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

[TT-ONR-NRN]

Read it again, lower numbers is slower, therefore the 701 is a downgrade from the 707 and the 444/450

There’s no way a 701 or 707 has poorer acceleration than a 450.

 

[gabrielhj07]

Do keep in mind that according to the stats, the 701 is the slowest accelerating aventra (0.7), and the 707s which were in service a while ago did 0.85. The 450s and 444s do 1.0 for reference.

How does it compare to the 455?

 

[Goldfish62]

There’s no way a 701 or 707 has poorer acceleration than a 450.

Absolutely no way. These are high performance units.

 

[PGAT]

How does it compare to the 455?

I think the 455 is 0.58

 

[Goldfish62]

Read it again, lower numbers is slower, therefore the 701 is a downgrade from the 707 and the 444/450

Absolutely no way. These are high performance units. That was abundantly evident the way the thing took off like a scalded cat when I saw it at Richmond this afternoon.

This article quotes Class 720 acceleration as 0.8:

New Trains in a Pandemic - Rail Engineer

Listen to this article Introducing Greater Anglia’s new Aventra trains into service In August 2016 Abellio was awarded a long-term franchise to run the Greater Anglia network from October 2016 for nine years to 2025. The big surprise was the commitment to replace the entire fleet of trains...

www.railengineer.co.uk

That makes perfect sense in the context of the 701 being 0.7.

The only explanation is that the performance quoted for 707, 444 and 450 are evidently way overstated. It's patently absurd to suggest that a 444 has better acceleration than a 720.

 

[Big Jumby 74]

Just thinking aloud as one does from time to time, but power supply was an issue even in SWT days, certain parts of the main line area were restricted in relation to the numbers of trains drawing power within a given area, as I (perhaps mistakenly?) understand it. Since then there have been I believe a number of upgrades in that department, substations etc, and most third rail feeds have been doubled to give better resilience. This will have been investigated during the bid process for the 701 fleet, I am sure, given that overall, there will be a far larger fleet of trains in the inner area with modern on-board tec than has hitherto been the case. Wondering if subsequent testing may have thrown up any problems that are still being worked through?

 

[Nicholas Lewis]

There’s no way a 701 or 707 has poorer acceleration than a 450.

The 450's were throttled at birth with software restrictions on power demand due to the disjointed industry not working out that more powerful trains would need more juice. This means they currently have a power envelope similar to the EP stock they replaced but are heavier and also have the additional hotel load to power. However, they have more than adequate traction power installed to compete with 701/707's but software would need remapping and no doubt that would need a new safety case as well as a higher electricity bill. By the time 707 and 701's were ordered much of the infrastructure had been upgrade to high current railway standard so they weren't constrained (as much).

 

[Snow1964]

Not bitter or angry, just resigned and a wee bit of schadenfreude that First's Big Idea that won them them franchise proved to be built on sand. (Not that I was any fan of Stagecoach).
But then, I retired in 2019, so the fact that I did not just miss out on the new trains but would have had to stay working until 2024 to "feel the benefit" is less of a disappointment. (My first commuting was on EPBs - the 508s were just coming in!). And when I retired most SWR suburban trains were still 10-car, so I got out at a good time!

Yes, I also feel they won the franchise on a big con, promises that never happened. Also some real twisting of facts eg blaming delays on covid, when the schedule they had agreed to had 30% of trains in service when pandemic struck in Feb-March 2020

There’s no way a 701 or 707 has poorer acceleration than a 450.

The 450s are limited to about 70% of their design power, from memory about 1500hp, instead of their rating of nearer 2100hp due to substation weaknesses, if unrestricted the 450s acceleration is about 1.2 or 1.3m/s2

Earlier this afternoon I was waiting on P1 at Richmond for my train home and a Class 701 drew in on test (didn't get the number). What really struck me was the impressive acceleration away from the station and on damp rails. A complete contrast to the pair of staggering old 455s a few minutes before it.

Won't really get any timetabled acceleration until there is no longer any old slow 455s around. The current timetable is heavily padded, it is slower than the LSWR electric timetable over 100 years ago, and the LSWR torpedo electric units had lower top speed of only 55mph. Remains to be seen if the 701 timetable will remain slower than a century ago.

 

[OneTrackMinded]

performance quoted for 707, 444 and 450 are evidently way overstated

Can't speak for the 444 and 450 as others have already just mentioned as I was typing this out that there's some sort of software limitation, but the 707s are definitely faster. Might be wrong in saying this but I believe they have a higher max power output as well, so would make sense.

 

[Goldfish62]

The 450s are limited to about 70% of their design power, from memory about 1500hp, instead of their rating of nearer 2100hp due to substation weaknesses, if unrestricted the 450s acceleration is about 1.2 or 1.3m/s2

That would make them around 50% more accelerative than a 717 on AC overhead (0.85), a unit which is geared for high acceleration, when it's acknowledged that performance on AC will always be superior to DC.

