Friday 25 February 2022

Chain gang expands

That is the chain saw gang. Martin and Andrew, together with Nick, Maurice and Gary from the clearance teams attended classes on chain saw maintenance and felling up to 200mm diameter trees. The hardest part of the classes was finding some suitable trees to practice on. Most of those we need to fell are either too large or are located on embankment or cutting slopes that are too steep for beginners. After a bit of searching a pair of multi-trunk ash trees on the down side near Hayles Abbey Halt were selected. These are now piles of logs in Winchcombe Yard. Also covered in the classes was use of a polesaw, a small chain saw on a long telescopic handle. The practice items for this were the trees overhanging the end of the third rake siding on the up side at Winchcombe.

Just a load of stumps, a pile of brash and logs out of site. Hard to tell who is under the PPE!

Polesaw, the ideal tool for trimming overhanging branches. The guy standing by the carriage is the class instructor.

Thursday 17th February

The five members of the team not learning chainsawing formed two groups today.

Two formed the construction squad at Working Lane. They dug out one side of culvert 24C outlet for the concrete base of the new headwall. They also moved the last remaining concrete blocks from the top of the haul road opposite the Royal Oak down to the hardstanding area at the bottom of the haul road. These now form the boundary of the area to be extended.

Culvert 24C, temporary extension pipe and nearest camera excavation for headwall and concrete apron. Digging the other side of the pipe will be another day's work. Heavy clay abounds here.

The remaining three members of the team continued with internal visual inspections and clearing of culverts. They covered Bishops Cleeve to Two Hedges Road, with culverts/cross pipes 37E, 37F, 37G, 38A, 39A, 39B covered. Most of the culverts on the Gotherington to Bishops Cleeve stretch were rebuilt in 2017 or 2018. Consequently are are in good condition. Besides a couple of loose coping bricks, the only significant items for these is installation of appropriate safety fences or markers. Annual vegetation growth often obscures the edges the head and wing walls, which is a safety issue. Not all lineside workers have the knowledge of the location of all the structures.

37G is a multi-part culvert. First from the low mileage end is this headwall where the stream from Nottingham Hill joins the down side to drain ditch, footpath behind fence on right. (Photo by Dave)
Second headwall where the stream goes under the footpath again, the footpath goes under bridge 38. (Photo by Dave)

On the high mileage end of bridge 38, 37G is a pipe with an access chamber. That single thick cover is probably GWR origin, it is certainly heavy! (Photo by Dave).


Third headwall, where 37G exits to become a toe ditch at the foot of the down side embankment. This has the safety fences which we will be installing on many other headwalls soon.
Flowing away alongside the Willow Drive mobile home park towards culvert 38A. First of many land drains from the mobile home park on the left. (Photo by Dave)

One big change on the culvert inspections this week was the quantity of water. After a dry January and early February, storm Dudley brought a lot of rain to the Cotswolds. Consequently most of the flow reports were ‘substantial’ or ‘good’ rather than ‘damp’ or ‘a trickle’. Additionally in a couple of places the vegetation clearance is only partial; the levels in the ditches were too deep even for wellies. We will have to revisit these in the spring or summer which we hope will be drier.

Finally a couple of hours in the workshop saw the completion of three more replacement milepost heads. These are 5 miles, the first of the Broadway extension ‘house number’ replacements; 10 miles for Didbrook where the current post only has half a head, and 13¾ miles at Gotherington; one of those that is currently just a bridge rail post.

Three more more mile post heads ready for fitting (well will be once the black paint on the screw heads has dried). The heads are upside down on the workbench to stop them falling over.

Thursday 24th February

Only five of the team in today; the main task being yet more vegetation clearance and visual internal inspections. A team of three headed to Two Hedges Road bridge at Bishops Cleeve to commence with culvert 40A and work south to Kayte Lane, culvert 41C. With the weather improving in the afternoon, they were also able to clear the vegetation from the cess manholes all the way down to the RDA crossing at Cheltenham. The end of this round of inspections is now in sight! In fact there are only two more to complete, both of these are south of Hunting Butts tunnel where there is no railway on the trackbed.

