How long might it take to reopen the line near Stonehaven?

[GRALISTAIR]

Not surprised by the bridge. The kinetic energy it absorbed would be huge.

 

[Philip Phlopp]

Regarding the repairing of the route, has any consideration been given to accommodate the preparation works for overhead line electrification?

It would save having to close the line in the future.

There's a little bit more to electrification than sending some of the team out with some piles and a Movax. There will need to be a detailed design in place with specified piling locations before any groundwork can begin, and there will need to be a good ground survey (though I'm sure some of the data from the geotechnical people may find its way to the electrification planning team in the fullness of time). The specified piling locations have to take into account signalling, tunnels, culverts, bridges and will also have to take into account where tensioning and anchoring structures will be placed, as these require additional foundation structures.

But before any of that can be done, there needs to be a CGI of the route undertaken to assess where the signal sighting issues will arise and in these locations you desperately try and avoid tensioning or anchor structures and wire run overlaps, as they tend to require steelwork which gets in the way of your signals. Where it's not possible, signals may need to be moved to a gantry structure to aid sighting.

The boots on the ground bit is the end quarter of an electrification project, really.

 

[Bald Rick]

There's a little bit more to electrification than sending some of the team out with some piles and a Movax. There will need to be a detailed design in place with specified piling locations before any groundwork can begin, and there will need to be a good ground survey (though I'm sure some of the data from the geotechnical people may find its way to the electrification planning team in the fullness of time). The specified piling locations have to take into account signalling, tunnels, culverts, bridges and will also have to take into account where tensioning and anchoring structures will be placed, as these require additional foundation structures.

But before any of that can be done, there needs to be a CGI of the route undertaken to assess where the signal sighting issues will arise and in these locations you desperately try and avoid tensioning or anchor structures and wire run overlaps, as they tend to require steelwork which gets in the way of your signals. Where it's not possible, signals may need to be moved to a gantry structure to aid sighting.

The boots on the ground bit is the end quarter of an electrification project, really.

Exactly.

On another thread is the link to the Leeds - Huddersfield project consultation documentation under the Transpennine Upgrade. In this you can see the outline designs for the OLE gantries. This is for a project that won’t be on site for 2-3 years.

 

[adrock1976]

There's a little bit more to electrification than sending some of the team out with some piles and a Movax. There will need to be a detailed design in place with specified piling locations before any groundwork can begin, and there will need to be a good ground survey (though I'm sure some of the data from the geotechnical people may find its way to the electrification planning team in the fullness of time). The specified piling locations have to take into account signalling, tunnels, culverts, bridges and will also have to take into account where tensioning and anchoring structures will be placed, as these require additional foundation structures.

But before any of that can be done, there needs to be a CGI of the route undertaken to assess where the signal sighting issues will arise and in these locations you desperately try and avoid tensioning or anchor structures and wire run overlaps, as they tend to require steelwork which gets in the way of your signals. Where it's not possible, signals may need to be moved to a gantry structure to aid sighting.

The boots on the ground bit is the end quarter of an electrification project, really.

Exactly.

On another thread is the link to the Leeds - Huddersfield project consultation documentation under the Transpennine Upgrade. In this you can see the outline designs for the OLE gantries. This is for a project that won’t be on site for 2-3 years.

Thanks both for explaining the process regarding electrification.

Also, could it be explained what CGI means please?

 

[GRALISTAIR]

Kinetic Energy the bridge absorbed KE = 1/2 mv^2 a lot! Hence the delay

 

[Domh245]

Also, could it be explained what CGI means please?

I would think "Computer Generated Image" - in essence a computer fly through of what the route would look like with all the equipment in place, allowing them to identify if where they want to put a mast will obscure a signal

 

[Durradan]

Kinetic Energy the bridge absorbed KE = 1/2 mv^2 a lot! Hence the delay

Assuming my back-of-the-envelope calculation is right (2 x 72 tonne locos and 4 x 33 tonne carriages), that would be 139 Megajoules which, according to Wikipedia, is akin to having a decent-sized plane land on it.

