Greater Anglia's Stadler Flirt - Class 745 & 755

[Zomboid]

It's too early to be hinting at any cause.

If people were working on equipment at the time that it operated in an unexpected manner then obviously that'll be part of the investigation, as will the way the new rolling stock interacts with the infrastructure.

[phil-b259]

2 hours ago, Zomboid said:

Trains which don't reliably activate track circuits are nothing new, so you'd expect there to be known solutions available.

 

The problem is that the old trains have already been sent on their merry way, leaving GA with nothing. Which is down to the structure of the industry more than anything else.

 

So you would be forgiven for thinking that Stadler should have done some research to make sure the design of their product took into account the lessons of past mistakes!

 

GA / the DdfT can't wiggle out of it either - who was it that came in with the lowest cost fleet replacement bid and who was it who let the franchise accordingly?

[phil-b259]

1 hour ago, iands said:

AIUI, unless the type of controls for the crossing in this particular incident are different, the track circuits for AHB type crossings had to occupy and clear in sequence, including the "exit" TC at the crossing, in order for the crossing to act normally. If a TC occupied/cleared out of sequence, then the crossing "failed" and the barriers stayed down. No doubt in the fullness of time the RAIB investigation and report will inform us all of what did happen, and more importantly, what should have happened. 

 

Down my way the AHBs (1960s and 1980s era installations) only use Treadles for operation - track circuits play zero part in the process! This can mean that if the train is travelling slow enough, the exit / clearance treadle picks between bogies and cause the barriers to rise with the back end of the train still over the crossing.

 

As such it is unwise to assume that the level crossings in Norfolk are triggered / cleared in the manor you state - yes it is a possible configuration that is used in various bits of the country, but NOT everywhere...

[iands]

22 minutes ago, phil-b259 said:

 

Down my way the AHBs (1960s and 1980s era installations) only use Treadles for operation - track circuits play zero part in the process! This can mean that if the train is travelling slow enough, the exit / clearance treadle picks between bogies and cause the barriers to rise with the back end of the train still over the crossing.

 

As such it is unwise to assume that the level crossings in Norfolk are triggered / cleared in the manor you state - yes it is a possible configuration that is used in various bits of the country, but NOT everywhere...

Many thanks for the clarification Phil. I was aware of the treadle operated AHBs (from the 3 sets at Riccall on the former section of ECML prior to the "Selby diversion". I had a vague notion of the TC sequencing from discussions in the office, but I may have misunderstood the type of crossing this method of operation was being applied to (I've not been directly involved with the "S" side of things for over 40 years now, the "T" side being my field, but I do still maintain an interest in all things "infrastructure", even if I misunderstand some of the finer "S" details. 

[Grovenor]

As I remember the '60s designs the treadles supplemented the track circuits to ensure a more precise timing, I never heard of designs where the track circuits played no part. Belt and braces was the aim.

However level crossing predictors are a whole different ball game, first time I've heard of their use in UK although they have been used in the USA for many years. Essentially they measure the rate of change of the impedence between the rails as the train approaches and use that to trigger the warnings at a consistent time irrespective of the speed of the train.

[phil-b259]

26 minutes ago, Grovenor said:

As I remember the '60s designs the treadles supplemented the track circuits to ensure a more precise timing, I never heard of designs where the track circuits played no part.

 

Well you have now!

 

In fact treadle operated automatic crossings are far better in most respects as even with poor railhead contamination or lightweight vehicles, trains will still be detected by the system.

 

There is supposedly a long term project to add the track circuits over the crossing itself (more as a measure to prevent the barriers rising prematurely due to slow moving trains), but due to the current configuration of the track circuits, the need to alter the crossing wiring and the overall shortage of S&T designers / testers in the UK its a low priority one.

Edited December 7, 2019 by phil-b259

[phil-b259]

33 minutes ago, iands said:

I had a vague notion of the TC sequencing from discussions in the office

 

Its no different from Treadle operation in principle  - the treadles must all be activated in the correct sequence (and cleared - the second treadle resets the first, the third resets the second, etc) for the crossing not to fail safe (road lights going, barriers down, failed indication in signal box).

[ruggedpeak]

GA probably hoping one of these new units doesn't run into one of their 90's or Mk3 DVT at low speed and create another inadvertent crashworthiness test..........

