Liverpool Disruption 28 Feb 2017 - RAIB report released 30/11/17

[edwin_m]

The pan is air-operated so presumably there is some way of producing enough air under battery power to raise it.

 

[D365]

Ah, I was thinking more the braking system.

 

[Crossover]

I have been away for a few days but was hearing about the progress on the news - some excellent work by the Orange Army in getting the line open again at the speed in which it was achieved!

The pan is air-operated so presumably there is some way of producing enough air under battery power to raise it.

Under normal operation, probably yes, but having been stood for a week it's possible that batteries were too flat to operate the systems to get the pan to raise?

Basically if a plane lands short of the runway (before the railway) it will trip the OHLE before the plane hits it. Is more for the safety of the aircraft than trains as electricity an jet fuel don't mix well (and Kegworth disaster had happened shortly before the rail link was planned) but has the added benefit of bringing electric trains to a halt. Don't think it linked to signalling and doubt there much about it in public domain.

I flew into Manchester on Thursday and hadn't realised until then how close the approach came to the railway. Having passed over a few railway lines and stations (most yet to be identified), we passed over the airport junction pretty low - so much so it was possible to tell a 323 was approaching from Styal as we came in to land

 

[notlob.divad]

Under normal operation, probably yes, but having been stood for a week it's possible that batteries were too flat to operate the systems to get the pan to raise

At Lime Street, I believe that the pan is left raised on stabled 319 units because in the early days they had issues with the batteries dieing over night. We other the power being lost however, I don't know if the air seals where good enough to keep the pan up for 8 days.

 

[156441]

As a brief overview of the 319 air and electrical system I offer the following. (Shortened down before the pedents start)

The 319s only have one set of Auxellery batteries which are kept constantly charged while the pan is up and the lines are energised by the motor alternator.

If the overhead lines trip out these aux batteries will keep a train on emergency lighting and continue to power things such as drivers desk/GSMr/cab 2 cab and PA for around 30 mins.

At the point the OHLE goes off the MA stops turning and in turn the compressor stops providing air. Like all things as old as the 319s the air quite quickly bleeds off. The pan then lowers and the **** hits the fan.

Before this happens and the battery gets to low the driver is supposed to trip out the batteries (Known as Aux Trip) to allow enough power to 'cut-in' the unit when the power comes back on.

To 'Cut-in' a unit you need battery power. The 319 pan system has a tiny compressor in one of the middle cars that uses battery voltage to build enough pressure to push the pan against the overhead line. Once the pan is on a live line again the MA starts, the main compressor starts and all is good.

At Lime Street I believe the units were initially left Cut-In and by the time anyone realised in the chaos that ensued the batteries had gone flat. At this point you need an assisting unit to provide air to the failed unit to raise the pan.

However some of the units have a weird setup that requires battery voltage to run up the MA. So even after getting the pan up doesn't nessarily mean the MA will run up which in turn means the failed unit remains a failure and will require a battery charge on the depot.

I hope that makes sense it's 0210 and I'm not proof reading this as I've gone cross eyed typing it!!

 

[Blindtraveler]

Thanks for a facinating explaination!

I assume that there was a need to bang several together, shuv a loco on the front and drag to Bass?

 

[Crossover]

Thanks 156441 for the info

 

[2HAP]

The RAIB have opened a formal investigation.

Investigation into the partial collapse of a wall onto open railway lines, near Liverpool Lime Street station, 28 February 2017.

Our investigation will aim to determine the sequence of events. It will also include consideration of:

the history of the wall and the site adjacent to it
Network Rail’s management of the wall
findings of the structural examinations of the wall
the process used to examine the wall and the land supported by it
any relevant underlying management factors

https://www.gov.uk/government/news/partial-collapse-of-a-wall-onto-open-railway-lines-liverpool

 

[lineclear]

That confirms the hypothesis (expressed earlier in this thread) that the ground level had been built up behind the wall.

 

[theblackwatch]

The investigation report has been released, see https://www.gov.uk/government/news/...e-of-a-wall-onto-open-railway-lines-liverpool

Recommendations
The RAIB has made two recommendations to Network Rail. The first relates to being aware of those of its walls which have a potentially high safety consequence in the event of failure. The second is for Network Rail to review its assessment procedures for such walls, the use of open source data to identify changes in land use, and the provision of information on property boundaries to structures examiners.

