GWR Class 769 information. (Units no longer with GWR - Off Lease March 23)

[Bald Rick]

You're saying there would be sufficient recharging capability when running on 3rd rail and turning around at Gatwick and Reading.

Yes. They spend more time on the third rail than off it.

But what would be the life-expectancy before the batteries fall short? 1yr, 10yrs or longer?

I don’t know - what’s the life expectancy of the batteries in Merseyrail‘s Stadlers? Or TfWs tram trains? Or any engine under a DMU?

 

[jackot]

You're saying there would be sufficient recharging capability when running on 3rd rail and turning around at Gatwick and Reading.

I'm surprised.

Without turning this into a thread about batteries, the power is certainly there. If the 3rd rail (at least between Reading and Wokingham and then Aldershot South and Shalford) is enough to cope with a 10-car Juniper or a 12-car Desiro, I would imagine there is enough power to provide for 3-4 cars worth of traction motors, and enough extra to recharge the batteries. IIRC there are some power constraints between Reigate and Redhill which limit services to 4-car (so it might mean minimal charging can take place there) but there is still plenty of time to recharge from Redhill to Gatwick and during their turnaround at either station.

 

[Bald Rick]

Without turning this into a thread about batteries, the power is certainly there. If the 3rd rail (at least between Reading and Wokingham and then Aldershot South and Shalford) is enough to cope with a 10-car Juniper or a 12-car Desiro, I would imagine there is enough power to provide for 3-4 cars worth of traction motors, and enough extra to recharge the batteries. IIRC there are some power constraints between Reigate and Redhill which limit services to 4-car (so it might mean minimal charging can take place there) but there is still plenty of time to recharge from Redhill to Gatwick and during their turnaround at either station.

oh there’s plenty of capacity in the third rail. What’s less clear is if there is sufficient capacity in the substations. I’m reasonably sure there is at the Reading and Gatwick ends, and around Guildford, less sure about Pink’s Hill (west of Guildford) to Ash. However, if there isn’t, there wouldnt be capacity for more electric only stock either, so at worst it’s the same problem.

 

[The Ham]

Budget cuts - the savings that the DfT want off the TOCs budgets for 2023/4 are eye watering. They are looking for opportunities to bin stock at lease end dates and the GWR 769 were an easy hit.

If it wasn’t for these cuts, GWR would have probably been told to soldier on with them. As it is, they have now gone some way to meeting their 2023/4 cuts target.

Yet GWR are one of the better TOC's at recovering from COVID as period 13 of 19/20 they were paid £53.6 million whilst period 7 of 21/22 they were paid £41.3 million (having taken by over half from £98.9 million in period 1 of 21/22). There's not many which were being paid less between the start/end and the average over 21/22 was only about half (£632 million to £318 million).

 

[Minstral25]

oh there’s plenty of capacity in the third rail. What’s less clear is if there is sufficient capacity in the substations. I’m reasonably sure there is at the Reading and Gatwick ends, and around Guildford, less sure about Pink’s Hill (west of Guildford) to Ash. However, if there isn’t, there wouldnt be capacity for more electric only stock either, so at worst it’s the same problem.

Locally Network Rail and GTR keep telling us that there is no power capacity for 8/12 coach trains to Reigate without a very expensive upgrade to the power system.
Also, that the slow lines from Redhill to Gatwick have no spare power capacity for extra trains.
I suspect it’s just an excuse but it would mean that an upgrade might be needed somewhere to run battery trains. Hope not as I agree that North Downs is perfect for Battery trains otherwise.

 

[DelW]

Locally Network Rail and GTR keep telling us that there is no power capacity for 8/12 coach trains to Reigate without a very expensive upgrade to the power system.
Also, that the slow lines from Redhill to Gatwick have no spare power capacity for extra trains.
I suspect it’s just an excuse but it would mean that an upgrade might be needed somewhere to run battery trains. Hope not as I agree that North Downs is perfect for Battery trains otherwise.

Indeed, I think it was stated some years ago (possibly in this thread or the one about the then-proposed 3tph timetable on the NDL) that 769s would have to run on diesel between Redhill and Gatwick as the power supply wouldn't be adequate. Maybe the present service reductions would change that assessment.

