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Regarding your last sentence, I was always under the impression that the 319s/769s are capable of 100mph as that was the maximum speed they ran at when they worked on Thameslink.
The diesel performance isn't as good as what they can manage as 319s on electric. I actually wasn't noting a top speed, just noting that Bristol to Taunton has a higher line speed than any route they are intended to work on diesel on LTV services.
Regarding your last sentence, I was always under the impression that the 319s/769s are capable of 100mph as that was the maximum speed they ran at when they worked on Thameslink.
Or is it that when using diesel power, they can only go at a maximum of 75mph?
I originally though that which was reinforced by reports that they achieved 92mph on test at Loughborough, but it appears that the additional weight of the gensets and fuel in the driving cars has led NR to limit them to 75mph to which their track access charge is now probably aligned.
I think the extra weight has only posed a problem between Salford Crescent and Bolton due to the poor ground conditions caused by mining. When they worked TPE Anglo-Scottish routes the 185s were unable to use the MU Speed differentials on the same bit of track, thus were limited to 75mph with a brief spell of 80mph.
I think the extra weight has only posed a problem between Salford Crescent and Bolton due to the poor ground conditions caused by mining. When they worked TPE Anglo-Scottish routes the 185s were unable to use the MU Speed differentials on the same bit of track, thus were limited to 75mph with a brief spell of 80mph.
I did wonder if it was a differential issue rather than an outright network wide limit. Salford - Bolton is the only section the 769s would have a chance of exceeding 75 anyway due to lower line speeds and/or close proximity of stations on the rest of the routes they serve.
Regarding your last sentence, I was always under the impression that the 319s/769s are capable of 100mph as that was the maximum speed they ran at when they worked on Thameslink.
Or is it that when using diesel power, they can only go at a maximum of 75mph?
It is said 769s become a little feeble on diesels at around 75 mph, and with a few extra tonnes under each end vehicle, they won't be as nimble as the straight electric class 319.
It is said 769s become a little feeble on diesels at around 75 mph, and with a few extra tonnes under each end vehicle, they won't be as nimble as the straight electric class 319.
That's fairly obvious as they carry about 15 tonnes more weight yet have about 20% less power available. In my experience, it did seem OK getting to 70 and it held it for a few miles on level track where the speed limit was 70/75.
But surely the weight of the diesel equipment is only the same as 200 people, who would have been crush loaded in to each carriage in the Thameslink days. They were still pretty nimble then.
But surely the weight of the diesel equipment is only the same as 200 people, who would have been crush loaded in to each carriage in the Thameslink days. They were still pretty nimble then.
Probably. I remember one of the early postings from 'Clarence Yard' suggesting they had chosen to put seats back in relative to their Thameslink days to help weight distribution.
Probably. I remember one of the early postings from 'Clarence Yard' suggesting they had chosen to put seats back in relative to their Thameslink days to help weight distribution.
Empty no, but packed - probably rarely. Anyway, obviously installing diesels will add much weight and it simply has to be accepted that there is a performance penalty for bi-mode capability.
But surely the weight of the diesel equipment is only the same as 200 people, who would have been crush loaded in to each carriage in the Thameslink days. They were still pretty nimble then.
I made all those points a couple of years ago, however the track standards and expectations of loads on the MML and BML where the 319 worked most of their lives are far higher than the lines that the 769s are destined for, (even the MAN to Bolton route). I think the driver here is the track access charge which NR is making for them and to be honest, the services that they are running are still viable at 75mph.
I think the driver here is the track access charge which NR is making for them and to be honest, the services that they are running are still viable at 75mph.
...and indeed on GWR the relevant line speeds don't exceed 75mph (except for part of the journey between Redhill and Gatwick Airport where the higher linespeed has barely any difference on journey time).
I was talking to a friend of mine today whose brother works at Reading depot. He reports that the 769s are regarded as a disaster there and some doubt whether they will enter service with GWR, with rumoured (and only rumoured) industrial action threatened around the cab design not conforming to modern standards and thus being boycotted by ASLEF members. This may be untrue and I'm more than happy to be corrected.