 

[deltic]

I am intrigued by how train drivers were told to act in this incident. Driver of 1F91 heading towards Liverpool contacted signaller due to loss of power supply and signal changing from amber to red. Track circuits were showing tracks occupied although no trains present. Driver was subsquently told to proceed at caution and inspect the line - lost power again and was told to remain at stand. Train 1A60 was then allowed to leave Lime St and proceed at caution and inspect the line - got ten minutes out of Lime Street before discovering line blocked and then was stuck for 3hrs before it could get back to Lime Street.

Seems odd to let a passenger train to proceed into a situation where there was obviously a problem and which led to passengers being stuck for 3 hrs. After the Towy Bridge disaster, I would have thought the use of passenger trains to investigate what could be high risk situations would be frown upon.

 

[gimmea50anyday]

trains have to be sent through to "examine the line" for that exact purpose. To examine the line. With an unknown problem occuring as far as the signaller is concerned there's only really one way to establish what if anything is the problem. Send a train through!

 

[mikemcniven]

trains have to be sent through to "examine the line" for that exact purpose. To examine the line. With an unknown problem occuring as far as the signaller is concerned there's only really one way to establish what if anything is the problem. Send a train through!

But maybe they could have used an empty train to reduce the level of civilians in the area and who would get trapped. Kick everyone off the train and run it ECS to see whats happening before sending paying customers up.

 

[gimmea50anyday]

hmm... I get what you are saying, but then if the train is already in section then its not possible to detrain everybody first. Often a line examination reveals nothing amiss, so do we stop the job and incur massive delays to source an empty train and driver or just send the next one through at caution until the facts can be established? It's a juggling game which no answer will ever be the correct one

 

[Moonshot]

But maybe they could have used an empty train to reduce the level of civilians in the area and who would get trapped. Kick everyone off the train and run it ECS to see whats happening before sending paying customers up.

Not quite......Assessments of the Line happen a lot, I myself have been involved in a few when on a service train. Very often these have happened at a moments notice when it would have been impossible to detrain passengers anyway.....and as gimme50 points out a lot of the time its no fault found.

 

[deltic]

However it was clear there was a problem - a train had lost power twice and the track circuits were showing track occupied when there were no trains present.

Hopefully in future use of drones will allow track inspections in these type of cases to be done without using trains.

 

[Quakkerillo]

However it was clear there was a problem - a train had lost power twice and the track circuits were showing track occupied when there were no trains present.

Hopefully in future use of drones will allow track inspections in these type of cases to be done without using trains.

How quickly do you think an authorised drone pilot with appropriate drone type, camera will be available at any location? Also using drones in populate areas needs specific permissions, or new legislation to allow this on a more than once-only basis.

 

[Moonshot]

However it was clear there was a problem - a train had lost power twice and the track circuits were showing track occupied when there were no trains present.

Hopefully in future use of drones will allow track inspections in these type of cases to be done without using trains.

How would that work in tunnels?

 

[gimmea50anyday]

sending a service train through is often the best and only way.

last time I was asked to examine the line my front bogie ended up over a broken rail which stranded the train for 2 hours!

 

[edwin_m]

How would that work in tunnels?

Turned the TV on the other day and someone was flying a drone through the Post Office Railway tunnel, so any other rail tunnel ought to be possible.

However I also doubt there will be trained and equipped drone flyers accessible at a few minutes' notice - perhaps the MOMs could get that capability but as posted elsewhere recently they are few and far between anyway. So in most cases it would still be quicker to ask the driver of a convenient train to examine the line.

 

[deltic]

How quickly do you think an authorised drone pilot with appropriate drone type, camera will be available at any location? Also using drones in populate areas needs specific permissions, or new legislation to allow this on a more than once-only basis.

With police now deploying drones I would expect BTP to have the capability in most major cities in the relatively near future

 

[deltic]

sending a service train through is often the best and only way.

last time I was asked to examine the line my front bogie ended up over a broken rail which stranded the train for 2 hours!

Best way to inspect the line then train stranded for two hours! A classic oxymoron if ever there was one

 

[dosxuk]

Turned the TV on the other day and someone was flying a drone through the Post Office Railway tunnel, so any other rail tunnel ought to be possible.

There have also been videos in the media of drone flights through the crossrail tunnels. "Flights" which are clearly filmed by a camera attached to a train.

 

[deltic]

There have also been videos in the media of drone flights through the crossrail tunnels. "Flights" which are clearly filmed by a camera attached to a train.

This one clearly was flying free - you can see its shadow in places

 

[edwin_m]

There have also been videos in the media of drone flights through the crossrail tunnels. "Flights" which are clearly filmed by a camera attached to a train.

This one clearly was flying free - you can see its shadow in places

The lack of rails is something of a clue as well.