Class 701 'Aventra' trains for South Western Railway: progress updates

[swr444]

Is there any more clarity yet on whether the 458/4s or the 450s will be the next units to be displaced by the 701s?

The main line could certainly do with some strengthening of 450 (and, by cascade, 444) services.

450s will most certainly be next, as they can be used elsewhere, like you said.

 

[WWTownEnth]

450s will most certainly be next, as they can be used elsewhere, like you said.

Thanks. I had vague memories of reading elsewhere that the 458/4s would go first as they are proving so unsuitable on inner suburban / Windsor side services. But what you say seems more logical.

 

[NSEWonderer]

Thanks. I had vague memories of reading elsewhere that the 458/4s would go first as they are proving so unsuitable on inner suburban / Windsor side services. But what you say seems more logical.

Not any more than 450s which struggle to keep to time on almost all windsor side services, minus a Reading run.

 

[43096]

Not any more than 450s which struggle to keep to time on almost all windsor side services, minus a Reading run.

450s have always struggled to meet running times on Reading runs, too; albeit a bit less of an issue now with all the padding added into the timetable.

 

[mansonlo49]

I think it possible that SIMS at Newport might be more overstretched than WPS (Wimbledon Park Sidings) !.

Last week there were three movements of 701s
12/11/2025 701010 to Wimbledon from Long Marston
13/11/2025 701016 to Eastleigh from Marchwood
14/11/2025 701019 to Wimbledon from Marchwood

So I am wondering if Long Marston is sending a 701 to Eastleigh this week ?.
I feel unlikely and that Marchwood is getting cleared out, particularly of more ready 701s.

EDIT 22:32
They are both 5Q84.
There is no light loco in the system (yet) for the loco to return from Wimbledon to Eastleigh / Marchwood after the 19/11 delivery so I wonder if that is a rogue entry.

the 5Q84 seems cancelled today (20/11) and still there’s no sign of Long Marston drags

 

[DMckduck]

SWR could do well with those extra 10 roads at Feltham that they have planning for right now.

 

[Dstock7080]

SWR could do well with those extra 10 roads at Feltham that they have planning for right now.

In relation to the existing sidings, where will these be?

 

[Olivine]

In relation to the existing sidings, where will these be?

It would be a bit tight but you could probably just fit another 9 on the south side and 1 on the north side. Juggling the space around though.

 

[WWTownEnth]

Would they all be able to store 10 car units?

 

[NSEWonderer]

Would they all be able to store 10 car units?

Yep. Feltham was created mainly for the 701 purpose.

 

[DMckduck]

In relation to the existing sidings, where will these be?

They will go next to the current roads on the woodland side of the depot.

 

[swt_passenger]

They will go next to the current roads on the woodland side of the depot.

Wasn’t there an attempt to declare that as some sort of protected wildlife habitat, (although it was NR unused and unloved operational land), back when the current sidings were in development?

 

[deepeetw]

Is there actually planning in for a further 10? I can only see the original application to bring the yard back into use on the Hounslow Planning Portal.

 

[w11_supremecy]

Not any more than 450s which struggle to keep to time on almost all windsor side services, minus a Reading run.

Agreed. As much as the 458/4s aren't great, the Desiros are not built for suburban services at all whatsoever. They struggle to keep to time nearly all the time since the door opening/closing takes what seems like forever. The 458s are quicker in this regard despite the issues those trains have.

 

[swr444]

Agreed. As much as the 458/4s aren't great, the Desiros are not built for suburban services at all whatsoever. They struggle to keep to time nearly all the time since the door opening/closing takes what seems like forever. The 458s are quicker in this regard despite the issues those trains have.

If you have a confident driver who knows how to use the desiro braking properly then you can keep to time. A lot of drivers are overly cautious with the desiro brakes as they have a slight delay in them

 

[Goldfish62]

If you have a confident driver who knows how to use the desiro braking properly then you can keep to time. A lot of drivers are overly cautious with the desiro brakes as they have a slight delay in them

And in my experience as a passenger a guard who's quick on the doors.

 

[swr444]

And in my experience as a passenger a guard who's quick on the doors.

Definitely, I've kept many weybridge via hounslow services on time with a 450. Just need a good team and you can easily have dwells at each station

 

[mansonlo49]

Is this 701 to old Dalby? Thanks

Realtime Trains | 5Q70 1050 Derby Litchurch Lane to Old Dalby | 20/11/2025

Real-time train running information for 5Q70 1050 departure from Derby Litchurch Lane to Old Dalby on 20/11/2025. From Realtime Trains, an independent source of train running info for Great Britain.

www.realtimetrains.co.uk

 

[43096]

Definitely, I've kept many weybridge via hounslow services on time with a 450. Just need a good team and you can easily have dwells at each station

Agreed. But unfortunately that is very much the exception rather than the rule.

 

[w11_supremecy]

If you have a confident driver who knows how to use the desiro braking properly then you can keep to time. A lot of drivers are overly cautious with the desiro brakes as they have a slight delay in them

Oh definitely it is possible, I’ve had many a discussion about this, it’s just in my experience it’s rare for me to have a driver who has that level of control/confidence. Many a time the train loses time no matter how sharp I am in doing the doors because of the caution arriving into stations. But I do get it though, I have had conversations about this and ultimately they are trying to not be caught out by the lag. Although I still think the Desiros are not built for metro services, and the door cycle is way too slow IMO.