ASLEF DDC have yet to agree the introduction of the 769 fleet, true, and that is one of the reasons for the delay into service, but that agreement is dependent on GWR implementing various modifications to the cab (increased leg room, upgraded cab air con) that ASLEF DDC requested. Those mods are either in development or are being implemented (e.g. cab air con is being fitted at Eastleigh at the same time as the ASDO system - although some of the units now at Long Marston will need to return to Eastleigh as ASDO was fitted to them prior to the air con fitment being finalised). So to say industrial action has been threatened is probably a bit strong.
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I originally though that which was reinforced by reports that they achieved 92mph on test at Loughborough, but it appears that the additional weight of the gensets and fuel in the driving cars has led NR to limit them to 75mph to which their track access charge is now probably aligned.
On the Western route, 769s can run at 100mph where permitted, but are not currently authorised to run at DMU differential speeds, which means that on the reliefs east of Reading they are pretty much restricted to 60mph (but not on the mains where the linespeed is 125 with no differential). And on the Bourne End branch the speed is mostly 10/DMU50 which means that 769s can only run at 10mph. Needless to say, this is under discussion with Network Rail.
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Rumour or not, I've had the feeling for some time now that just electrifying Reading - Basing, with a low cost electrification scheme for the LTV branches would have been a much quicker solution. Keep a few Turbo's at Reading for the Gatwick's, possibly freed up by sending (if and when they ever work) the 769s to Bristol to work routes such as Severn Beach and Cardiff - Taunton where they can be kept in either Diesel or Diesel and AC mode only.
Electrifying Reading - Basingstoke has actually been briefly discussed by GWR and NR (along with the low level line and spurs east of Reading which are unelectrified despite there being DC and AC either side), although obviously it would be a long time before that actually happens. Meet AC & DC somewhere in the middle and you could run a 769 to Basingstoke without needing to start the engines. You could also run a 387...
Electrifying Reading - Basingstoke has actually been briefly discussed by GWR and NR (along with the low level line and spurs east of Reading which are unelectrified despite there being DC and AC either side), although obviously it would be a long time before that actually happens. Meet AC & DC somewhere in the middle and you could run a 769 to Basingstoke without needing to start the engines. You could also run a 387...
That looks interesting given the SWML/Electric Spine's indefinite delay. Even if there was an unelectrified bit in the middle,at least it would mean that the train wouldn't need to sit there with the engine idling at each end.
ASLEF DDC have yet to agree the introduction of the 769 fleet, true, and that is one of the reasons for the delay into service, but that agreement is dependent on GWR implementing various modifications to the cab (increased leg room, upgraded cab air con) that ASLEF DDC requested. Those mods are either in development or are being implemented (e.g. cab air con is being fitted at Eastleigh at the same time as the ASDO system - although some of the units now at Long Marston will need to return to Eastleigh as ASDO was fitted to them prior to the air con fitment being finalised). So to say industrial action has been threatened is probably a bit strong.
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On the Western route, 769s can run at 100mph where permitted, but are not currently authorised to run at DMU differential speeds, which means that on the reliefs east of Reading they are pretty much restricted to 60mph (but not on the mains where the linespeed is 125 with no differential). And on the Bourne End branch the speed is mostly 10/DMU50 which means that 769s can only run at 10mph. Needless to say, this is under discussion with Network Rail.
== Doublepost prevention - post automatically merged: ==
Electrifying Reading - Basingstoke has actually been briefly discussed by GWR and NR (along with the low level line and spurs east of Reading which are unelectrified despite there being DC and AC either side), although obviously it would be a long time before that actually happens. Meet AC & DC somewhere in the middle and you could run a 769 to Basingstoke without needing to start the engines. You could also run a 387...
Thanks for the response and especially the emboldened point which I completely accept - as I said, it was only rumoured so it's good to have it corrected. Regarding the electrification, I can't imagine the juice rail being permitted to be extended, so presumably 25kV would have to start immediately outside Basingstoke. All pie-in-the-sky, I realise.
