Power Drawn: Class 444 vs Class 442

[SpacePhoenix]

How much more power does a 10 car class 444 draw from the 3rd rail then a 10 car class 442? There seems to have been a few problems with a substation somewhere around the Upwey area I believe

 

[Domh245]

Quite a bit more. Very rudimentary, but the 442 has 1,200kW traction motor power, whilst the 444 has 2000kW worth of power.

Like I said, rudimentary, because the 444 will be able to convert it's power more efficiently, and so will have less losses, and is current limited by it's TMS. But it also has an A-C system

 

[SpacePhoenix]

How much work and cost would be involved with upgrading the relevant substations to be able to handle all SWT services to Weymouth being either 10 car 444s or 12 car 450s?

How much power would a 444 draw if it wasn't limited by the TMS?

 

[MrC]

I think the problem with Poole-Weymouth is that any improvement requires a connection to the National Grid at the Weymouth end. I think the existing HV supply is stub fed from the Bournemouth/Poole end (Branksome?).

Then there's the question of why do we need 10x444 or 12x450 beyond Poole anyway? The existing trains are hardly busy to/from Poole even in the peaks and the intermediate stations can mostly only take 5x444 anyway. The 8x450 that occasionally runs once a day already blocks the LCs at Wool and Moreton when standing in the stations.

 

[cjmillsnun]

I seem to remember that that section used to be restricted to 5x442 at one point.

 

[edwin_m]

Quite a bit more. Very rudimentary, but the 442 has 1,200kW traction motor power, whilst the 444 has 2000kW worth of power.

Like I said, rudimentary, because the 444 will be able to convert it's power more efficiently, and so will have less losses, and is current limited by it's TMS. But it also has an A-C system

However the 444 is also heavier so will need more power to sustain the same performance. It is also capable of accelerating more rapidly at the top end of its speed range, thus using more power, but that might be prevented by the current limit. Although a 444 can regenerate, at the far end of the Weymouth line it's unlikely there will be another train motoring close enough by to accept the power.

This is the sort of issue that shows why the third rail is getting close to its limit on sections like this.

 

[RobShipway]

Apologies for taking this thread off subject, but if there is any spare HST sets after the Hitachi IEPs start to come into use on the ICGW, could some of those be used in 8 car formation for a quicker in between the class 44 service at all that just stops, Clapham, Winchester, Southampton Airport Parkway, Southampton, Brockenhuest, Bournemouth, Pool, Wareham and then finishing in Weymouth?

 

[Juniper Driver]

I seem to remember that that section used to be restricted to 5x442 at one point.

Well I never worked a ten in the 12 years I went down there.I did work an 8 car slammer once.Still restricted to 5 AFAIK but 10 can work with special permission.

 

[jopsuk]

They physically could but they won't. There is, after all, a distinct lack of capacity on the SWML in London

 

[RobShipway]

They physically could but they won't. There is, after all, a distinct lack of capacity on the SWML in London

But the lack of capacity is at the London End. I seem to remember during the 1990's when I lived down in Bournemouth, that there was Southampton - Weymouth trains due to there not being the capacity between Waterloo - Southampton, so surely extra trains even if they are diesel hauled but fast or semi-fast as per my post above could be placed between the class 444's going down to Weymouth?

 

[HSTEd]

Now a 444 versus a 4REP would be more interesting.....

 

[fgwrich]

Well I never worked a ten in the 12 years I went down there.I did work an 8 car slammer once.Still restricted to 5 AFAIK but 10 can work with special permission.

Indeed, the 19:03 last night was worked as a 10 car from Weymouth due to the increase in U.S. Passengers from the Weymouth Seafood Festival.

 

[notadriver]

However the 444 is also heavier so will need more power to sustain the same performance. It is also capable of accelerating more rapidly at the top end of its speed range, thus using more power, but that might be prevented by the current limit. Although a 444 can regenerate, at the far end of the Weymouth line it's unlikely there will be another train motoring close enough by to accept the power.



This is the sort of issue that shows why the third rail is getting close to its limit on sections like this.

I think the current limits applied to 444s severely limit their top end performance and they are no better than 442s when those were in their prime. When current limits are applied i think full power is available for initial pull away but rapidly tails off as speed increases to avoid overloading substations.

 

[hassaanhc]

Indeed, the 19:03 last night was worked as a 10 car from Weymouth due to the increase in U.S. Passengers from the Weymouth Seafood Festival.

I had been meaning to post that earlier but you beat me :P Although didn't know the exact reason why there were 10 cars (I thought it was due to disruption on the Bristol line).

19:03 Weymouth to London Waterloo due 21:49
Will be formed of 10 coaches instead of 5 between Weymouth and London Waterloo.
This is due to a large passenger flow.

 

[Steve14]

But the lack of capacity is at the London End. I seem to remember during the 1990's when I lived down in Bournemouth, that there was Southampton - Weymouth trains due to there not being the capacity between Waterloo - Southampton, so surely extra trains even if they are diesel hauled but fast or semi-fast as per my post above could be placed between the class 444's going down to Weymouth?

Lol you are making out as if HSTs have a 0-60 similiar to something like a Turbo. It takes time for the HST to reach its optimum speed and bearing in mind that the speed restrictions on the SWL, it's not worth having HSTs on them because as well as the acceleration downside in comparison to an electric, the costs for maintenance is high too which supports the point of them not operating on the lines out of Waterloo. Class 458s on the other hand would be good on a 10-12 car formation. Went on one from Windsor Riverside.

 

[RobShipway]

Lol you are making out as if HSTs have a 0-60 similiar to something like a Turbo. It takes time for the HST to reach its optimum speed and bearing in mind that the speed restrictions on the SWL, it's not worth having HSTs on them because as well as the acceleration downside in comparison to an electric, the costs for maintenance is high too which supports the point of them not operating on the lines out of Waterloo. Class 458s on the other hand would be good on a 10-12 car formation. Went on one from Windsor Riverside.

