Failed Unit
Established Member
Be interesting to see how the change over failures compare to the other frequenct ones. The 313 at old street. I am sure each set does more per day because of the shorter diagram. However 313s are simple beasts.
-
Our booking engine at tickets.railforums.co.uk (powered by TrainSplit) helps support the running of the forum with every ticket purchase! Find out more and ask any questions/give us feedback in this thread!
Thameslink/ Class 700 Progress
- Thread starter fgwrich
- Start date
- Status
Sponsor Post - registered members do not see these adverts; click here to register, or click here to log in
R
RailUK Forums
The make up time is shifted from the dwells in the core to circle / diamond time (pathing / performance allowance) just before the core. Journey times remain much the same, and it has the added benefit of a lot more trains arriving RT into the core rather than late in (and possibly PPM failures) but on time out.
Ah, but the 378s don't have to stop in a very specific location for the changeover. I should imagine changeover problems will reduce when the ATO is switched on.
Sorry to pick this up again; of the Sutton trains yesterday morning none were delayed by dwells. The delays were reaction to a train immediately in front, and generally they all made back time.
On another matter, I would be interested to here from ComUtoR and other drivers of their experience of driving 700s in autumn conditions.
The train I caught this morning (2V19), when it was formed of 319s, would struggle in the conditions we encountered this morning - plenty of leaves around, wet rails and light rain. There would be much slipping, and very careful braking. It would not be unusual to lose 7-8 minutes between Luton and St Pancras.
This morning we were on time, no slipping, and braking as normal. I appreciate it is early in Autumn, but are the trains more sure-footed (sure-wheeled?) Monday will be the big test I guess.
The train I caught this morning (2V19), when it was formed of 319s, would struggle in the conditions we encountered this morning - plenty of leaves around, wet rails and light rain. There would be much slipping, and very careful braking. It would not be unusual to lose 7-8 minutes between Luton and St Pancras.
This morning we were on time, no slipping, and braking as normal. I appreciate it is early in Autumn, but are the trains more sure-footed (sure-wheeled?) Monday will be the big test I guess.
westcoaster
Established Member
They are much better to drive in the autumn, never encountered any issues last year. The sanding system seems more adaptive than on previous stock. Another thing to remember when comparing a 319 to a 700 is the whole braking system. On a 319 it was just disk brakes to get stopped with, on a 700 you have got disk brakes, rheostatic braking plus brake blocks (tread brakes). Also the tread brakes clean the powered wheels.
Failed Unit
Established Member
Fair enough. Without being in that cab you never know if you are getting held at red.
Good the Sutton’s catch up considering the number of flat junctions they encounter.
I agree with Westcoaster. So far I have found them to be better but certainly because the brake system is much more advanced. I also agree that the sander is in overdrive and it sands at the slightest hint of a slip.
They outperform a 319 in the rain by a country mile and I haven't suffered in the rain yet.
They are slipping that's for sure and potentially slipping more than a 319 did. What I have noticed is that it deals with it much better. The computer is adjusting the brake and the power constantly and the unit is adapting pretty quickly. They haven't really been tested yet. The leaves are still up and the slip is light at the moment.
I also didn't have much problem with a 319 either. Autumn driving is where a Driver earns their crust. A lot can be put down to the Driver and the skill they have at controlling their unit. I would add that this is the first year that they are going through the leaffall so we are not doubt all a little more defensive than usual and making personal assessments to how they will perform.
Without a doubt a 700 is a better train. But it should be. It's like comparing a Tesla to an Austin Allegro :/
They outperform a 319 in the rain by a country mile and I haven't suffered in the rain yet.
They are slipping that's for sure and potentially slipping more than a 319 did. What I have noticed is that it deals with it much better. The computer is adjusting the brake and the power constantly and the unit is adapting pretty quickly. They haven't really been tested yet. The leaves are still up and the slip is light at the moment.
I also didn't have much problem with a 319 either. Autumn driving is where a Driver earns their crust. A lot can be put down to the Driver and the skill they have at controlling their unit. I would add that this is the first year that they are going through the leaffall so we are not doubt all a little more defensive than usual and making personal assessments to how they will perform.
Without a doubt a 700 is a better train. But it should be. It's like comparing a Tesla to an Austin Allegro :/
westcoaster
Established Member
This time of the year is 60/60. 60% power and 60%brake. Can tell when a 700 loses grip while accelerating you hear that awful shrill.
