Class 701 'Aventra' trains for South Western Railway

[SEtrains]

What 701 is getting dragged to Eastleigh today?https://www.realtimetrains.co.uk/service/gb-nr:K00463/2024-02-16/detailed#allox_id=0

 

[3973EXL]

701530

Realtime Trains | 5Q10 0912 Derby Litchurch Lane to Eastleigh Trsmd | 16/02/2024

Real-time train running information for 5Q10 0912 departure from Derby Litchurch Lane to Eastleigh Trsmd on 16/02/2024. From Realtime Trains, an independent source of train running info for Great Britain.

www.realtimetrains.co.uk

 

[SEtrains]

701530

Realtime Trains | 5Q10 0912 Derby Litchurch Lane to Eastleigh Trsmd | 16/02/2024

Real-time train running information for 5Q10 0912 departure from Derby Litchurch Lane to Eastleigh Trsmd on 16/02/2024. From Realtime Trains, an independent source of train running info for Great Britain.

www.realtimetrains.co.uk

Thanks

 

[OneTrackMinded]

That is a maximum acceleration rate, the acceleration rate is non linear and varies with speed (two separate V^2 components involved in the non-linearity). The shape of the whole curve across the relevant speed range is what matters not the gradient of the steepest bit of the curve alone and the aventra curves is slightly flatter than others so while the peak value may not be as high the average is better.

With well designed modern 3phase traction motors & traction electronics and decent number of motored axles, gearing makes very little difference for max 75mph with gearing optimised for 75mph or 100mph and the excellent Aventra traction motor cooling really helps here.

That's very interesting, thanks for the insight.

 

[norbitonflyer]

701043 on yet again today. At this rate it will be worn out before most of its classmates have enetered service

 

[SEtrains]

More 701(s) are coming out of storage today.69008 doing the duties

https://www.realtimetrains.co.uk/service/gb-nr:R01917/2024-02-19/detailed light loco

Realtime Trains | 5Q76 1122 Marchwood Mod Gbrf to Eastleigh Trsmd | 19/02/2024

Real-time train running information for 5Q76 1122 departure from Marchwood Mod Gbrf to Eastleigh Trsmd on 19/02/2024. From Realtime Trains, an independent source of train running info for Great Britain.

www.realtimetrains.co.uk

Loco+701(s)

 

[norbitonflyer]

No 1155 departure running today. The 1025 is diagrammed for 701043 again.

No sign of the second diagram on RTT any day this week

 

[Peter Mugridge]

701 043 again today ( 19th )...

 

[3973EXL]

701057

Realtime Trains | 5Q76 1122 Marchwood Mod Gbrf to Eastleigh Trsmd | 19/02/2024

Real-time train running information for 5Q76 1122 departure from Marchwood Mod Gbrf to Eastleigh Trsmd on 19/02/2024. From Realtime Trains, an independent source of train running info for Great Britain.

www.realtimetrains.co.uk

 

[Energy]

With well designed modern 3phase traction motors & traction electronics and decent number of motored axles, gearing makes very little difference for max 75mph with gearing optimised for 75mph or 100mph and the excellent Aventra traction motor cooling really helps here.

The Aventras are quite unique in their external blower cooling for motors.

Powered axles is an interesting point, the Aventras have 1 powered axle per bogey but consequently have most (4/5 typically) bogeys motored. The 745s manage excellent acceleration despite only 8 motored axles, each with 600kw motors.

 

[hwl]

The Aventras are quite unique in their external blower cooling for motors.

External blowers are effectively universal for locomotives so not that unusual overall just for EMUs, a big step for low speed cooling and ensuring effective cooling across the entire motor speed range.

Powered axles is an interesting point, the Aventras have 1 powered axle per bogey

No, Aventras have zero or two power axles per bogie never 1, Voyagers and meridian have 1 and Electrostars have 0, 1 or 2 depending on which class number of vehicles per unit.

The 5car 701s have 8 motored axles (4 bogies) - 40% and the 10car 16 motored axles (8 bogies).
710 have 2 motored axles per car (1 bogie), 50% (so 8/10 for 4/5car)
720 & 730 have 10 motored axles (50%) with 0 motor bogies (1car),1 (3cars) or 2 (1 car) motor bogies per car
345 have 20 of 36 axles motored (55.5%) with 0 (1car),1 (6cars) or 2 (2 car) motor bogies per car

but consequently have most (4/5 typically) bogeys motored. The 745s manage excellent acceleration despite only 8 motored axles, each with 600kw motors.