[russ p]

Heard today another one disappeared on the cromer branch last Thursday not sure how true it is

The whole line was resignalled by an American company in 2000 I believe axle counters are involved for line occupancy 

[Siggie in the east]

8 hours ago, Titan said:

 

This does not quite match the facts as presented by the RAIB:

 

At about 19:53 hrs on Sunday 24 November 2019, a 4-coach class 755 passenger train, operating the 19:45 Norwich to Sheringham service, was approaching Norwich Road automatic half barrier level crossing, to the north-east of Norwich. The crossing barriers were in the lowered position until the train, travelling at about 45 mph (72 km/h), was about 200 metres from the crossing. The barriers then lifted, the level crossing warning lights went out and cars began to cross the railway. The train driver applied the train’s emergency brake and sounded its warning horn, but the train was unable to stop before reaching the crossing. No road vehicles were struck but a car passed in front of the train around a quarter of a second before the train went over the crossing.

 

So the crossing did activate, but then the barriers lifted and the warning lights went out.  If there were S+T guys working in the relay room at the time, then it may well be a bit early to blame the trains...

My apologies, should have clarified, when I said 'working' In the relay room, i didnt mean working on the signalling equipment. They were just on site when the incident happened. 

[Johann Marsbar]

Stadlers had reappeared on the Norwich-Lowestoft/Yarmouth services by lunchtime today.

Wheelsets were being inspected before the start of each trip though, which added to delays.

[swills]

On ‎06‎/‎12‎/‎2019 at 17:38, beast66606 said:

 

It's slightly more than what you were told Andy - the tracks measure the speed of the train so the barriers are always down for more or less the same time, no matter how fast the train is travelling.

 

We had an S&T guy here the other day explaining how it works, and yes it is a 'predictor' system, and based on occupation and some sort of electrical feedback, (did not really follow what he was saying), operates the AHB's so that be it a 156 / 755 running at line speed, or the Tanks running at a lower speed, the AHB's will be down for roughly the same amount of time, but it seems the 755 must have 'vanished' and the crossing thought, OK train gone :-)

Cannot see a quick fix for the 755s, and something needs to be done by Monday, maybe restrict the 755s to Yarmouth & Lowestoft, and use the 156s and the 170 on Cambridge & Ipswich trains, with Felixstowe and Sudbury taking the 'no train' hit ?   also seems to be something odd going on with the actual wheelsets too

[swills]

12 hours ago, Suzie said:

Is that not why axle counters were invented?

 

No, not really, they are cheaper than proper track circuits, seems the AHB system on the Cromer, might be unique to that line ?

All the other AHB's around here, are worked by traditional track circuit, backed up by treadles, which made life so much easier when we have (what are now rare) OTM's that cannot be relied upon to activate track circuits.

There certainly seems a few issues surrounding the 755s, another problem being the pantograph when going OHL to Diesel.

[uax6]

The Basils could be used Camb-Norwich, as the crossings that way have treadles afaiaa, and there has been no issues so far (they aren't cleared for working off the OHLE Ely-Cambs yet, so there's no issues with the pans to worry about, and the ETN is mainly axle-counters with tracks/treadles for the crossings.

 

Maybe a couple of wire-linked wire brushes on the guard irons would help?

 

Andy G

[Johann Marsbar]

6 hours ago, uax6 said:

The Basils could be used Camb-Norwich, as the crossings that way have treadles afaiaa, and there has been no issues so far (they aren't cleared for working off the OHLE Ely-Cambs yet, so there's no issues with the pans to worry about, and the ETN is mainly axle-counters with tracks/treadles for the crossings.

 

Maybe a couple of wire-linked wire brushes on the guard irons would help?

 

Andy G

 

Basils brushes....???

 

Boom, Boom!

[corneliuslundie]

Any modeller could have told them about the need to keep the wheels clean!!

Hat, coat, wellies (well, this is Wales)

Jonathan

[On the block Allan]

On the Greater Anglia website at 08.00 this morning (Sunday) 77 trains were shown as cancelled for the best part of the day and not one cancellation included the place Norwich, makes one wonder why?

 

Al.

[russ p]

Their website is still saying signalling problems which is wrong as it make people think the east Midlands services will be delayed too.

Its about time they told the truth 

[The Stationmaster]

On 07/12/2019 at 10:33, iands said:

AIUI, unless the type of controls for the crossing in this particular incident are different, the track circuits for AHB type crossings had to occupy and clear in sequence, including the "exit" TC at the crossing, in order for the crossing to act normally. If a TC occupied/cleared out of sequence, then the crossing "failed" and the barriers stayed down. No doubt in the fullness of time the RAIB investigation and report will inform us all of what did happen, and more importantly, what should have happened. 