 

[DB]

⁴

Assuming my back-of-the-envelope calculation is right (2 x 72 tonne locos and 4 x 33 tonne carriages), that would be 139 Megajoules which, according to Wikipedia, is akin to having a decent-sized plane land on it.

The rear power car didn't hit it, nor at least one of the carriages.

 

[pdeaves]

The rear power car didn't hit it, nor at least one of the carriages.

No, but those vehicles were still moving and contributing to the energy that had to be dissipated.

 

[GRALISTAIR]

Assuming my back-of-the-envelope calculation is right (2 x 72 tonne locos and 4 x 33 tonne carriages), that would be 139 Megajoules which, according to Wikipedia, is akin to having a decent-sized plane land on it.

The rear power car didn't hit it, nor at least one of the carriages.

No - but you get the gist - a lot of energy so full structural assessment of that bridge. It can NOT be just a matter of rebuilding the parapets.

 

[apk55]

I would have expected that the driver would have made a full brake application imediatly on derailing so that the speed would be reducing as it was crossing the viaduct so reducing the speed.

 

[najaB]

I would have expected that the driver would have made a full brake application imediatly on derailing so that the speed would be reducing as it was crossing the viaduct so reducing the speed.

IIRC, it was a couple hundred metres from the point of derailment to the bridge so there will have been almost no reduction in speed.

 

[Mcr Warrior]

Kinetic Energy the bridge absorbed KE = 1/2 mv^2 a lot!

Rather surprised when I heard that the train involved in this sad incident was returning Northbound at almost full normal line speed.

Because of the squaring in the calculation formula, that presumably would have significantly increased the kinetic energy that necessarily had to be dissipated.

 

[Bald Rick]

IIRC, it was a couple hundred metres from the point of derailment to the bridge so there will have been almost no reduction in speed.

There will, as various wheels dragging in the ballast has quite a retardation effect.

 

[najaB]

There will, as various wheels dragging in the ballast has quite a retardation effect.

Sorry, I meant specifically due to the application of the brakes.

 

[Durradan]

Network Rail have just published an update on repairs.

Our engineers are now relaying over 500 metres of track following the recent completion of work to repair the bridge and embankment damaged in the accident.

Work will continue into November as our teams remove and replace the damaged track and relay 400 metres of telecoms cables.

Teams have worked day and night over the past few weeks to complete repairs to 70 metres of bridge parapets and remove the crane pad built over the Carron Water for the recovery of the carriages in September.

A considerable amount of engineering work is also being carried out to repair and extend drainage systems on the railway track and lineside embankments at the site...

In summary, the bridge and embankment repairs have been completed so they've now moved on to replacing the track (>500 m worth) and telecoms cables (400 m). Looking like November at this stage.

Bit of a bummer for those of us getting the bus to work every day, but I appreciate you can't rush these things.

 

[hwl]

Network Rail have just published an update on repairs.

In summary, the bridge and embankment repairs have been completed so they've now moved on to replacing the track (>500 m worth) and telecoms cables (400 m). Looking like November at this stage.

Bit of a bummer for those of us getting the bus to work every day, but I appreciate you can't rush these things.

That isn't much work so I'd expect completion in October.

 

[swt_passenger]

Looks like the new parapet sections are fairly large concrete blocks, can anyone explain how they’d be secured to the underlying existing bridge structure, or will they just be laid on a fairly normal mortar bed?

Presumably the scour protection walls under the bridge is the work that was already taking place?

 

[najaB]

Looks like the new parapet sections are fairly large concrete blocks, can anyone explain how they’d be secured to the underlying existing bridge structure, or will they just be laid on a fairly normal mortar bed?

I expect that they would have drilled anchors into the existing brickwork.

 

[Taunton]

In summary, the bridge and embankment repairs have been completed so they've now moved on to replacing the track (>500 m worth) and telecoms cables (400 m). Looking like November at this stage.

Bit of a bummer for those of us getting the bus to work every day, but I appreciate you can't rush these things.

Hey Ho, why not let it wait until 2021.

Just to make the point, the big accident (far more so than this one) at Norton Fitzwarren, near Taunton, in 1940, which from photographs had just as much if not more destroyed track and signalling etc than here at Stonehaven, was all back and running, with civils repaired, signals reinstated (and this was a junction, not plain line) in ... 48 hours from it happening. Under wartime blackout conditions, with all the younger and fitter staff away in the military.