I've been watching the power/brake gauge. You stick it in 60% and the bar begins to fluctuate. Its like watching the needle bounce in other stock. I'm actually quite glad that there is still the traditional indications of slip. The shrill is weird and I can't figure if its the wheels on the rails or something else. Either way its a very good indication.
I've missed 1 RLU mark so far and that was because the brake suddenly dropped out about a foot from the RLU mark. Other than that, its been pretty good and I can semi predict what's gonna happen when I brake.
I've missed 1 RLU mark so far and that was because the brake suddenly dropped out about a foot from the RLU mark. Other than that, its been pretty good and I can semi predict what's gonna happen when I brake.
JohnRegular
Member
- Joined
- 12 Dec 2016
- Messages
- 253
How practical would it be to extend OLE south (or third rail north) of the core? Not far, just far enough for any trains that have sat down on changeover to be overtaken and not cock up the entire service.
I imagine the 700s will only get more reliable over time, but it doesn't seem like a logical long term solution to have a voltage changeover occur in the most crucial part of the thameslink network.
Last edited:
swt_passenger
Veteran Member
- Joined
- 7 Apr 2010
- Messages
- 31,378
The dual voltage section now covers two stations and certain crossovers either near or between them. This was already done specifically to give more options for recovery from failed changeovers. Prior to the works all changeovers had to happen at Farringdon.
Unless it is expected to continue to operate many DC only trains amongst the 24 tph , would it not be practical to extend the ac up to Blackfriars platforms on the through lines only. That would avoid needing the very high switched DC power up the 1:29 from City Thameslink southbound (worst case: one 700 propelling another failed one up the gradient). I suppose there may not be enough clearance in Smithfield sidings OLE, but in such a restricted access location, even with the current TSI rules, it may be possible to squeeze the conductors in.
bengley
Established Member
- Joined
- 18 May 2008
- Messages
- 1,842
For anyone interested, the ETCS in the core will be commissioned from tomorrow morning, though no drivers have yet been trained on it so the normal signalling will still be the norm for the time being.
tsr
Established Member
You appear to have overlooked my mention of London Overground. We mustn't forget they see a perfectly reasonable rate of changeovers with, it would seem, a very low rate of failure.
Having looked into it in more detail with regards to the Electrostar incident which I mentioned, the units (plural) were considerably over 3 years old and it does appear to be quite an unusual fault. I suggest some components on the units in question could now be coming out of the other side of the bathtub curve, if you see what I mean.
Still perhaps a bit of a skewed comparison, I guess, though.
Interesting - and I am glad to hear there is some leeway there (including diamond allowances, which I have a sneaking suspicion have been overlooked in more than a few diagrams which get bunged in my direction - all flagged up of course, if I can see a definite requirement).
I assume there is enough space on the approaches to London Bridge / Elephant & Castle / etc. for trains to wait if they are not yet due into the Core and they have to await a late running service - which could be one or two stops away, yet said late service would make up the delay within its allowances, and therefore cannot be regulated behind the train which is awaiting a path.
It's a good point, but there have been a few issues on Thameslink lately where the driver has gone for a "second go" with changeover at the next station, having stopped in the right place the second time, and then the train has thrown a wobbly because it went wrong on the original attempt. At the moment this seems to cause delays of around 10 minutes.
Would the metallic roof structure at Blackfriars cope with OHLE? I have heard rumours that it would, but can't be sure it would fit. If it did, perhaps it would be via an overhead conductor bar.
Last edited:
That was intentional as your post #8787 refers to just classes 700 & 377. As Bald Rick has since pointed out, the 378s do not need to stop with the same precision and of course, maturity of the deisgn and the likely age of individual units should ensure that they are well into the low failure phase of their service life.
It wasn't meant to be a serious critique of the relative reliability of both classes, but much of the criticism of class 700s here seems to be based on the actual number of failures without recognising the already very high number of relatively immature vehicles (in reliability terms) in full service.
Well there's already been one attempt to collect power via a pantograph under the Blackfriars roof.
So in respect of issues with extending the ac south, would there be any other difficulties, 0?
tsr
Established Member
Well there's already been one attempt to collect power via a pantograph under the Blackfriars roof.