Efficient deceleration is not the mirror image of good acceleration where you have to assume much lower effective adhesion

 

[OneTrackMinded]

The 5car 701s have 8 motored axles (4 bogies) - 40% and the 10car 16 motored axles (8 bogies).

I wonder why the decision was made for the 701s to have the lowest percentage of motored axles considering they perform similar duties to the 710s (commuter and metro) which have 50%? Obviously not something necessarily isolated to the DC thing considering 710s are dual voltage

 

[hwl]

I wonder why the decision was made for the 701s to have the lowest percentage of motored axles considering they perform similar duties to the 710s (commuter and metro) which have 50%? Obviously not something necessarily isolated to the DC thing considering 710s are dual voltage

701s are multiples of 5 car only not 4 or 5car with the option to easily lengthened to 5 required for the 710s, hence 1 motor bogie per vehicle makes the 710s more easily scalable. And more motors make sense with AC if 710s were DC only then it would be less likely to have 50%. The weight reduction makes performance the difference smaller.

 

[OneTrackMinded]

701s are multiples of 5 car only not 4 or 5car with the option to easily lengthened to 5 required for the 710s, hence 1 motor bogie per vehicle makes the 710s more easily scalable. And more motors make sense with AC if 710s were DC only then it would be less likely to have 50%. The weight reduction makes performance the difference smaller.

Forgot about the weight reduction. Out of interest, how much power output does each motored axle have?

 

[hwl]

Forgot about the weight reduction. Out of interest, how much power output does each motored axle have?

265kW max.

Desiro and Electrostar 250kW
Desiro City 200kW

 

[OneTrackMinded]

265kW max.

Desiro and Electrostar 250kW
Desiro City 200kW

Desiro Cities like the 707 must have more powered axles to achieve the higher max acceleration of 0.85m/s/^2 then if they're only 200kW and the 701 is 265kW at 0.7/m/s^2 max acceleration

 

[hwl]

Desiro Cities like the 707 must have more powered axles to achieve the higher max acceleration of 0.85m/s/^2 then if they're only 200kW and the 701 is 265kW at 0.7/m/s^2 max acceleration

No 707s are 8 axles (40%) like 5 car 701.
717 are 12axles (50%). 700s are all 50%.

Siemens just put a higher peak max acceleration rather on the spec sheet. Cheekily the 0.85 may not be on DC! The assumptions behind those rates are stated and they may not be directly comparable.

In reality 701s and 707s have a lot of software adjustment of performance to deal with variation in third rail voltage and available current than Electrostar or Desiro so in reality reading too much in to hardware differences is possible.

 

[Energy]

No, Aventras have zero or two power axles per bogie never 1, Voyagers and meridian have 1 and Electrostars have 0, 1 or 2 depending on which class number of vehicles per unit.

The 5car 701s have 8 motored axles (4 bogies) - 40% and the 10car 16 motored axles (8 bogies).
710 have 2 motored axles per car (1 bogie), 50% (so 8/10 for 4/5car)
720 & 730 have 10 motored axles (50%) with 0 motor bogies (1car),1 (3cars) or 2 (1 car) motor bogies per car
345 have 20 of 36 axles motored (55.5%) with 0 (1car),1 (6cars) or 2 (2 car) motor bogies per car

Interesting, I'm surprised Bombardier managed two motors on a lightweight bogey.

Though looking at the SF7000 it manages 2 motors per bogie, no idea why I thought it was only 1 per bogie on Aventra (the Flexx Eco doesn't have many photos online).

Meanwhile, Hitachi is comparatively poor with outside frame bogeys on the 385s and 80Xs despite having the same or lower-powered motors.

I'd imagine that the 345s have an interesting transformer and traction converter setup with their length.

Efficient deceleration is not the mirror image of good acceleration where you have to assume much lower effective adhesion

Fair enough, I guess for Stadler it's less of a priority on intercity and (slower) regional routes.

 

[SEtrains]

I’ve noticed that 701 043 has been used the most on the public class 701 services. Is there any reason why this is?

 

[norbitonflyer]

I’ve noticed that 701 043 has been used the most on the public class 701 services. Is there any reason why this is?

Indeed. Don't know of any reason unless it's because it has the commemorative logo on it.

028 -3 outings
037 - 5 outings
039 - 8 outings (+1 cancelled because of disruption at Wraysbury)
043 - 13 outings (including today)

 

[hwl]

Interesting, I'm surprised Bombardier managed two motors on a lightweight bogey.