My hunch is that maybe the 707 is a bit ahead of the 701, (but certainly not as good as a 720, which is 0.8), then after the 701 come the 450, then 444, followed at the bottom of the pile by the 455 and 458/5, both of which seem to me to be equally sluggish.

The quote from Siemens about 1.0 is from 2005 and is in relation to all four car units inc AC. I still think for AC it's overstated as I really can't accept that a 350 accelerates faster than a 720.

Anyway, as interesting as all this is we're getting a bit OT and hopefully we might have the opportunity to judge for ourselves on Thursday. Or not...

PS If you want high performance the 2009TS Stock at 1.3m/s2 knocks the socks off the lot of them!

 

[Energy]

Acceleration isn't a number its a curve. If it was a constant value then the train speed with be linear with time.

 

[43096]

My hunch is that maybe the 707 is a bit ahead of the 701, (but certainly not as good as a 720, which is 0.8), then after the 701 come the 450, then 444, followed at the bottom of the pile by the 455 and 458/5, both of which seem to me to be equally sluggish.

But overall a 458/5 blitzes a 450 on meeting the timetable on the Reading road, simply because there have been ice ages that are shorter than a 450's door opening times. I'd also add that driving style makes a huge difference. Since the WorstGroup takeover it is no surprise that performance has got increasingly sluggish: no doubt importing the "Bristol School of Motoring" (aka "Bristol gnomes") from GWR.

 

[norbitonflyer]

Sorry to be the bearer of bad news, but 2U91 and 2U92 no longer appear on RTT for Thursday or Friday. A 5Q31 and 5Q32 appear in what appear to be similar paths (1026 from Waterloo, 1133 from Windsor) on Thursday only.

 

[TT-ONR-NRN]

Sorry to be the bearer of bad news, but 2U91 and 2U92 no longer appear on RTT for Thursday or Friday. A 5Q31 and 5Q32 appear in what appear to be similar paths (1026 from Waterloo, 1133 from Windsor) on Thursday only.

Oh no! I was so excited to see it enter service too.

 

[Mills444]

Shame I was in London that day too.

 

[D365]

No more Thursday ties in with what I am hearing…

 

[Goldfish62]

Acceleration isn't a number its a curve. If it was a constant value then the train speed with be linear with time.

Of course it's a number, otherwise it wouldn't be possible to make a comparison between rates.

Sorry to be the bearer of bad news, but 2U91 and 2U92 no longer appear on RTT for Thursday or Friday. A 5Q31 and 5Q32 appear in what appear to be similar paths (1026 from Waterloo, 1133 from Windsor) on Thursday only.

Oh well.

So 2024 it is then. Or maybe 2025...

 

[dctraindriver]

How bizarre, if you’re suggesting the 701s should not utilise their fast acceleration and instead pull out extra cautiously? Surely not?

As with the 707s acceleration is very quick, so much so that where in previous stocks you’d open fully and remain within that specific speed limit for that part of the network, it’ll be easy to over speed if you fully open on a 701/707, so many drivers won’t take full power when leaving certain stations.

 

[Goldfish62]

As with the 707s acceleration is very quick, so much so that where in previous stocks you’d open fully and remain within that specific speed limit for that part of the network, it’ll be easy to over speed if you fully open on a 701/707, so many drivers won’t take full power when leaving certain stations.

Surely that's the same for any train anywhere.

Anyway, moving back to 701s, I think it's probably safe to say, as some have predicted, no soft launch this year.

So, 2023 has seen a big step forwards in that the trains are now ready for passenger service at long last, but a step backwards given that despite having years to deal with it a training programme has not been agreed!

 

[NSEWonderer]

Do keep in mind that according to the stats, the 701 is the slowest accelerating aventra (0.7), and the 707s which were in service a while ago did 0.85. The 450s and 444s do 1.0 for reference.

Who's stats are those? Alstoms? Or estimated as manufacturers can be quite Conservative.

 

[Goldfish62]

Who's stats are those? Alstoms? Or estimated as manufacturers can be quite Conservative.

From what I can find from Googling, the 701 is a quote from Modern Railways. I can't find anything for the 707. The nearest is the 717 at 0.85 and that is both AC and geared for higher acceleration than the 707. There's nothing quoted for 450 or 444, just a bland 1.0 quoted on a Siemens doc from 2005 for all four car Desiro UKs, both AC and DC. Obviously inaccurate given AC's superior acceleration.

You also have to remember with these things that acceleration is not constant throughout the speed profile. The Class 80x is often quoted as having superior acceleration on diesel to the HST. That's only true up to around 40 mph, when the HST overtakes.

I'd therefore takes all these quotes with an enormous pinch of salt. It's the overall rate of acceleration through the normal operational speed profile that matters.