Whether it is HST's or another type of train, you still need the semi fast service as well as the stopping service as per my earlier posts on the 12th July.

 

[notadriver]

Lol you are making out as if HSTs have a 0-60 similiar to something like a Turbo. It takes time for the HST to reach its optimum speed and bearing in mind that the speed restrictions on the SWL, it's not worth having HSTs on them because as well as the acceleration downside in comparison to an electric, the costs for maintenance is high too which supports the point of them not operating on the lines out of Waterloo. Class 458s on the other hand would be good on a 10-12 car formation. Went on one from Windsor Riverside.

Just out of curiosity what do you think has better acceleration ? An HST or a Class 165 'turbo'?

 

[Steve14]

Lol you are making out as if HSTs have a 0-60 similiar to something like a Turbo. It takes time for the HST to reach its optimum speed and bearing in mind that the speed restrictions on the SWL, it's not worth having HSTs on them because as well as the acceleration downside in comparison to an electric, the costs for maintenance is high too which supports the point of them not operating on the lines out of Waterloo. Class 458s on the other hand would be good on a 10-12 car formation. Went on one from Windsor Riverside.

Just out of curiosity what do you think has better acceleration ? An HST or a Class 165 'turbo'?

Well seeing as I go in and out of Paddington. Been on a 166 which left at the same time as a HST, it left the HST behind up until old oak common where the HST was able to start hitting 100+. Acceleration from start; the 166 is quicker but straight run, HST hands down.

 

[notadriver]

Maybe they vary. Rail Express has 0-60 times suggesting a class 166 takes 102 seconds vs 96 seconds of an HST. If there was an advantage it was due to the turbo being shorter and accelerating earlier.

I recently took a trip myself on tube strike days of all days. Departing Paddington I was very pleasantly surprised with the HSTs acceleration and turn of speed. Not so impressed with the return journey on the 166 which seemed to take forever to reach 90 mph.

 

[antharro]

Although a 444 can regenerate, at the far end of the Weymouth line it's unlikely there will be another train motoring close enough by to accept the power.

Is regen braking currently enabled on the 444s? (and 450s?)

I recall one of the TOCs ran some short formed HSTs to get a speed advantage, but I don't remember who it was...

 

[SpacePhoenix]

I know that they won't now anyway because of their age but could they in the past have installed traction motors on the bogie of the coach of an HST nearest to the power car (like how Eurostars/Class 373s have traction motors on the bogie nearest their power cars)?

If they could have done it how much difference would it have made to their performance and fuel usage?

 

[AM9]

I know that they won't now anyway because of their age but could they in the past have installed traction motors on the bogie of the coach of an HST nearest to the power car (like how Eurostars/Class 373s have traction motors on the bogie nearest their power cars)?

If they could have done it how much difference would it have made to their performance and fuel usage?

Looking at that logically, the overall power available from the diesel engine would be the same and the coach-sited motors would increase the overall weight to move. There may be a slight increase in power that could be applied at low speeds, but I doubt that would make any overall difference except under very low adhesion conditions.
Eurostar 373s were designed that way from the start. Drawing more power from an off-board supply is far easier than trying to get more from a fixed rated diesel engine (and fuel supply).

 

[Emblematic]

Looking at that logically, the overall power available from the diesel engine would be the same and the coach-sited motors would increase the overall weight to move. There may be a slight increase in power that could be applied at low speeds, but I doubt that would make any overall difference except under very low adhesion conditions.
Eurostar 373s were designed that way from the start. Drawing more power from an off-board supply is far easier than trying to get more from a fixed rated diesel engine (and fuel supply).

Also bear in mind that the Mk3 coach is less than 1/2 the weight of the class 43, and even with the added mass of motors and motor bogie, these extra motored axles would suffer lack of adhesion and be very prone to wheel slip.
With DC motors, the near - universal approach is to put all of the motors under a single heavy vehicle with rest of the traction equipment, be that locomotive, or motor coach of EMU sets. AC motors, being smaller, better controlled and with better adhesion, have enabled the modern approach of distributing traction along the sets.
The exception was the TGV-PSE sets which had a motor bogie on the end carriages. However there was an equipment compartment (doubtless heavy) above the motors, not passenger seating. AC traction was trialled on two of the PSE sets, and used from TGV-A onward, including the Eurostar sets.

 

[swt_passenger]

Is regen braking currently enabled on the 444s? (and 450s?)

Since March 2012, all 450, 444 and 458s have been capable, according to SWT:

http://www.southwesttrains.co.uk/regenerative braking system.aspx

As far as I can tell, the Weymouth area is where all SWT's relevant classes have done their re-gen testing, presumably because the limited number of trains in the area is the worst case situation and forces the onboard system to inhibit the output to the third rail.

 

[notadriver]

Is regen braking currently enabled on the 444s? (and 450s?)

I recall one of the TOCs ran some short formed HSTs to get a speed advantage, but I don't remember who it was...

Wasn't it Cross Country that ran 2+5 HST sets?

 

[61653 HTAFC]

Wasn't it Cross Country that ran 2+5 HST sets?

There was a proposal by VXC to use reengineered 2+5 HST sets as part of "Operation Princess" but it never happened. FGW used a 2+2 set on the Golden Valley line years ago, but that was to cover for an unavailable sprinter I think.

 

[edwin_m]

Grand Central run 2+5 HSTs but I think that's more to match their passenger demand than for any concern about speed. Scotrail will be using 2+4 or 2+5 HSTs in the future but again not for speed reasons.