 

[BigB]

Is this 701 to old Dalby? Thanks

Realtime Trains | 5Q70 1050 Derby Litchurch Lane to Old Dalby | 20/11/2025

Real-time train running information for 5Q70 1050 departure from Derby Litchurch Lane to Old Dalby on 20/11/2025. From Realtime Trains, an independent source of train running info for Great Britain.

www.realtimetrains.co.uk

This was reported on Railcam as being possibly 387101...

 

[Big Jumby 74]

Definitely, I've kept many weybridge via hounslow services on time with a 450. Just need a good team and you can easily have dwells at each station

For what it's worth, for performance/timetable reasons I undertook a half day of rides between Aldershot and Guildford many years ago in the course of my duty, as with a 5 min turn round at GF, planning had received complaints about late arrivals at GF, resulting in (on occasion) late starts on the return. This was during the period that the Guildford-Ascot route was worked (SX) by 2 x 458/0 and 3 x 450 IIRC.

The result was that those drivers I interacted with found the braking on 458's (this is 458's in original as built 458/0 mode) to be more responsive, and gave more confidence when approaching stations, and the door operation may also have had some input as well.

Suffice to say overall, it wasn't that much of a problem to require a timetable re write, not that this would have been achievable due to the mix of pathways, junction margins etc on the overall GF-Ascot route.

 

[mansonlo49]

This was reported on Railcam as being possibly 387101...

Thanks I see，just thought it could be 701, as it’s GBRF and to old dalby

 

[NSEWonderer]

If you have a confident driver who knows how to use the desiro braking properly then you can keep to time. A lot of drivers are overly cautious with the desiro brakes as they have a slight delay in them

Not so much a confident Desiro driver, the doors take time regardless and a slightly cautious guard, wheelchair or less than optimal signaling and you're losing time. Doesn't help the 450s are still capped at 50-60% max traction above 15mph either. Readings you can get away with it most of the time, Weybridges and Windsor there is barely any chance if those are busy / peak time trains with 450s. Unlike the 701s, 455s and 458s, you have enough advantages in those trains to actually make up lost time which is arguably what the 450s can't do, they're just about as you say able to keep to time in optimal circumstances.

 

[WWTownEnth]

well let‘s hope SWR do the logical thing and start moving all 450s back to thr main line in January.
how many 450 diagrams are currently working inner suburban and Windsor side services?

 

[hwl]

well let‘s hope SWR do the logical thing and start moving all 450s back to thr main line in January.

Yes hope is exactly the right word to go with SWR and doing right/sensible/logical right thing...

The reality is that they will need to maintain some level of driver competency on 450s for mainline diversions and an obvious way to do that is some of the Chertsey etc. services but would that be enough.

I suspect there will be a slight breather on 701 roll out after the last 455 is retired to allow a bit of a reset at maintenance facilities which will be better for further roll out in the medium term.

 

[WWTownEnth]

Yes hope is exactly the right word to go with SWR and doing right/sensible/logical right thing...

The reality is that they will need to maintain some level of driver competency on 450s for mainline diversions and an obvious way to do that is some of the Chertsey etc. services but would that be enough.

I suspect there will be a slight breather on 701 roll out after the last 455 is retired to allow a bit of a reset at maintenance facilities which will be better for further roll out in the medium term.

Thanks. When you say “breather” do you mean simply in terms of changes to diagrams? Presumably the conveyor belt of pulling units out of storage and preparing them for passenger service will continue uninterrupted? there are currently 16 floating around SWR and not in passenger service right now and I would assume they would want those out in traffic asap?

 

[hwl]

Thanks. When you say “breather” do you mean simply in terms of changes to diagrams? Presumably the conveyor belt of pulling units out of storage and preparing them for passenger service will continue uninterrupted? there are currently 16 floating around SWR and not in passenger service right now and I would assume they would want those out in traffic asap?

Probably both to an extent. Making sure everything is configured just for 701s and 458s at depots (e.g. clearing out 455 spares, some roads in Wimbledon may still be configured around 455s so swapping those over) will make it easier to maintain greater numbers of 701s and help with the pace of getting new units into service. There may also be some reshuffling with no net new 701 diagrams once the last 455 has gone.

 

[43096]

I suspect there will be a slight breather on 701 roll out after the last 455 is retired to allow a bit of a reset at maintenance facilities which will be better for further roll out in the medium term.

They need to get the number of 701s available up to a sustainable level for the number of diagrams. The current almost 100% availability requirement for the 701s is unsustainable.

 

[Siemens Staines]

well let‘s hope SWR do the logical thing and start moving all 450s back to thr main line in January.
how many 450 diagrams are currently working inner suburban and Windsor side services?

This week there are 10 pairs of 450 on inner suburban diagrams and four pairs of 450 on outer suburban Windsor line diagrams. One of the latter is peak hours only.