 

[GoneSouth]

Given the often mentioned lack of money, I cannot understand why any more is being wasted on these trains. Who wants a train that develops a fault every 1200 miles? They'll have to keep some 165s at Reading to stand in the failures. Either that or cancel the rest of the diagram. Does GWR seriously think its 769s on intensive 500 mile diagrams will do better than the others?

Probably cheaper just to can the whole project, GWR then fail to run a diagram or 2 and let whoever stumps up the cash for delay repay foot pay the Bill.

The service on the North Downs is based from the Reading end, providing early morning connections from the Western (including out the sleeper) to flights from Gatwick. GWR is the only operator with stabling and traincrew at the Reading end so no it wouldn’t make sense to transfer it to an operator at the wrong end of the route.

Blimey would I put myself at risk of missing an earlyish fight from Gatwick by using the sleeper AND the connecting GWR service from Reading? Not a chance, hotel at Gatwick for me!

 

[zwk500]

Probably cheaper just to can the whole project, GWR then fail to run a diagram or 2 and let whoever stumps up the cash for delay repay foot pay the Bill.

Blimey would I put myself at risk of missing an earlyish fight from Gatwick by using the sleeper AND the connecting GWR service from Reading? Not a chance, hotel at Gatwick for me!

I'd be astonished if the number of people connecting off the sleeper onto a Gatwick trains was more than single figures for the year. Reading residents may use it for early morning flights a bit more, but the proportion of people using it at that time of the morning must be miniscule.

 

[norbitonflyer]

oh there’s plenty of capacity in the third rail. What’s less clear is if there is sufficient capacity in the substations. I’m reasonably sure there is at the Reading and Gatwick ends, and around Guildford, less sure about Pink’s Hill (west of Guildford) to Ash. However, if there isn’t, there wouldnt be capacity for more electric only stock either, so at worst it’s the same problem.

A substation has to be designed to cope with a train drawing full power, whether that is to move the train directly or to charge its batteries. As a train does not spend much time drawing full power, there should be ample capacity to charge batteries - tyere may need to be some clever stuff to ensure that if there are several trains in the area drawing power, battery charging takes second place to trains accelerating.

The NDL, despite its name, is not very hilly, but it does have lots of stops, so regenerative braking may also be useful in keeping the batteries topped up.

 

[JonathanH]

The NDL, despite its name, is not very hilly, but it does have lots of stops, so regenerative braking may also be useful in keeping the batteries topped up.

There is a fairly substantial climb up to the summit around Gomshall, albeit just a prolonged up and down rather than multiple climbs and falls.

 

[AM9]

A substation has to be designed to cope with a train drawing full power, whether that is to move the train directly or to charge its batteries. As a train does not spend much time drawing full power, there should be ample capacity to charge batteries - tyere may need to be some clever stuff to ensure that if there are several trains in the area drawing power, battery charging takes second place to trains accelerating.

It would be easy to prevent charging when the line voltage was below a certain level, thereby keeping the current draw within that expected for the paths on the line. Such a facility could easily be activated by software (including setting the actual voltage at which charging was stopped).

 

[paul1609]

I don’t know whether to be happy or sad, but at least the decision is made.



This is not correct

The size of the batteries required to power a 250 seat train over the unelectrified section of the North Downs Line on a typical diagram would be rather smaller than the size of the engines and fuel tank required to power a 250 seat diesel train. (You’d need roughly 5-8 tonnes of battery pack).

There would be no cost or time penalties for the charging infrastructure. It’s already installed, between Reading and Wokingham, Aldershot South Junction and Shalford Junction, and Reigate to Gatwick.

Is this actually modelled and tested though. Network Rail and its predecessors were already embarassed when the TOCs tried to introduce the Electrostar and Desiro on the dc network only to find out there was insufficient power. I understand from GTR that to this day the Gatwick Express stock is software limited on dc because the subsequent upgrade was the minimum possible and I understand that the SWT desiros are even more severely restricted. I understand that some of the dc electrified lines dont have enough spare power capacity for the existing diesel trains to be replaced with straight electric units let alone units fast charging batteries for off grid running. (South Croydon to Hurst Green, Cosham to St Denys).

