletchleyite · 14 Jul 2026

43074 said:
A constraint which hasn't been mentioned is that the maintenance shed at Etches Park is sized for a 7-car 222, so any formation exceeding a theoretical 7-car would either need to be split or overhang the depot roads during maintenance (short of building a new depot).

What did they used to do when they were 4s, 5s and 9s? Or is the depot new?

43074 · 14 Jul 2026

Bletchleyite said:
What did they used to do when they were 4s, 5s and 9s? Or is the depot new?

The current maintenance building opened around 2012 if I remember rightly, before that the 9-cars were split but the 4/5 car sets could be accommodated in what is now the Regional depot.

Starmill · 14 Jul 2026

Bletchleyite said:
A ten car unit would clearly be possible by building two fives but with a gangwayed slab end. I believe Greater Anglia's FLIRTs are of this nature, basically being two permanently coupled units, because a 12 car length is not on offer.

There are quite a few units with similarish structure now. 700s and 701s also function a little like that.

== Doublepost prevention - post automatically merged: 14 Jul 2026 ==

Bletchleyite said:
What did they used to do when they were 4s, 5s and 9s? Or is the depot new?

I seem to recall that part of the reason they had few 9 car sets, or indeed no 9 car sets, for a time was because they would overhang like this, making it more tricky to reach everything.

sharpener · 14 Jul 2026

hwl said:
The theoretical max for a pan is meant to be 300A. (7.5MW at 25kV)

I got the 7.8 figure from the conference paper upthread. This Wikipedia article has 6.02 MW for the 390/1, which is fractionally over 240A, it may well be that different limits apply in service anyway.

Spartacus · 15 Jul 2026

Bletchleyite said:
To be honest my view was that they should indeed have ordered 9x26 and 7x26 units and not 5s. But what's done is done.

Do that and you've got to accept a lower frequency service as they're unable to double up at St Pancras. Lower frequency would mean less trains required anyway.

hwl · 15 Jul 2026

sharpener said:
I got the 7.8 figure from the conference paper upthread. This Wikipedia article has 6.02 MW for the 390/1, which is fractionally over 240A, it may well be that different limits apply in service anyway.

The value set in the software are lower than the hardware maximums. If I remember there is an entire discussion thread on 390 traction software settings.

Bletchleyite · 15 Jul 2026

Spartacus said:
Do that and you've got to accept a lower frequency service as they're unable to double up at St Pancras. Lower frequency would mean less trains required anyway.

There appear to be 6tph EMR from St Pancras - 2 Corby, 2 Nottingham, 2 Sheffield. Can they really not do that with 4 platforms without doubling up? If you give the EMUs a shortish turnaround and dedicate one to them (as they have at Euston on very similar services) that means the other platforms would mean 5 trains occupying 4 platforms in an hour - is that really that hard to schedule?

biggerisbetter · 15 Jul 2026

tbtc said:
The main benefit of lengthening would be if we accept that some diagrams will effectively be double sets all day long, and decide that having one train that length would be better

However, from what I've seen of 800/801/802/807/809, I understand that those Hitachi units can only run in odd numbered carriage lengths

If that's the case for 810s too (?) then ten coaches wouldn't be possible, so IMHO there seems little point in complicating things by creating a few seven/nine coach units (too short to fill St P's platforms, too long to be doubled up, no specific diagrams needing them (compared to other main lines which might have services suited to a seven coach train - Kings Cross to Lincoln, Euston to Chester)

Better to keep things simple, buy some more five coach sets by all means, but a seven coach unit would be neither nowt nor summat, as we say at this end of t'MML

Presuming that the ship has sailed on this now but is anyone aware if:

- Are there many platforms served by the units where 10 x 24m units would not fit or where SDO is not feasible?
- Would it be feasible to extend the current units to 10-car (in a fixed 5+5 formation) without wasting any carriages?
- How much over capacity would be provided if all units were extended to 10-car? - presumably some of this could be offset by extending some Sheffield services north to provide London services to Barnsley or Rotherham (albeit substantial over capacity on these short sections) and use of units for seasonal Skegness and Grand National services.

Spartacus · 15 Jul 2026

Bletchleyite said:
There appear to be 6tph EMR from St Pancras - 2 Corby, 2 Nottingham, 2 Sheffield. Can they really not do that with 4 platforms without doubling up? If you give the EMUs a shortish turnaround and dedicate one to them (as they have at Euston on very similar services) that means the other platforms would mean 5 trains occupying 4 platforms in an hour - is that really that hard to schedule?

Platform 1's not pretty much dedicated to the Corby services, and I suspect if you cut down on their turnarounds you'd be cutting into breaks, though in theory you could go as low as 8 on those. It might work in isolation, but a big thing is if you cut them down where do you fit them into the Thameslink timetables, and some of those trains HAVE to be doubled up because they attach and split en route

AndrewJM70 · 15 Jul 2026

I am not sure why they didn't order longer trains to start with. It seems like the tail wagging the dog as usual. A mix of 7 and 9 car trains would have only required around 26 sets, would have eliminated the staffing complexity of 2 x 5 car and the trains would not have all the issues these botch jobs have now.

