Storm Dennis' visit to the Welshpool & Llanfair Light Railway

[Tanllan]

Storm Dennis swept across Mid Wales on 15th & 16th February. The River Banwy runs parallel to the Welshpool & Llanfair Light Railway for about two miles. The river rose rapidly over the night of 15th February and by eight o'clock the next morning was less than a foot below the track in some places. I took the linked video during a couple of track inspections that were made before passenger train running commenced on Sunday 16th.

 

[Phil Bullock]

Hopefully no significant damage?
 

Being next to the river is a mixed blessing - scenic in summer but potentially destructive. Has there ever been significant damage to railway infrastructure? As with many Welsh rivers a relatively narrow and steep catchment means changes in level can be rapid.

 

Highest recorded level 3.59m in 2011 - only got to 2.59m in Dennis - so far!

 

https://riverlevels.uk/river-banwy-llanerfyl-community-llanerfyl#.Xk2Qv5X7TFg

 

 

[Nearholmer]

Very impressive at two levels:

 

- water level, obviously, and the Banwy bridge section shows just how blooming high it is; and,

 

- condition of trackbed and drainage, which looks to be very good a coping, which is tribute to the work of those who keep it that way.

[Tanllan]

17 minutes ago, Phil Bullock said:

Hopefully no significant damage?
 

Being next to the river is a mixed blessing - scenic in summer but potentially destructive. Has there ever been significant damage to railway infrastructure? As with many Welsh rivers a relatively narrow and steep catchment means changes in level can be rapid.

 

Highest recorded level 3.59m in 2011 - only got to 2.59m in Dennis - so far!

 

https://riverlevels.uk/river-banwy-llanerfyl-community-llanerfyl#.Xk2Qv5X7TFg

 

 

Phil,

 

On this occasion we escaped without any damage. The main road (A458) was flooded just west of Cyfronydd meaning our passengers travelling from the east had to travel via the 'Old Road' which does not flood (very much) but is rather steep and windy. If the gauging station at Llanerfyl reaches 3m then the railway will almost certainly flood. The last flood to do any significant damage, was 4 or 5 years ago and, required us to replace 30 tons of ballast in order to run the Santa Trains that year. In 1964 the Banwy Bridge nearly collapsed when one of the intermediate piers was damaged in a flood.

[Nearholmer]

How do you assess the fitness of the Banwy Bridge, given that the base of the piers is well under-water?

 

i was wondering about scour and undercutting?

[RJS1977]

If the train doesn't fall in, it's safe... ;-)

[Tanllan]

11 hours ago, Nearholmer said:

How do you assess the fitness of the Banwy Bridge, given that the base of the piers is well under-water?

 

i was wondering about scour and undercutting?

The intermediate piers have been rebuilt a few times over the years. As originally built one was on top of a fault line (the one that failed in 1964). In 1999 that pier was subject to a very extensive re-build involving the creation of a new deep foundation and a significant concrete cut-water. The river Banwy has a large variation in flow rate and the effects of Storm Dennis did not get near the 'Highest Recent' see this link<https://rloi.naturalresources.wales/ViewDetails?station=2062>.

 

Periodically, during a period of low water level, somebody has to get into the water and inspect the foundations for scour/undercutting.

 

Before the first train on 16th Feb a light loco was taken down the line and driven slowly over the bridge.

 

HTH