 

[Bald Rick]

A substation has to be designed to cope with a train drawing full power, whether that is to move the train directly or to charge its batteries. As a train does not spend much time drawing full power, there should be ample capacity to charge batteries - tyere may need to be some clever stuff to ensure that if there are several trains in the area drawing power, battery charging takes second place to trains accelerating.

not quite - substations need to be designed for maximum load from all trains that might be in section at any one time (for a limited time), and have capacity to cool down after that before the next max peak load. Even a 4 car train can make a difference, but as I said upthread it shouldn’t be an issue in most places.

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Is this actually modelled and tested though.

I know, I’ve done it

 

[D6130]

It would be easy to prevent charging when the line voltage was below a certain level, thereby keeping the current draw within that expected for the paths on the line. Such a facility could easily be activated by software (including setting the actual voltage at which charging was stopped).

Would that not create the danger of the train's batteries running-out of charge when travelling through a non-electrified section?

 

[zwk500]

Would that not create the danger of the train's batteries running-out of charge when travelling through a non-electrified section?

If necessary you can have minimum charge levels before leaving the juiced section. May need 5 mins sitting at Reigate to charge up but better than coasting to a stop.

 

[Fincra5]

So basically... drop the 769s and go for some new 777s with batteries etc...

 

[Deepgreen]

If they are sized correctly, there's no reason why they wouldn't give similar service to those in a regularly used car. It's the control of the charge/discharge cycle and the operating temperature of the battery that impacts most on their working life. We should presume that on a large installation that would have well-defined duty cycles, ant temperatures would be well known in the design phase.

Indeed, and another issue occurs to me (that may not apply here) - my PHEV car that was delivered in July got a 38 mile range then (in hot summer weather), but now is more typically 28 miles, owing to the very low temperatures precluding charging to the same degree.

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So basically... drop the 769s and go for some new 777s with batteries etc...

Possibly, and my concern here, too, is that some have been saying that valuable information has been gained from the years-long saga about modifications to old stock in this way, but I strongly suspect that no similar retro-fitting exercise would be risked in future, as opposed to procuring new stock, rendering that experience pointless. I could be wrong.

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As we have learnt over the last few years in the west, just because demand justifies it, doesn't mean you will get it. Short forming is very quickly becoming the norm, and the Cardiff to Portsmouth route, which is longer and very often very busy is a prime example of a service which shouldn't be short formed but often is.

I know, but my comment was in response to JonathanH's assertion that demand on the NDL did not justify the 769s anyway.

 

[YSTrains]

How likely can the decision be overturned. I really wanted to see these units enter service.

 

[AM9]

Indeed, and another issue occurs to me (that may not apply here) - my PHEV car that was delivered in July got a 38 mile range then (in hot summer weather), but now is more typically 28 miles, owing to the very low temperatures precluding charging to the same degree.

Your PHEV would presumably have a shorter range in the winter owing to:

additional use of lighting​

use of interior heating​

if the battery does not have full temperature control, a reduced efficiency when below it's optimum operating temperature. A bi-mode (electro-battery) train would probably have a fully managed battery temperature control system in order to maximise it's performance and working life.[/QUOTE]

Possibly, and my concern here, too, is that some have been saying that valuable information has been gained from the years-long saga about modifications to old stock in this way, but I strongly suspect that no similar retro-fitting exercise would be risked in future, as opposed to procuring new stock, rendering that experience pointless. I could be wrong.

I believe that the 769 programme has brought some useful information about scheduling and running bi-mode powered trains, and with that, a better understanding of
maintaining them and key issues in specifying them when procuring from a commercial manufacturer.
There is probably scope for modifying other rolling stock, e.g. the talk of some Electrostar sets with batteries. The issue is whether buying new can always be funded, - see other threads here raising the issue that the opportunities to buy may not be as they were 5-10 years ago.

 

[Deepgreen]

Your PHEV would presumably have a shorter range in the winter owing to:

additional use of lighting​

use of interior heating​

if the battery does not have full temperature control, a reduced efficiency when below it's optimum operating temperature. A bi-mode (electro-battery) train would probably have a fully managed battery temperature control system in order to maximise it's performance and working life.

The car displays the range available on entering the vehicle - so not taking lighting, heating or anything else into account. As far as I can tell it is purely because of the far lower temperatures. For example, I got into it just now (at 0C) and the dashboard showed "100% charged, 27 miles range". In August (at 27C) I usually saw, "100% charged, 38 miles range". I wondered if a similar range reduction for cold batteries would apply to trains, but temperature control may mitigate that.


