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Journey by Journey => Bristol (WECA) Commuters => Topic started by: ellendune on February 22, 2023, 10:39:18



Title: Sea flooding on Severn Beach Line 22/02/2023
Post by: ellendune on February 22, 2023, 10:39:18
GWR on Twitter

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Due to the sea flooding the railway between Clifton Down and Severn Beach, the line is blocked.

Train services running to and from these stations may be cancelled, delayed, or revised.


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: Red Squirrel on February 22, 2023, 11:28:45
GWR clearly think the River Avon had a promotion...

Meanwhile:

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Flood alert for Tidal River Avon at Bristol, Pill and Shirehampton

Tides are expected to be higher than usual due to spring tides. First forecast high water is 20:30 on 21/02/23. Second forecast high water is 08:45 on 22/02/23. All times are local and refer to the high water time at Avonmouth. Plan driving routes to coastal roads, which may be flooded. Please be careful along beaches, promenades and coastal footpaths and roads. We expect flooding to affect the tidal River Avon from Sea Mills to Conham in Bristol and between the Avonmouth Bridge and Shirehampton Park including Pill and Shirehampton. We are closely monitoring the situation. Our incident response staff are closing flood gates. This message will be updated Wednesday 22/02/23, or as the situation changes.

Sourve: gov.uk (https://check-for-flooding.service.gov.uk/target-area/112WATAVN1)


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: Red Squirrel on February 22, 2023, 11:34:45
Looks like a couple of trains were cancelled this morning; all appears back to normal now according to Realtime Trains...

Update: gwr.com says normal service after 13.00. Looks like they may be making use of the CFN turnback.


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: DaveHarries on February 22, 2023, 21:26:38
Looks like a couple of trains were cancelled this morning; all appears back to normal now according to Realtime Trains...

Update: gwr.com says normal service after 13.00. Looks like they may be making use of the CFN turnback.
Not quite: my parents went off to Oxford for the day and found, when they got back into Temple Meads at about 1630, that they could not get a train to Sea Mills because the bridge there was being checked over.

They obviously opened the line at some point because 2K54 (1810 Weston-s-Mare - Severn Beach) got through to Severn Beach but its return 2K57 (2001 Severn Beach - Bristol Temple Meads) is, as at 2130 still at Avonmouth from which it should have departed at 2010! The line is again closed from Shirehampton to Clifton Down as I write this and the Clifton Down turnback is again in use. Screenshot attached from OpenTrainTimes.

Online sources give tide as being due at 14.08m @ 2108hrs.

Dave

Edit @ 2210hrs: Just come back from Sea Mills where I noted that the high water mark was only about 1ft above the section of path that runs under the bridge on the station side. High tide forecast at 14.28m @ 0926 for Thursday morning (23rd February) according to https://www.tidetimes.org.uk/port-of-bristol-avonmouth-tide-times-20230223


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: Red Squirrel on February 23, 2023, 08:25:30
GWR are running a shuttle service between BRI and CFN this morning, at approx 26 min intervals.


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: Red Squirrel on February 27, 2023, 17:27:22
I had a look under the viaduct at Sea Mills on the weekend. Presumably these girders are supposed to brace it during high tides. I can see why NR might be a bit worried!

(https://fosbr.org.uk/wp-content/uploads/2023/02/sea_mills_viaduct_20230226.jpg)


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: brooklea on February 27, 2023, 19:03:31
I had a look under the viaduct at Sea Mills on the weekend. Presumably these girders are supposed to brace it during high tides. I can see why NR might be a bit worried!

(https://fosbr.org.uk/wp-content/uploads/2023/02/sea_mills_viaduct_20230226.jpg)

Looks pretty ‘non-structural’ to me! :o


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: Red Squirrel on February 27, 2023, 23:03:19
Looks pretty ‘non-structural’ to me! :o

Especially the bit stuck in the mud in the foreground...


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: froome on February 28, 2023, 09:05:20
Indeed. I've stated here before my fear each time I've walked under the bridge following the Avon Walkway path on the mudflats, as there is much corrosion evident all around. If you are in a train, you obviously don't see the state of the pillars, so travel completely unaware.

Presumably as a first measure, NR could install a speed limit over the bridge, but would that help at all?

If not, any work to the bridge would obviously mean the closure of the line beyond Sea Mills (and possibly beyond Clifton Down, as would Sea Mills be able to act as a station with works so close by?). It would be ironic if that happened on the day Portway Parkway opened!