ASLEF DDC have yet to agree the introduction of the 769 fleet, true, and that is one of the reasons for the delay into service, but that agreement is dependent on GWR implementing various modifications to the cab (increased leg room, upgraded cab air con) that ASLEF DDC requested. Those mods are either in development or are being implemented (e.g. cab air con is being fitted at Eastleigh at the same time as the ASDO system - although some of the units now at Long Marston will need to return to Eastleigh as ASDO was fitted to them prior to the air con fitment being finalised). So to say industrial action has been threatened is probably a bit strong.
Obviously not privy to any of this but I would have thought Porterbrook and the DfT would have sought inspection and approval from GWR and the DfT to prove the whole class 769 concept was financially viable. There has been millions of pounds invested by Porterbrook in Wabtec's engineering work, but before that there were visits to Wolverton etc etc. I wonder when the cab air con requirement became a necessity and how that modification and fitment was factored into the contract. Ditto the ASDO, ditto that communication gizmo on the front of the cab roof etc etc.
Presumably DfT are underwriting Network Rail's implementation of all the trackside signage relating to bi mode operations of the 769s, in the same way as the class 800/802 operattions.
I just find the whole class 319 into 769 story so amazing.
Long Marston > Wolverton > Loughborough > Burton > Reading > Eastleigh > Reading > Wolverton > Reading. Presume the same work has been done on all nineteen units at some point, but have they all been done at the same locations.
Real-time train running information for 3V11 1100 departure from Gatwick Airport to Reading on 16/02/2022. From Realtime Trains, an independent source of train running info for Great Britain.
www.realtimetrains.co.uk
== Doublepost prevention - post automatically merged: ==
Obviously not privy to any of this but I would have thought Porterbrook and the DfT would have sought inspection and approval from GWR and the DfT to prove the whole class 769 concept was financially viable. There has been millions of pounds invested by Porterbrook in Wabtec's engineering work, but before that there were visits to Wolverton etc etc. I wonder when the cab air con requirement became a necessity and how that modification and fitment was factored into the contract. Ditto the ASDO, ditto that communication gizmo on the front of the cab roof etc etc.
Presumably DfT are underwriting Network Rail's implementation of all the trackside signage relating to bi mode operations of the 769s, in the same way as the class 800/802 operattions.
I just find the whole class 319 into 769 story so amazing.
Long Marston > Wolverton > Loughborough > Burton > Reading > Eastleigh > Reading > Wolverton > Reading. Presume the same work has been done on all nineteen units at some point, but have they all been done at the same locations.
Yes - whatever the internal railway industry details, the fact that users of the North Downs line have been promised these 'new', longer trains for years now is a PR failure at best. I don't know if any passengers on the route have noticed the large four zone signs on every platform (and that some of them are wrong!) but those that have must be wondering what on earth they mean! BR designed a very successful electro-diesel class in the late 1950s, which has survived in main line service to this day, but we can't sling some engines under a unit now! Yes, I know the elements involved are so much more complex now, but still...
Possibly. 769s like 319s before them have two AWS receivers. The AWS magnets on DC electrified lines have a much stronger magnetic field to overcome the electromagnetic interference from the 3rd rail so there is an AWS receiver for DC, and another for AC & diesel. The switch from one to the other should happen as part of the power changeover procedure, but if it doesn't then the train can be running with the wrong receiver active, which can result in lots of AWS irregularities. That's just an educated guess on my part though as to what happened on 939 today.
Meanwhile, 936 failed at Guildford this afternoon with a traction motor fault, could only get as far as Wanborough on the other motor, so headed back to Guildford, and is now sat in disgrace in the sidings awaiting rescue tomorrow.
Possibly. 769s like 319s before them have two AWS receivers. The AWS magnets on DC electrified lines have a much stronger magnetic field to overcome the electromagnetic interference from the 3rd rail so there is an AWS receiver for DC, and another for AC & diesel. The switch from one to the other should happen as part of the power changeover procedure, but if it doesn't then the train can be running with the wrong receiver active, which can result in lots of AWS irregularities. That's just an educated guess on my part though as to what happened on 939 today.
Meanwhile, 936 failed at Guildford this afternoon with a traction motor fault, could only get as far as Wanborough on the other motor, so headed back to Guildford, and is now sat in disgrace in the sidings awaiting rescue tomorrow.
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