Removing the cooling fan from the shaft and having external (to the bogie) cooling shortens the rotor shaft (and hence external motor) length and allows wheel mounted disc brakes on internal frame bogie the motored axles which Siemens can't do and to use tread brakes instead and Hitachi use outside frame motor bogies to have disc brake on motored axles.

Though looking at the SF7000 it manages 2 motors per bogey, no idea why I thought it was only 1 per bogey on Aventra (the Flexx Eco doesn't have many photos online). Meanwhile, Hitachi is comparatively poor with outside frame bogeys on the 385s and 80Xs despite having the same or lower-powered motors.

I'd imagine that the 345s have an interesting transformer and traction converter setup with their length.

All Aventras have "interesting" set ups compared to traditional ways. Each traction electronics box has 4 or 6 traction inverters (1 per motor) which feed bogies on multiple vehicles. Siemens and Hitachi still mostly do the traditional traction electronics box and motors on the same vehicle which results in a mix of heavy and light vehicles.
Leading axles traditional suffer from lower adhesion, hence Bombardier's Aventra thinking makes not motoring leading bogies on units easier.

Fair enough, I guess for Stadler it's less of a priority on intercity and (slower) regional routes.

Exactly but Stadler are used to 15kV 16 2/3Hz supplies that often struggle with regen, so regen thinking isn't near the top of their list, more at the "after thoughts" end.

 

[Energy]

Exactly but Stadler are used to 15kV 16 2/3Hz supplies that often struggle with regen, so regen thinking isn't near the top of their list, more at the "after thoughts" end.

FLIRTs also tend to be quite short and they have fewer bogies, a 4-car electric-only FLIRT with only the end bogeys powered is still 40% as the rest are jacobs bogies. The 745s are unusual for having a lot of normal bogies and their length.

The high-power motors make up for the high axle weight though as you said they'll still struggle for regen.

Removing the cooling fan from the shaft and having external (to the bogie) cooling shortens the rotor shaft (and hence external motor) length and allows wheel mounted disc brakes on internal frame bogie the motored axles which Siemens can't do and to use tread brakes instead and Hitachi use outside frame motor bogies to have disc brake on motored axles.

I presume its still forced air but using ducts from the body to the motors?

All Aventras have "interesting" set ups compared to traditional ways. Each traction electronics box has 4 or 6 traction inverters (1 per motor) which feed bogies on multiple vehicles. Siemens and Hitachi still mostly do the traditional traction electronics box and motors on the same vehicle which results in a mix of heavy and light vehicles.
Leading axles traditional suffer from lower adhesion, hence Bombardier's Aventra thinking makes not motoring leading bogies on units easier.

Interesting, thanks for the detail.

 

[hwl]

FLIRTs also tend to be quite short and they have fewer bogies, a 4-car electric-only FLIRT with only the end bogeys powered is still 40% as the rest are jacobs bogies. The 745s are unusual for having a lot of normal bogies and their length.

Less than 40% on an equivalent basis

The high-power motors make up for the high axle weight though as you said they'll still struggle for regen.

High axle load is bad for track access charges...

The weight isn't massive compared to a locomotive axle load so fingers crossed you get good adhesion, the Siemens / Bombardier strategy is quite good at mitigating against poor adhesion.

I presume its still forced air but using ducts from the body to the motors?

Yes, flexible concertina type bellows as used on locomotives for 7+ decades. You can spot the motor bogies from the presence of a small radial duct fan unit a few feet inboard of the bogie on the under carriage (sometime with an air compressor mounted next to it so it is only visible from one side)

Interesting, thanks for the detail.

 

[norbitonflyer]

028 -3 outings
037 - 5 outings
039 - 8 outings (+1 cancelled because of disruption at Wraysbury)
043 - 13 outings

Now 14: more than any other two units put together

 

[43OO4]

Just out of curiosity, what SR EMU designation are we giving these?

I propose 5AVN/10TRA, though I've seen 5FKD/10FKD too

 

[Sun Chariot]

Just out of curiosity, what SR EMU designation are we giving these? ... I've seen 5FKD/10FKD too

Cruel!
How about OOU (Out of Use)

 

[43OO4]

5CST/10CST (Cold Storage) has a nice ring to it

 

[Peter Mugridge]

How about 5UNC and 10UNC; the UNC referring to "Unicorn"...?

 

[norbitonflyer]

Boringly, 5ART and 10ART, as they are branded as Arterios. Less boringly, to be abbreviated to F(ive)ART and T(en)ART

 

[GW43125]

RTT reports 043 out today, but 037 has just flown past me at Clapham on its way back to Wimbledon Park.