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Predictor Level Crossing protection

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  #1  
Old 10th December 2019, 05:41
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aussiesteve aussiesteve is offline
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Predictor Level Crossing protection

A bit of a scare for both the train hogger and traffic.
https://www.gov.uk/government/news/n...level-crossing
I am NOT a fan of predictor style level crossing protection.
Such things were introduced here back in the late 1990s.
Motorists complained about the waiting time at protected level crossings for freight trains.
The advance trip circuit needing to be out far enough to encompass the higher speed of the Rocket (XPT).
But, then a slow slogging freighter would take much longer to reach the crossing.
Hence the predictors to alter the timing of the protection circuits due to actual train speed when tripping the advance circuit.
One such level crossing was on a steep hill climbing out of a dip.
Prior to the predictor, on freighters we would power up over the first hill and then let it run (up to max train and track speed) in the dip.
This would assist the train being able to climb over the next hill on which the level crossing was.
BUT, after the predictor went in, it became VERBOTEN to increase trains speed after tripping the advance circuit.
SO, we had to actually put the brakes ON to maintain the slow speed.
Then power up and struggle over the hill with the level crossing.
The Rocket by contrast able to hit 160 kph.
Steve.


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Old 12th December 2019, 12:22
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Beeyar Wunby Beeyar Wunby is offline  
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Yo Steve. Interesting spot.

Grrrr, all this messing about with crossings just because road users are so impatient.

Conventional (as in in not messed-about with) AHBs have a treadle operated by the flange on the wheel of the approaching train. This operates a series of timers. IIRC the barriers should be down 7 seconds before the train arrives at the crossing......provided that the train is travelling at linespeed.

The sequence seen by a motorist is;
1) The yellow lights flash as a warning
2) The red wigwags flash alternately and the sirens sound. Motorists must stop their vehicle before the road markings
4) The barriers drop, whilst the wigwags and sirens continue.
5) Once the train(s) have passed, the wigwags & sirens stop and the barriers raise.

You may recall that in the Summer I posted a little tale about running for 9 miles along the Single Line at 20mph instead of 90. As you can see, the barriers would have been down a very long time before I arrived at the crossing. Fortunately it's mostly country folk round here, and they like to live their lives a little slower, bless 'em.

The Safety Police's fear is that motorists will get so irate that they swerve round the barriers - They're half-barriers remember.

In my humble opinion, Nitwit Rule would do better to spend the money on threatening signs and video cameras, rather than frigging with the timing of the barriers.

If Wunby ruled the world (and it's just as well he doesn't) anybody who jumps the crossing has deliberately risked the lives of train passengers and should have a spell in the 'Big House'.

Just my 2 cents. Have a nice day
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Old 12th December 2019, 20:52
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In Rhodesia when I was a fireman, all traffic had to stop at any level crossing whether there was a train coming or not. I have known the police to sit near a crossing and watch for a vehicle to cross without stopping, then book the driver. Bare in mind, like Aus. some crossings were way out in the bush, miles from anywhere and were just a train crossing sign and a hump of earth for a crossing. Shows how times have changed.
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Old 12th December 2019, 21:13
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Quote:
Originally Posted by Beeyar Wunby View Post
Yo Steve. Interesting spot.

Grrrr, all this messing about with crossings just because road users are so impatient.

Conventional (as in in not messed-about with) AHBs have a treadle operated by the flange on the wheel of the approaching train. This operates a series of timers. IIRC the barriers should be down 7 seconds before the train arrives at the crossing......provided that the train is travelling at linespeed.

The sequence seen by a motorist is;
1) The yellow lights flash as a warning
2) The red wigwags flash alternately and the sirens sound. Motorists must stop their vehicle before the road markings
4) The barriers drop, whilst the wigwags and sirens continue.
5) Once the train(s) have passed, the wigwags & sirens stop and the barriers raise.

You may recall that in the Summer I posted a little tale about running for 9 miles along the Single Line at 20mph instead of 90. As you can see, the barriers would have been down a very long time before I arrived at the crossing. Fortunately it's mostly country folk round here, and they like to live their lives a little slower, bless 'em.

The Safety Police's fear is that motorists will get so irate that they swerve round the barriers - They're half-barriers remember.

In my humble opinion, Nitwit Rule would do better to spend the money on threatening signs and video cameras, rather than frigging with the timing of the barriers.

If Wunby ruled the world (and it's just as well he doesn't) anybody who jumps the crossing has deliberately risked the lives of train passengers and should have a spell in the 'Big House'.