 

[Energy]

Of course it's a number, otherwise it wouldn't be possible to make a comparison between rates.

Sit on a train going from 90mph to 100mph and tell me its accelerating at the same rate as from 20mph to 30mph.

You can express it as a number, like peak acceleration, average acceleration or time to a certain speed. But whoever makes spec tables is often lazy and just puts it as "Acceleration".

I'd expect the 1.0m/s2 figure quoted for the 450s is the peak acceleration as it came from Siemens promotional material.

 

[onlyspaceghost]

A 701 just passed my train at Basingstoke 11:37, it stopped briefly before continuing. I couldn't tell if it was carrying passengers but I assume not as I couldn't find it on RTT. I've been seeing these trains at Clapham Jn forever so my jaw dropped when suddenly out of the window a 701 just rocks up xD

 

[Goldfish62]

A 701 just passed my train at Basingstoke 11:37, it stopped briefly before continuing. I couldn't tell if it was carrying passengers but I assume not as I couldn't find it on RTT. I've been seeing these trains at Clapham Jn forever so my jaw dropped when suddenly out of the window a 701 just rocks up xD

Same with me yesterday as it pulled into Richmond on the time of the already announced Reading service!

 

[NSEWonderer]

From what I can find from Googling, the 701 is a quote from Modern Railways. I can't find anything for the 707. The nearest is the 717 at 0.85 and that is both AC and geared for higher acceleration than the 707. There's nothing quoted for 450 or 444, just a bland 1.0 quoted on a Siemens doc from 2005 for all four car Desiro UKs, both AC and DC. Obviously inaccurate given AC's superior acceleration.

You also have to remember with these things that acceleration is not constant throughout the speed profile. The Class 80x is often quoted as having superior acceleration on diesel to the HST. That's only true up to around 40 mph, when the HST overtakes.

I'd therefore takes all these quotes with an enormous pinch of salt. It's the overall rate of acceleration through the normal operational speed profile that matters.

Agreed but I remember people quoting the starting acceleration if the 345s are quite slow and real world they turned out to be rapid. 701 can't be that much slower than the much heavier 444s.

 

[Goldfish62]

Agreed but I remember people quoting the starting acceleration if the 345s are quite slow and real world they turned out to be rapid. 701 can't be that much slower than the much heavier 444s.

I certainly can't accept that they're any slower than the lard***e 444s and I'm sure will turn out to be very considerably more nippy.

Yes, the 345s rocket along. At any speed you can easily feel the kick of the acceleration when power is applied.

 

[Big Jumby 74]

Whatever the ins and outs of 701 acceleration, I would think there won't be any recasting of the inner timetable - and I have no idea if there ever will be I should add - until the slowest kids on the block (455's) have all retired, otherwise a mockery would be made of the public schedules. Adjusting (speeding up) of individual services during the period of 701 introduction, based on which services the newbie's are allocated to work, would (should) also never be entertained, so the full potential of the 701's, be it acceleration or point to point won't be appreciated (publicly) until the entire inner service is worked by them. That's my guess anyway!

 

[Peter Sarf]

Whatever the ins and outs of 701 acceleration, I would think there won't be any recasting of the inner timetable - and I have no idea if there ever will be I should add - until the slowest kids on the block (455's) have all retired, otherwise a mockery would be made of the public schedules. Adjusting (speeding up) of individual services during the period of 701 introduction, based on which services the newbie's are allocated to work, would (should) also never be entertained, so the full potential of the 701's, be it acceleration or point to point won't be appreciated (publicly) until the entire inner service is worked by them. That's my guess anyway!

Exactly. Even if the units stick to their correct diagrams there is very little to benefit from speeding up some trains as all the rest will very quickly be in the way.

Also a proportion of the better acceleration capabilities of the 701s will always be unused - kept in reserve. For when a train has ended up late and needs to make up time so as not to be in the way of the surrounding services. There will also be a desire to save energy until demand overrides such things. How much and how true I know not.

 

[SWT_USER]

I can't see a recast of the timetable any time soon, even when the 701's are all in service.

The trains were ordered when capacity was at a premium and there was a need for extra services to be squeezed in. SWR no longer run enough trains for this to be worth doing, and given they struggle to organise timetables for strikes/ short notice engineering work I can't imagine they would be able to re do the whole timetable.

 

[Goldfish62]

I can't see a recast of the timetable any time soon, even when the 701's are all in service.

The trains were ordered when capacity was at a premium and there was a need for extra services to be squeezed in. SWR no longer run enough trains for this to be worth doing, and given they struggle to organise timetables for strikes/ short notice engineering work I can't imagine they would be able to re do the whole timetable.

Are you really suggesting that, uniquely, SWR is incapable of recasting timetables?! Beside which extra services ARE now needed.

But then I suppose if they're incapable of introducing new trains anything's possible...