Well, thinking about it in more detail, one does need to consider how to prevent the AC and DC supplies interfering with both each other and the signalling equipment, which might, I suppose, need different equipment on Blackfriars Bridge compared to other locations where it is tried so far. With the incline also requiring greater power draw, I wonder if that could also impact on this.
I also suppose three changeover attempts, then a failure being declared, might cause more disruption and knock-on delays than just two attempts. In a perfect world it shouldn't be too much longer, but...
Well there's already been one attempt to collect power via a pantograph under the Blackfriars roof.
More than one attempt!
The most complex part of the core, and therefore also the highest risk to reliability, is the earthing arrangements for the dual voltage section. Not to put too fine a point on it, it's a nightmare. Just in the last two years, it has caused three major signalling failures. It also causes a significant amount of extra maintenance. There are a handful of block joints in particular that need renewing Avery six months.
Extending the AC south brings those problems to the main lines out of Charing Cross. Taking the DC north brings the problems to the main lines out of St Pancras and Kings X.
bramling
Veteran Member
How wonderful. It’s reassuring to know that such a wide part of the south-east’s commuter railway is in the hands of a ‘nightmare’ with so many associated ‘problems’.
D365
Veteran Member
- Joined
- 29 Jun 2012
- Messages
- 11,448
Well what do you suggest? Want me to look into throwing some batteries under the 700s for you?
bramling
Veteran Member
Would that not unacceptably increase the weight of the train? Given that we were told tables would be unacceptably heavy...
As to what I would suggest, I think you know what I would suggest...
It's always been like that, and the changeover happens in the best place.
swt_passenger
Veteran Member
- Joined
- 7 Apr 2010
- Messages
- 31,378
Indeed, and it shouldn't really come as a surprise, given the frequency with which it has been discussed in Thameslink and 700 related threads over the last few years.
Alteran Ancient
Member
I travelled southbound though City Thameslink last night without stopping, as the station had been closed for the night. When the station is closed, do northbound trains still stop to switch over to AC, or do they continue on DC and swap over once at Farringdon?
swt_passenger
Veteran Member
- Joined
- 7 Apr 2010
- Messages
- 31,378
I think so, Opentraintimes shows that they still stop northbound for "operational reasons", no public times are shown.
Example here: https://www.opentraintimes.com/schedule/G48932/2017-10-21
Southbound trains are all shown as PASS.
bengley
Established Member
- Joined
- 18 May 2008
- Messages
- 1,842
Correct, we stop at City on the Northbound to change power supplies even when the station is closed.
On the south it's done at Farringdon.
Perhaps I haven't been paying attention but I see the 700s now have a recommendation to 'Please make sure you have all your belongings, and take care as you leave the train' when stopping - except I'm on one which is saying nothing else as we progress towards London. I assume it has frozen, or perhaps because the train is delayed they changed the stopping pattern...
...because on the way into London this morning during disruption, everything worked fine until we had an additional stop inserted at Hendon. From that point on, the system stopped giving the stopping pattern or any audible announcements and when there was a driver change later on, we got manual announcements. This must be frustrating for the driver whatever the case.
Meanwhile, no loading/toilet/TfL information and plenty of people boarding at East Croydon unsure of where the train was going and where it was stopping, having to ask platform staff who were of course trying to get the delayed service moving! No announcements from the driver this time.
I have to say this is pretty poor and only leads to trains losing more time unnecessarily.
https://photos.app.goo.gl/3ngCnxT8AwRlDaL22
...because on the way into London this morning during disruption, everything worked fine until we had an additional stop inserted at Hendon. From that point on, the system stopped giving the stopping pattern or any audible announcements and when there was a driver change later on, we got manual announcements. This must be frustrating for the driver whatever the case.
Meanwhile, no loading/toilet/TfL information and plenty of people boarding at East Croydon unsure of where the train was going and where it was stopping, having to ask platform staff who were of course trying to get the delayed service moving! No announcements from the driver this time.
I have to say this is pretty poor and only leads to trains losing more time unnecessarily.
https://photos.app.goo.gl/3ngCnxT8AwRlDaL22
The ones suggested in this posting on the 700s to GN thread
https://www.railforums.co.uk/threads/great-northern-class-700-diagrams.155704/#post-3175401
- Status