Just my 2 cents. Have a nice day
Is it just a cost saving that we have mostly half-barrier crossings - wouldn't it be safer to have full barriers?

Tony
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Old 13th December 2019, 02:56
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I don't think that double barrier booms would totally solve the drama.
I have seen idiots attempting to barge their way through.
The full width booms in Nipponland didn't save the truckie a couple of months ago.
He got stranded inside across the tracks when the booms dropped.
Took a wrong turn and then a train attacked dropping the booms preventing his being able to GET OUT.
Kaboom when the truck was hit at 120 kph.
Mind you, they is blaming the train hogger for this due to the level crossing detection system.
It supposedly senses a blockage inside the level crossing and fires up warning lights to tell the hogger to slam on the brakes.
BUT, the system is NOT interlocked with main running signals.
And, from the diagrams presented about this incident and distances spaced out from the crossing, I doubt that the hogger would have had sufficient time to react at full tilt.
YES Syd, we still got a myriad of crossbuck level crossings out in the boonies.
Ones on main lines occasionally also possess a STOP SIGN.
Regardless of a train being on the horizon or not, the MOTORIST MUST STOP, look left and right and then proceed across if safe to do so.
I go over one of them when I escape the Mountain Racket when going west young man.
I have seen some motorists just slow down and NOT stop just continuing across.
The Broken Hill Xploder can hit 145 kph on this stretch of track.
Complete grade separation is the only truly SAFE solution.
But, that cost a mint, much more than our Aussie Mint holds over there in Sandgroper country.
Steve.
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  #6  
Old 13th December 2019, 11:49
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Originally Posted by TRP View Post
Is it just a cost saving that we have mostly half-barrier crossings - wouldn't it be safer to have full barriers?
Hi Tony, it's not a cost issue. Because AHBs are automatic (operated by the approaching train and NOT connected to the signalling system), it's deemed necessary to have an escape route by having no 'far side' barrier so that people and vehicles can exit from the crossing if the entrance barriers drop behind them.

As someone who drives trains over around flat 300 crossings a day, I believe this is deeply flawed for a number of reasons. Not least by the fact that pedestrians and cyclists on the right hand pavement don't have a barrier and can continue straight out onto the crossing and under the wheels of a train. With the distractions of mp3 players and mobile phones, we have a generation of Zombies with no spacial awareness - they just don't hear the sirens and don't see the wigwags. I've seen many near-misses, and the look of sheer terror on people's faces when a train flashes past just inches from them stays with you.

But as always, the people who make these decisions work in offices and have degrees in subjects like medieval poetry, so of course they know more about it than the peasants who've spent a lifetime doing the job.

Rant over (for now),

Cheers, BW
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Old 13th December 2019, 12:24
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Back again.

Actually someone mentioned the new 755 trains when I was at the Salt Mine yesterday, and I've just twigged what's happened here. RAIB have given us some clues in their initial report...

Quote:
Originally Posted by RAIB Report
The level crossing equipment was installed in 2000 and includes a predictor system which detects the speed of approaching trains so that the time interval between barriers being lowered and a train arriving is similar for all trains, irrespective of their speed.

The train was part of a new fleet which had been operating passenger services on this line since 6 November 2019.

Since the incident, Network Rail has modified the settings of this and similar level crossings on the line to reduce the chance of a repeat of this incident.

Our investigation will identify the sequence of events which led to the incident. It will also consider:

*the design, implementation and operation of the predictor system, including any effects of rail head contamination due to fallen leaves
*the design of relevant elements of the class 755 train and the process for accepting it for use on this route
*any underlying factors.
Any passengers trying to use Greater Anglia services at the moment are experiencing massive delays and cancellations. Remember that RAIB said..."We are considering....the design of relevant elements of the class 755 train and the process for accepting it for use on this route" It appears that GA's brand-spanking new 'LEGO' trains (well that's what the 755s look like) are throwing up some real problems and many have been withdrawn from service. A little bird told me that their wheel flanges are different from existing stock, and may not be operating the sensors fully. I'm a bit sceptical about this, but several different sources have mentioned it. It certainly sounds like RAIB thinks that the 755s have entered service without being fully route-assessed. Hmmm.

Also, with respect to the 'Predictor System', this route is being used to trial the new crossing technology for ERTMS (The so-called 'Digital Railway' and that In-Cab signalling shenanigans). I wonder if this Predictor System, which I've never heard of before is an ERTMS trial, and is not the prime culprit as far as this incident is concerned.

As ever, we await the investigation with bated breath.

Cheers, BW
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Last edited by Beeyar Wunby; 15th December 2019 at 09:50.
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