Yes, plus this would appear to be a predictor type crossing (a bad design idea in any event in my view) which might introduce other factors.  Automatic level crossings - of any kind - which rely solely on track circuit actuation have long presented problems because they are totally reliant on track circuits working correctly.

 

There would appear to me to be a number of issues here, i.e. -

1.  Track circuit actuation problems (which should have emerged long before now I would have thought, these trains have been running around for quite a while now over track circuited lines),  including

1b. Potential wheel contamination preventing the train from correctly actuating track circuits.

2.   The use of predictor equipped automatic level crossings where there is no train actuated proof that a train has passed over the crossing before it reopens to road traffic.

3.  The presence of 'S&T' staff working in the location where the controls are sited (it wouldn't be the first time ...   ...).

4.  Any specification or design stipulations (e.g. unsprung weight) which might affect teh train's actuation of track circuits and the level of testing of any electronic/magnetic emissions beg fore giving authority to run. 

 

A much wider issue is the whole question of instant cascade/scrapping programmes before new rolling stock is fully settled into everyday passenger service.   But overall, as 'iands' has already pointed out none of this should be novel and a proper regime of specification and design coupled with comprehensive testing and reference to known potential and past problems should have taken all of that into account.  The ISA process - if correctly applied - should also have picked it up in today's situation however that then raises questions about that past experience situation. (as I found out earlier this century when carrying out ISA work and raised matters in my past experience which the design and test people were not aware of).

[woodenhead]

So what has changed recently - it's RHTT season?

[Johann Marsbar]

1 hour ago, On the block Allan said:

On the Greater Anglia website at 08.00 this morning (Sunday) 77 trains were shown as cancelled for the best part of the day and not one cancellation included the place Norwich, makes one wonder why?

 

Al.

That generally seemed to be the case yesterday (altough one Cromer service at 12.45 was a bus), though if they are having to send out staff to clean the wheels before each run, the fact that they are likely to come from Crown Point (or should that be Fawlty Towers??) means that it is easier to do from Norwich. Certainly I spotted the same person on wheel cleaning at Norwich who was then at Lowestoft later, so one assumes he was travelling on the units.

City are at home today as well, apparently.........

 

 

[russ p]

19 minutes ago, Johann Marsbar said:

That generally seemed to be the case yesterday (altough one Cromer service at 12.45 was a bus), though if they are having to send out staff to clean the wheels before each run, the fact that they are likely to come from Crown Point (or should that be Fawlty Towers??) means that it is easier to do from Norwich. Certainly I spotted the same person on wheel cleaning at Norwich who was then at Lowestoft later, so one assumes he was travelling on the units.

City are at home today as well, apparently.........

 

 

 

 

Maybe they should put a 37 on the front,  that would actually get round any  perceived problems but can't imagine GAs publicity department would like their new trains needing a 60 year old design to make them safe to operate! 

[wombatofludham]

Seems a little odd that they used "speed predicting" track circuit level crossing technology on the Cromer branch when, at least north of North Walsham, pretty much all the trains will be travelling at much the same speed given the slower freights terminate at North Walsham, and even south of the oil terminal towards Norwich, don't run at a frequency which would justify such a complication for traffic reasons.  I worked at Norfolk County Council in the Passenger Transport Unit at the time the line was resignalled and from what I heard from railway sources at the time I suspect it may have been a case of Railtrack trying to stir up the way it procured such schemes as was their want.

It's a shame to see what when running are passenger friendly and popular trains undermining the immense work the two community rail partnerships have achieved in Norfolk in regenerating the rural lines.  I hope they can get them sorted quickly as they have the potential to really transform the network.

[On the block Allan]

This morning, Monday, 113 trains are shown as cancelled for the rest of the day on the Greater Anglia website at 05.00, of those trains, 111 serve stations in Suffolk and only 6 serve Norwich!

 

Al.

[beast66606]

Norwich / Cambridge is today a Norwich / Ely.

Ipswich / Felixstowe - cancelled

Ipswich / Cambridge - 2 hour

Ipswich / Peterborough - cancelled

Norwich / Sheringham (Cromer) - delays

 

It makes sense to keep the Norwich / Cambridge service running as longer distance travellers from Suffolk can at least travel to Norwich and then get a train to Ely for onward travel. Given their difficulties this is prbably the best option to at least run a service of sorts, obviously Bury suffers but at least has a 2 hourly service.