Greater Anglia's Stadler Flirt - Class 745 & 755

[beast66606]

1 minute ago, Siggie in the east said:

Not sure of the set number but 1 is being stored on the MNR, they posted a video of it on the FB page being delivered by 37600 about a month ago

 

Agreed but 321s had already been working some of the diagrams, and at least 3 of the coaches are back at Crown Point already.  I'm not sure there is a shortage of stock for the main line services (barring failures of stock / CPt)  so the stored coaches are not affecting services so they have not been "got rid of too early" as TallTim was saying ^ ^.

[Siggie in the east]

5Q46 Ips-Peterboro 755407 test trip to Posh and back, currently 59 late.

[Talltim]

1 hour ago, beast66606 said:

 

Which 90 sets have they got rid of ?

I’m sure I read on this thread that some were stored, but I’ve been back pages and pages and I can’t find it. I’ll take it back

edit, ah I see I wasn’t dreaming it!

Edited December 19, 2019 by Talltim

[Bad79]

Oi railway way it is ur 755 oh sorry ga 755, as ur nothing to do with them.I am told old   stock touch rail with50p new755 5p. I hearing all over nothing t do with Cromer line

 

[admiles]

11 hours ago, Talltim said:

I’m sure I read on this thread that some were stored, but I’ve been back pages and pages and I can’t find it. I’ll take it back

edit, ah I see I wasn’t dreaming it!

 

The only Mk3 coaches to go to the MNR were spare vehicles to free up a bit of space at Crown Point. No complete rake has been stored yet.

 

321 units have been working some diagrams for a while now, something to do with re-jigging the timetable slightly to allow the much heralded "Norwich in 90" service.

Edited December 19, 2019 by admiles

[Christopher125]

16 hours ago, Zomboid said:

I'd love to know the thinking behind putting sanders on unmotored wheels. Sounds like rookie mistake to me, though it's not something I know much about. There could be a good reason for it being like that...

 

This Rail Engineer article appears to suggest sanding the third axle is standard (if not required?) practice, presumably so sand doesn't interfere with the front bogie triggering track circuits.

 

It might be unusual for axle 3 to be so far from the next set of driven wheels but braking performance surely takes priority, so it's as far forward as possible.

 

I think that all makes sense?

Edited December 19, 2019 by Christopher125

[The Stationmaster]

18 hours ago, Siggie in the east said:

Last bit of info from me for now.

 

As a compromise from NR, over the weekend, treadles are being fitted to crossings on the sheringham/cromer branches to help with train detection so that services to Sheringham can begin to run again safely and reliably.

This is NOT an admission of guilt on NRs part but a way of compromise and working together with GA to get the passengers the train service they deserve

 

Thanks

Sounds more like a move to commonsense long adopted elsewhere to be honest.  Plenty of BR discovered a long time ago that to ensure reliable automatic level crossing operation treadles were essential as they generally tend to be far more reliable than track circuits in such applications and i was rather surprised to hear that these crossings hadn't got them.  And to hear that predictor equipment was still in use (another route to potential problems) was rather worrying.

 

As this thread degenerated into a version of mini-Norway which a major troll presence I haven't bothered to read what I have missed over the past couple of days but as I pointed out a while back there are various scenarios for what might have been going on and for some reason (the TCA position??) there appeared to be some sort of interface problem between these trains and the signalling system which could be down to either or both and might include a speciication/design problem with the trains.

 

When we hear the full explanation of what went wrong (or didn't go right) and why we - as bystanders - will be in a possible position to judge. Until we know the full facts all we do know is that, for whatever reason. a problem has emerged during everyday operation which seemingly did not emerge during testing/mileage accumulation.  The fact that such a problem has emerged is hardly a novelty and some of us, during our railway careers, have seen it all before.

 

As for somebody a few pages back implying that pan collision on one of these trains meant there was something wrong with them I would suggest that could well be a nonsense.  Numerous types of train etc running on UK metals have over a good many years suffered from pan collisions of varying levels of severity with damage to train or infrastructure or both.  The first question then is why it occurred and what mitigations were in place to either prevent such a collision or mtigate its effects?  And don't forget that in many cases pan collisaions are down to human shortcomings rather than anything else - and they can happen on all sorts of trains.

[richardw1970]

37 minutes ago, Christopher125 said:

This Rail Engineer article appears to suggest sanding the third axle is standard (if not required?) practice, presumably so sand doesn't interfere with the front bogie triggering track circuits.