[/QUOTE]

 

[reddragon]

A simple train with oversized LFP batteries, running to a programmed charge / discharge cycle would have no issues whatsoever.

If it works on BYD buses all day / all year, I'm sure a mostly electrified line with a couple of gaps would not be the remotest of challenges!

Sounds like time to close the thread, apart from maybe a scrapping ex GWR class 769s thread or a speculative thread of where they may end up!

 

[Steddenm]

I'd be astonished if the number of people connecting off the sleeper onto a Gatwick trains was more than single figures for the year. Reading residents may use it for early morning flights a bit more, but the proportion of people using it at that time of the morning must be miniscule.

You'd be surprised with the Sleeper-Gatwick passenger numbers.

A few times I've been on the Sleeper from Penzance to Reading and a lot of people have got off and then got the Gatwick train with large suitcases.

Also there's a weird flow of Cornwall to Southampton for the cruise ships on the Sleeper, again changing at Reading in the early morning.

 

[WizCastro197]

You'd be surprised with the Sleeper-Gatwick passenger numbers.

A few times I've been on the Sleeper from Penzance to Reading and a lot of people have got off and then got the Gatwick train with large suitcases.

Also there's a weird flow of Cornwall to Southampton for the cruise ships on the Sleeper, again changing at Reading in the early morning.

Did you stay on the train until Gatwick?

 

[Steddenm]

Did you stay on the train until Gatwick?

I do yes and it's usually quite a good turn out (for the days it wasn't terminated at Guildford or Redhill)

 

[thelongestroad]

So basically... drop the 769s and go for some new 777s with batteries etc...

Or most likely drop the 769s and use 165s for the rest of the millenium.

 

[WizCastro197]

I do yes and it's usually quite a good turn out (for the days it wasn't terminated at Guildford or Redhill)

Well North Downs serves a lot of Surrey's smaller towns so can be a good link. To be fair, I can imagine those from Guildford/Redhill/Reigate/Dorking going to Reading to board other GWR services whether it be a regular train or the sleeper rather than traverse through London. Not all trains go to Gatwick Airport however.

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Or most likely drop the 769s and use 165s for the rest of the millenium.

165s can't go on for ever but they still are alright for the foreseeable future, providing they are refreshed/refurbished accordingly in lieu of the 769s scrapped introduction.

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How likely can the decision be overturned. I really wanted to see these units enter service.

Up to the DfT isn't it, I say their decision seems pretty final considering they are now firmly in charge and the let down the attempted introduction has been.

 

[DelW]

I'd be astonished if the number of people connecting off the sleeper onto a Gatwick trains was more than single figures for the year. Reading residents may use it for early morning flights a bit more, but the proportion of people using it at that time of the morning must be miniscule.

I've caught the first train from Guildford to Gatwick a few times to catch an early flight, and been surprised just how busy it was.

The NDL, despite its name, is not very hilly, but it does have lots of stops, so regenerative braking may also be useful in keeping the batteries topped up.

Really? According to my gradient profile, almost all of the line from Shalford (just south of Guildford) to Redhill is at something near to 1:100.

 

[fgwrich]

How likely can the decision be overturned. I really wanted to see these units enter service.

Good luck, unless you've got several spare millions down the back of your sofa, you wont be seeing them on the Western. Particularly given the fact that dropping the 769s makes a significant dent in the spending cuts the DfT has instructed GWR to make.

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I've caught the first train from Guildford to Gatwick a few times to catch an early flight, and been surprised just how busy it was.

Really? According to my gradient profile, almost all of the line from Shalford (just south of Guildford) to Redhill is at something near to 1:100.

Indeed, you can see some of the gradient in this cab view (from Guildford to Redhill):

 

[Wyrleybart]

165s can't go on for ever but they still are alright for the foreseeable future, providing they are refreshed/refurbished accordingly in lieu of the 769s scrapped introduction.

What was their estimated life after they had moved west ?

 

[JonathanH]

What was their estimated life after they had moved west ?

The recent extensions for leases for GWR DMUs were to 2028, by which time they are 35-36 years old, having entered service between April 1992 (first 165/1) and September 1993 (final 166)