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: Red Squirrel on February 28, 2023, 09:40:25
Indeed. I've stated here before my fear each time I've walked under the bridge following the Avon Walkway path on the mudflats, as there is much corrosion evident all around. If you are in a train, you obviously don't see the state of the pillars, so travel completely unaware.

Presumably as a first measure, NR could install a speed limit over the bridge, but would that help at all?

If not, any work to the bridge would obviously mean the closure of the line beyond Sea Mills (and possibly beyond Clifton Down, as would Sea Mills be able to act as a station with works so close by?). It would be ironic if that happened on the day Portway Parkway opened!

I am not a signaller, but my understanding is that (without some sort of pilot working) trains can only be turned back at Clifton Down and Avonmouth.

My assumption is that the bracing girders were added some time after the bridge was originally constructed. As such, they could presumably be replaced if (and it may be a big 'if') the columns are in a reasonable state. From the look of the girders, it would possibly be better to remove them to prevent damage to the columns when they inevitably collapse.


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: Mark A on February 28, 2023, 12:02:01
Seamills, the bridges, from across the river. Photo from 2008.

Mark

(https://i.postimg.cc/C5CZBdjG/seamills-rail-bridge-full.jpg)


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: Red Squirrel on February 28, 2023, 12:24:29
This picture, taken around 1963, shows the girders in a better state. I wonder if they've been painted since?

(https://upload.wikimedia.org/wikipedia/commons/e/e7/Harbour_%26_railway_bridge%2C_Sea_Mills%2C_Bristol_c1963_Scans487_%2810430682163%29.jpg)
Gillett's Crossing from Bristol, United Kingdom, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: Western Pathfinder on March 01, 2023, 08:47:54
Considerably less load bearing mud back in the day !
With regard to speed restrictions for the use of the bridge,as it happens all services departing Sea Mills in the direction of Shirehampton ,acceleration to line speed takes place after crossing the structure and those in the direction of Clifton have already slowed to station approach speed before the bridge.


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: ellendune on March 01, 2023, 13:25:48
The load that a column can take is partly determined by it slenderness (broadly ratio of height to width). If this ratio is high then the column can buckle under load.  The effective height of the column can be reduced by installing cross members. This is most elegantly shown in the 'scissor arches' under the tower of Wells Cathedral.

I presume, therefore, that these steel cross members were installed to strengthen the columns.  It may be that if the only traffic is DMUs these are not needed any more (I assume the freight goes via Henbury).  However they would be fairly simple to replace. 


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: TonyK on March 01, 2023, 15:09:04
Indeed. I've stated here before my fear each time I've walked under the bridge following the Avon Walkway path on the mudflats, as there is much corrosion evident all around. If you are in a train, you obviously don't see the state of the pillars, so travel completely unaware.

Presumably as a first measure, NR could install a speed limit over the bridge, but would that help at all?


I seem to recall a 5mph limit over the bridge, that being some 10 years ago.


It may be that if the only traffic is DMUs these are not needed any more (I assume the freight goes via Henbury).   

The rubbish trains between Brentford and Sita arrive loaded via Henbury, but the empty trains return via the Severn Beach line. I assume that saves a change of direction at Hallen Marsh when more lightly loaded - but still heavy.


Looks pretty ‘non-structural’ to me! :o

It is now. :)


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: johnneyw on September 02, 2023, 12:04:24
A Facebook page for the Beach Line reports that services seem to be suspended at present due to high tides.  There a couple of pictures of the bridge over the confluence of the river Trym with the Avon where the water level isn't that far short of the track.
Another website showing arrival and departures at Montpelier for the line is showing no services at present either...which is curious as services could surely still turn back at Clifton Down Station, giving a partial service?


Edit:  It's just dawned on me that there's RMT industrial action today.....flood tide came at a helpful time in that case!


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: stuving on March 08, 2024, 22:14:08
I may have commented before that, for an island nation, we don't seem very conscious of tides and how they vary. Tide forecasts and warnings have a very narrow audience. Obviously it's different in France ...

To say how big tides will be over a wide area you need a coefficient, used to scale up (or down) the average tide height at each place. I have seen different ones used here, so we do not appear to have a standard definition. There is (of course) a standard French one, with extreme values of 20 and 120. Next Monday or Tuesday this month's peak (at spring tide) will be 118 - not far short of the maximum. This is the highest tide for ten years, and that made it national TV news in France.

Local tides depend not just on the global and regional factors captured by a coefficient valid for the whole Atlantic and channel costs of France, but on all sorts of local ones too. So the tides at Sea Mills may not be the highest for ten years - but expect something of that order. 