I suspect this is mainly due to that being the first driven axle on many units, the exceptions in my experience are the 14x and 153 which do sand the leading axle due to the limited number of axles available.

[phil-b259]

19 hours ago, Siggie in the east said:

Last bit of info from me for now.

 

As a compromise from NR, over the weekend, treadles are being fitted to crossings on the sheringham/cromer branches to help with train detection so that services to Sheringham can begin to run again safely and reliably.

This is NOT an admission of guilt on NRs part but a way of compromise and working together with GA to get the passengers the train service they deserve

 

Thanks

 

From a technical perspective I wonder how they are doing it. Treadles by their nature are monetary devices and while one cut through a track circuit may drop the track, it won't keep it occupied and I though that was the whole point of the original near miss incident (i.e. track goes clear barriers go up)

 

Down my way the treadle operated crossings are worked on the basis that the rely fed by treadle A will only be re-energised by the operation of treadle B, which then requires the operation of treadle C to re-energise it, etc. This requires the treadle circuits to be fed back to the barrier controls via lineside cables and the appropriate relays + wiring present at the crossing

 

Thus if the level crossings are designed to work on track circuits then treadles aren't in themselves a lot of use and there is no easy way to add them retrospectively.

[Christopher125]

12 minutes ago, richardw1970 said:

I suspect this is mainly due to that being the first driven axle on many units, the exceptions in my experience are the 14x and 153 which do sand the leading axle due to the limited number of axles available.

 

That would surprise me - it isn't the first driven axle on the 387s mentioned in the article and I can think of many other classes where that isn't the case, in one direction or both.

Edited December 19, 2019 by Christopher125

[richardw1970]

32 minutes ago, Christopher125 said:

That would surprise me - it isn't the first driven axle on the 387s mentioned in the article and I can think of many other classes where that isn't the case, in one direction or both.

I don't know, my comment was based on diesel units where all except the two I mentioned have been sanded on 3rd axle which is the first powered one on them. I have no first hand knowledge of electric units and their powered wheel/sanding arrangements so cannot comment on them with any authority as we don't get much electrickery oop north. I should have been clearer on my original comment, sorry.

[Covkid]

1 hour ago, Christopher125 said:

 

This Rail Engineer article appears to suggest sanding the third axle is standard (if not required?) practice, presumably so sand doesn't interfere with the front bogie triggering track circuits.

 

It might be unusual for axle 3 to be so far from the next set of driven wheels but braking performance surely takes priority, so it's as far forward as possible.

 

I think that all makes sense?

 

Yes but.... If the powered axles on a 755/4 are 1 & 2, and 11 & 12 there isn't a great deal of point in sanding after the powered axles in my view, apart from possibly axle 10 dropping sand for the rear two axles 11 & 12 - if it works in that direction 

[phil-b259]

1 hour ago, Covkid said:

 

Yes but.... If the powered axles on a 755/4 are 1 & 2, and 11 & 12 there isn't a great deal of point in sanding after the powered axles in my view, apart from possibly axle 10 dropping sand for the rear two axles 11 & 12 - if it works in that direction 

 

But brakes are not just fitted to axles 1,2, 11 & 12 are they?

 

While its tempting to think about sand in terms of acceleration - the PRIMARY reason for providing is to help trains brake - not to make them accelerate. A few years ago there was a nasty runaway involving an Electrostar on the Hastings line which couldn't stop for miles and sailed through at least one level crossing with its barriers up primarily because it had empty sand boxes!

 

In that context having them as close to the front of the train as possible seems a very logical approach regardless of where the traction motors are.

[Classsix T]

Everyday is a school day. It's never occurred to me that sand might be used as an aid to speed retardation, I'd always assumed it's sole purpose was as an adhesion aid to acceleration, specifically in wet rail head conditions.

 

It now makes sense that the sanders on 321s aren't directly feeding to the motor carriage, thanx Phil. 

 

C6T. 

[richardw1970]

36 minutes ago, Classsix T said:

Everyday is a school day. It's never occurred to me that sand might be used as an aid to speed retardation, I'd always assumed it's sole purpose was as an adhesion aid to acceleration, specifically in wet rail head conditions.

A lot of us drivers are reluctant to use sand for acceleration to keep it in reserve for stopping as we have no way to tell how much sand is left on a lot of units. Some modern units actually inhibit traction sanding once the sand level drops to a certain point.