It's not just this comparison. Each decade, again and again, the ability to recover from any kind of incident gets ever longer.

 

[hwl]

Looks like the new parapet sections are fairly large concrete blocks, can anyone explain how they’d be secured to the underlying existing bridge structure, or will they just be laid on a fairly normal mortar bed?

Presumably the scour protection walls under the bridge is the work that was already taking place?

Looks like the a new in-situ poured concrete slab on top of the bridge so pretty easy to anchor something too. (The track height has increased over the years so plenty of depth available.)

 

[najaB]

Just to make the point, the big accident (far more so than this one) at Norton Fitzwarren, near Taunton, in 1940, which from photographs had just as much if not more destroyed track and signalling etc than here at Stonehaven, was all back and running, with civils repaired, signals reinstated (and this was a junction, not plain line) in ... 48 hours from it happening.

Most of the delay was due to the investigation. The site was handed back to NR about 20 days ago, they will have had to do drainage work, regraded the embankment and completed the bridge work in that time.

 

[swt_passenger]

Looks like the a new in-situ poured concrete slab on top of the bridge so pretty easy to anchor something too. (The track height has increased over the years so plenty of depth available.)

Yes of course, so there could well be hidden rebar joining the poured slab to the parapet blocks as well, which means it’s basically all joined together forming a whole heavy mass.

 

[GRALISTAIR]

Just to make the point, the big accident (far more so than this one) at Norton Fitzwarren, near Taunton, in 1940, which from photographs had just as much if not more destroyed track and signalling etc than here at Stonehaven, was all back and running, with civils repaired, signals reinstated (and this was a junction, not plain line) in ... 48 hours from it happening. Under wartime blackout conditions, with all the younger and fitter staff away in the military.

In wartime there are differing rules. No investigations just get the damned assets back in use ASAP

 

[Durradan]

That isn't much work so I'd expect completion in October.

I was wondering that. The landslip at Polmont that happened the same day as Stonehaven arguably caused more extensive damage to the railway (~1 km of new track needed, with associated cabling and electrification gantries, and ~300 m worth of embankment to shore up, plus fixing the burst canal in the first place) and those repairs took about 6 weeks. With the bridge and embankment at Carmont now sorted (after ~20 days since the handover from RAIB), bar any lingering access issues for materials etc, the rest should be relatively straightforward right?

They do also mention in the press release that "A considerable amount of engineering work is also being carried out to repair and extend drainage systems on the railway track and lineside embankments at the site." Do you think this would this be able to go on following reinstatement of the track, or would the line need to remain closed until that was completed too?

 

[furnessvale]

In wartime there are differing rules. No investigations just get the damned assets back in use ASAP

True, but even long after the war, accident sites were recovered a lot quicker than they are now.

The modern obsession with investigation is killing the job. By all means investigate, but how many weeks does it take to investigate why a cutting slope slipped in extreme wet weather?

Had a similar thing happened on the M8, would it still be closed?

 

[najaB]

The modern obsession with investigation is killing the job. By all means investigate, but how many weeks does it take to investigate why a cutting slope slipped in extreme wet weather?

But, by the same token, those detailed and painstaking investigations are the biggest reason why accidents are much less frequent now than they used to be.

 

[GRALISTAIR]

But, by the same token, those detailed and painstaking investigations are the biggest reason why accidents are much less frequent now than they used to be.

Indeed. Obviously 3 lost lives was tragic but the being the first deaths for 13 years shows a fantastic safety record.

 

[Durradan]

But, by the same token, those detailed and painstaking investigations are the biggest reason why accidents are much less frequent now than they used to be.

I wholeheartedly agree. I travel that route every day (in fact, I would have been on the train following the 0638 had it not been cancelled at ABD) and a few extra weeks getting the bus to work is worth it if reduces the chance of this happening again.

 

[Nicholas Lewis]

Rail Technology Magazine has another aerial shot

https://www.railtechnologymagazine.com/articles/track-repairs-begin-stonehaven-site

to get a flavour of the works ongoing