Culvert 40A is a syphon, this cover marked with a blue asterisk is the centre washout. We don't remove these for internal visual inspections!

Between 40A and 40B on the down side is this little mini-headwall. It is not culvert or even a cross drain. It is where a pipe connects the cess drain to the toe ditch that follows the boundary down to culvert 40B.

The only dry culvert today, 41A. Changes to the levels on the adjoining field on the upstream side (the down side in railway parlance) result in this one only flowing during very wet spells.

Damage to a cess drain manhole lid near Southam Lane bridge. Even with reinforcing bar these lids will not support the weight of a heavy object or vehicle. One more to add to the list of replacements. (Photo by Roger)

The other two members first headed to Working Lane to deliver some more infill for the hardstanding. Whilst there they checked the temporary extension to the outlet of culvert 24C – it is all holding well, no storm damage. Also on 24C, the regular clearing of the grill protecting the outlet under the boundary fence was attended to. Another odd job was removal of silt from the new apron on culvert 24B haul road inlet; probably the storms washing clean from our construction activities earlier in the year.


Culvert 24C exits railway land through a pipe protected by this grill; removing the debris and the level in the ditch drops over 2 inches.

Then it was on to Bishops Cleeve, culvert 37G. Last weeks inspection team reported some debris in the chamber of this culvert on the high mileage side. An easy job for the long handled grab; once the heavy old thick lid was removed. 37G is unusual in that it does not go under the railway; but a footpath, twice. It takes a stream that flows down Nottingham Hill onto railway land; then back under the footpath by accommodation bridge 38 to flow at the foot of the down side embankment to join the stream that flows through culvert 38A. This length borders the Willow Drive mobile home park, it was inaccessible until recent clearing by the clearance teams. Some minor cleariing with rakes improved the flow, but again a thorough clear out will have to wait until drier weather. Some noticeable undercutting of the raised land in the mobile home park has occurred, this maybe a result of suspected restrictions in the outflow of culvert 38A outside of GWSR land. We are in contact with the Gloucester County Council flood officer to progress further inspections.

Inside the chamber of 37G; not silt but medium sized gravel.

 

Under cutting of the raised land in the mobile home park by the ditch between 37G and 38A.

Finally it was down to Kayte Lane to join up with the other gang. The combined team were then able to remove most of the debris in the inlet and outlets of Culvert 41C; and a large overhanding branch over the outlet. This culvert is a large two pipe syphon, interestingly the two cess drains also have syphons under the foot crossing here.

Inlet ditch of 41C at Kayte Lane, after clearing. The level had dropped over 3 inches.

Inlet side 41C after clearing, the brick pillar divides the inlets of the two big syphon pipes.

Outlet side of 41C after removal of overhanging dead branch and as much clearance as possible without getting feet wet.

With the ‘official’ bird nesting season starting on 1st March (and running to end of August) our brush cutters will be having some well earned rest. The clearing items we need to revisit are mostly grass trimming and reed removal, plus some digging to remove silt. Several weeks of warm and dry spring weather is what we need now!


3 comments:

  1. If l understand a syphon correctly , l can see that gravel and silt is likely to enjoy the trip to the bottom but surely not keen on the upward journey. How often does it need cleaning out and how is that done please ?

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    1. Hyboy - thanks for the interest by asking a very good question. Yes, over time silt and other debris will be washed into the lowest part of the syphon and will eventually restrict the flow so much to cause flooding on the inbound side. Cleaning out is normally done by getting in specialist contractor to perform a Jet-Vac. This is a combination of high pressure flushing and sucking, like a bit vacuum cleaner. It is not cheap, so we don't do it unless absolutely necessary. We have 5 cross drains or culverts which are syphons, plus a few more on cess drains. Most have a silt trap on the input side, which we check and clean out regularly. At Kayte line the trap is formed by stop planks, like those you see on canal locks. Some of the single pipe syphons, like culverts 7A and 39B, have an inspection/drain cover in the lowest point. None of those have been opened for a long time!
      Andrew

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