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: Hafren on March 08, 2024, 22:54:18
The reports of issues near Avonmouth correlate reasonably well with the equinoctial spring tides...

https://ntslf.org/tides/hilo?port=Avonmouth

Perhaps this data needs to be fed into Journeycheck!


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: ellendune on March 09, 2024, 19:22:16
I may have commented before that, for an island nation, we don't seem very conscious of tides and how they vary. Tide forecasts and warnings have a very narrow audience. Obviously it's different in France ...


I know about the tides, but I am not conscious of them of a day to day basis perhaps because I live in north Wiltshire on the 125m contour line.  Even if all the ice sheets melt and the sea rises by 70m I am still not sure that I would need to be conscious of them here!


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: TonyK on March 10, 2024, 20:44:48

I know about the tides, but I am not conscious of them of a day to day basis perhaps because I live in north Wiltshire on the 125m contour line.  Even if all the ice sheets melt and the sea rises by 70m I am still not sure that I would need to be conscious of them here!

I'm around 80 metres AMSL so would need a boat to get to the station. On the plus side, we would both find the value of our homes increasing significantly.


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: Mark A on March 12, 2024, 11:39:43
Here comes the sea. Bristol this morning, video from Twitter.

Mark


https://twitter.com/beardedjourno/status/1767482265930449047 (https://twitter.com/beardedjourno/status/1767482265930449047)


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: grahame on March 13, 2024, 05:56:45
From National Rail

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Expected sea flooding the railway between Dovey Junction and Aberystwyth / Pwllheli means lines will be closed from approximately 09:00. As a result, no trains will be able to run between these stations.

We expect disruption to continue until 12:00.

From GWR

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Cancellations to services between Severn Beach and Clifton Down via Avonmouth

Due to flooding between Clifton Down and Avonmouth the line is blocked. Disruption is expected until 12:00 13/03.

Train services between Severn Beach and Clifton Down via Avonmouth will be cancelled or revised. Some stations between Avonmouth and Clifton Down will not be served.

GWR have also provided substantial customer advice - thank you

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Apologies to customers wishing to use the Severn Beach line today. As a consequence of flooding in the Sea Mills area, the line is currently blocked between Avonmouth and Clifton Down.
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We're operating a shuttle service between Severn Beach and Avonmouth utilising a three coach train. The departure times of these can be found in journey planners and at stations. 8-seat taxis will then replace trains between Avonmouth and Clifton Down in both directions. Trains to / from Bristol Temple Meads will start / terminate at Clifton Down. Please be prepared to change trains at either Avonmouth or Clifton Down depending on where you're travelling from.
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This plan is expected to remain in place until midday.
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Please note that the pick up / drop off point at Clifton Down will be in the pay and display car park on the opposite side of the tracks to Sainsbury's just off Whiteladies Road.
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We've also requested ticket acceptance on local bus routes in the area to accept our customers however such agreements have not yet been confirmed.
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During this disruption if you wish to use local buses as an alternative means of transport and the local bus is not accepting GWR tickets please purchase a ticket on the bus, keep it and send it, together with your train ticket, to us to claim for a refund.
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If you require further information please speak to our station or onboard staff, use the Customer Help Points located on platform level, tweet us @GWRHelp via X platform (formerly Twitter) or call National Rail Enquiries on 03457 484 950.
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Once again we apologise for any inconvenience caused to your journey with us today.


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: CyclingSid on March 13, 2024, 07:16:19
and another result https://www.bbc.co.uk/news/live/uk-england-gloucestershire-68533039 (https://www.bbc.co.uk/news/live/uk-england-gloucestershire-68533039)


Title: Re: Sea flooding on Severn Beach Line 22/02/2023
Post by: Mark A on March 13, 2024, 08:33:43
From National Rail

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Expected sea flooding the railway between Dovey Junction and Aberystwyth / Pwllheli *snip*.

*snip*

I'm trying to recall if previous to this I've read the (honest) attribution 'Sea flooding' as a reason for a railway line closing. It's a phrase that's not yet caught on when referring to flooding of the branch to Looe. With Dovey Junction though, the water is really close at hand there and even when the line doesn't flood the amount of wrack that collects by the station tells a tale.

The railway there is, though, built out of reach of ordinary tides and surges. At nearby Penhelig, below the railway and along the shore, traces of an attempt to build a road that was far too close to high water level if not actually beneath it, as can be seen in the photo below, perhaps the walls are the base of a short causeway, but even so, very vulnerable.

Mark

https://i.postimg.cc/1t4XHyfS/dovey-estuary-rails-1200.jpg (https://i.postimg.cc/1t4XHyfS/dovey-estuary-rails-1200.jpg)



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