[phil-b259]

41 minutes ago, Classsix T said:

Everyday is a school day. It's never occurred to me that sand might be used as an aid to speed retardation, I'd always assumed it's sole purpose was as an adhesion aid to acceleration, specifically in wet rail head conditions.

 

It now makes sense that the sanders on 321s aren't directly feeding to the motor carriage, thanx Phil. 

 

C6T. 

 

RAIB report of the incident I refereed to above https://www.gov.uk/raib-reports/station-overrun-incident-at-stonegate-east-sussex

[russ p]

Years ago its was frowned upon for some reason  to use sand to retard a slide

I was used especially when loose shunting heavy rakes of wagons with a 350 

Or with class 9s in poor rail conditions. 

We were taught to  pulse the sand to help clear blockages and save sand and air

[beast66606]

Eccles Road

19 December 2019

755419 on 1K79, 13:27, Norwich - Cambridge (14:48) - vice Stansted Airport (15:31)

 

The unit got as far as Ely but when the driver tried to raise the pantograph he couldn't, then the diesel engine would not restart (eventually limped to Cambridge and taken out of service) - oops Scotties.

Edited December 19, 2019 by beast66606

[Covkid]

1 hour ago, beast66606 said:

Eccles Road

19 December 2019

755419 on 1K79, 13:27, Norwich - Cambridge (14:48) - vice Stansted Airport (15:31)

 

The unit got as far as Ely but when the driver tried to raise the pantograph he couldn't, then the diesel engine would not restart (eventually limped to Cambridge and taken out of service) - oops Scotties.

 

That is interesting. I believe the 755/3s have two diesel engines, and the 755/4s four.  I guess there is a lot of electronickery to join the control and output of the engines to power the trains  

[black and decker boy]

Rumour that 411 has joined in the work to rule and is refusing to move too?

[rodent279]

3 hours ago, russ p said:

Years ago its was frowned upon for some reason  to use sand to retard a slide

Presumably because the sand acted as a good abrasive, especially on a greasy rail, and accelerated the formation of wheel flats-can anyone confirm?

[russ p]

5 minutes ago, rodent279 said:

Presumably because the sand acted as a good abrasive, especially on a greasy rail, and accelerated the formation of wheel flats-can anyone confirm?

 

Quite possibly,  but if you are going to hit something better damage the tyres than smash the loco up.

When rails are very contaminated you can touch the brake and the train will slide but as the contamination acts as a very good lubricant little if any damage occurs to the tyres 

[Christopher125]

6 hours ago, Classsix T said:

Everyday is a school day. It's never occurred to me that sand might be used as an aid to speed retardation, I'd always assumed it's sole purpose was as an adhesion aid to acceleration, specifically in wet rail head conditions.

 

Interestingly this is being developed further, with Variable Rate Sanding recently trialled on the Redditch branch whose results are described in the Rail Engineer article below:

 

'A little sand in the right place works wonders'

 

 

Quote

To illustrate the effect of the enhanced sanding, a step 3 brake with no sand only managed to reduce speed from 55 miles/hour to 40 miles/hour by the end of the paper tape (a speed reduction of 15 miles/hour over the 750 metres travelled).

 

Once the enhanced sanders were activated for a repeat test, the brake application was so successful that the brakes had to be released early because there was barely enough momentum left to coast to the end of the paper tape so that the pantograph could be raised again. Your author was in conversation with Parvaiz Elahi, the ASLEF health and safety representative, during the step 3 test with sand and we were both suitably impressed.

 

Edited December 20, 2019 by Christopher125

[david.hill64]

3 hours ago, rodent279 said:

Presumably because the sand acted as a good abrasive, especially on a greasy rail, and accelerated the formation of wheel flats-can anyone confirm?

Actually the reverse. Sand improves adhesion which allows the braking force to be transmitted through the contact patch without causing the wheels to slide. 
Wheelflats are caused by a locked wheel leaving an area of low adhesion and entering one of normal adhesion. The sliding friction at the interface then causes a metallurgical transformation of the steel in the wheel. The resultant compound, martensite, is hard brittle and cracked. It then spalls from the wheel leaving a depression that becomes a flat under the rolling action of the wheel. 
It is perfectly possible to have a flat on only one wheel of an axle if only one rail is heavily contaminated but flatting both is more likely. 

[Titan]

A demonstration of the effectiveness of sanding stopping a sliding train on a 1:16 down hill grade:

 

https://youtu.be/mgfzdvkcCao?t=405