Trainman40083 · 15 Jul 2026

AndrewJM70 said:
I am not sure why they didn't order longer trains to start with. It seems like the tail wagging the dog as usual. A mix of 7 and 9 car trains would have only required around 26 sets, would have eliminated the staffing complexity of 2 x 5 car and the trains would not have all the issues these botch jobs have now.

I guess if they had had access to more than 3 platforms at St Pancras (much of the time) it could have been different. But we will see two 5 cars in one platform for different services (a Sheffield and a Nottingham)...But even before Auroras there were 10 car trains, that would split en route, and park up at the likes of Cricklewood to await the evening Peak. Or they would return North and split allowing one set to go back to Etches Park for exam. You would certainly lose the flexibility.

Teapot42 · 15 Jul 2026

I believe there are some stations that can't even accommodate a 5 car train? Long Eaton maybe? That said, it is essential the smaller places have a direct or as fast a service to London if there is a benefit to the wider network?

Something like the existing Aurora could, for example, be used to extend the Corby service to Derby and Nottingham once an hour each to serve the smaller stations and add Oakham and Melton Mowbray on to the map for direct London connections.

ExRes · 15 Jul 2026

Teapot42 said:
I believe there are some stations that can't even accommodate a 5 car train? Long Eaton maybe? That said, it is essential the smaller places have a direct or as fast a service to London if there is a benefit to the wider network?

Something like the existing Aurora could, for example, be used to extend the Corby service to Derby and Nottingham once an hour each to serve the smaller stations and add Oakham and Melton Mowbray on to the map for direct London connections.

I would hope that the Aurora has proper selective door opening, with a Meridian you could stop on a one car platform with a nine car unit and select one door to open, if after all these years the Aurora can't do the same then it's an utter disgrace

Spartacus · 15 Jul 2026

ExRes said:
I would hope that the Aurora has proper selective door opening, with a Meridian you could stop on a one car platform with a nine car unit and select one door to open, if after all these years the Aurora can't do the same then it's an utter disgrace

How've we got to "utter disgrace"? 810s have SDO.

InTheEastMids · 15 Jul 2026

biggerisbetter said:
Presuming that the ship has sailed on this now but is anyone aware if:

- Are there many platforms served by the units where 10 x 24m units would not fit or where SDO is not feasible?
- Would it be feasible to extend the current units to 10-car (in a fixed 5+5 formation) without wasting any carriages?
- How much over capacity would be provided if all units were extended to 10-car? - presumably some of this could be offset by extending some Sheffield services north to provide London services to Barnsley or Rotherham (albeit substantial over capacity on these short sections) and use of units for seasonal Skegness and Grand National services.

Reengineering them as single ended 5-cars (semi) permanently coupled back to back. might get you 32-40 seats compared to existing 2x5 car. But EMR would need about 23 10-car trains to cover 19 diagrams and so this idea only needs 46 driving vehicles. 66 are already built and would be redundant or need £££ conversions to be decabbified.

I don't for a moment think it'll happen but it seems so much more cost effective and lower risk to just do a follow on order and keep the versatility of a 5 car fleet.

The fact that HS2 was supposed to turn up in the East Midlands midway through the 810 life and now won't, means capacity may be more of an issue than was firm when the trains were ordered. But that's a Tomorrow Problem

I think most people would rather EMR/GBR/Hitachi did a better job of tackling the Today Problems, which are set out over about 94 thousand pages of woe on the 810 intro and 222 reliability threads

Teapot42 · 15 Jul 2026

InTheEastMids said:
The fact that HS2 was supposed to turn up in the East Midlands midway through the 810 life and now won't, means capacity may be more of an issue than was firm when the trains were ordered. But that's a Tomorrow Problem

This is actually a point I've not seen mentioned previously. Part of the reason I asked this question is that even on quiet services the trains seem busy. At weekends and after the peak restrictions are lifted they seem regularly rammed. If things like net zero are being taken even remotely seriously then getting more people on to longer distance trains is bound to be an aim of GBR, so to not really have capacity to do that seems a major issue.

ExRes · 15 Jul 2026

Spartacus said:
How've we got to "utter disgrace"? 810s have SDO.

I have no idea whatsover the types of SDO that are fitted to modern units, I've seen various posts on the forum about units not being able to stop on short platforms because of SDO limitations, as someone who drove Meridians from brand new I find it unbelievable that there are any modern units that aren't equally fitted, comments I've seen have suggested that 810s didn't have it and if that was correct then I would most certainly consider it an utter disgrace, I'm most relieved to hear they have

Trainbike46 · 15 Jul 2026

Trainman40083 said:
I guess if they had had access to more than 3 platforms at St Pancras (much of the time) it could have been different. But we will see two 5 cars in one platform for different services (a Sheffield and a Nottingham)...But even before Auroras there were 10 car trains, that would split en route, and park up at the likes of Cricklewood to await the evening Peak. Or they would return North and split allowing one set to go back to Etches Park for exam. You would certainly lose the flexibility.

In a different thread, I showed how it would be possible to run the current timetable without having services share platforms, though it does require changing the diagrams. Currently platform sharing happens because it is possible and easier, but it is not essential, especially if all services are the same length (e.g., a full 9-car fleet).

However, I do think it is important to note that the 810s are a significant capacity upgrade for EMR.

Class 810 - The Right Fit For EMR?

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