Pontcysyllte Aqueduct

[X Alan W]

21 hours ago, Flyboy said:

Just wait until the vegans find out what is sealing the trough plates. I've often wondered if there were ever railings on the offside. If I remember correctly there are square holes in the top of the side plates.

I was always of the understanding that the trough sections were made so that they could fit either way There is a aqueduct at Braire similar in design & construction ith the same material for gaskets " twix"sections

[1st ade]

1 hour ago, David Mack said:

Plenty of foot room there for anyone tempted to walk on the wrong side of the railings. It could be argued that the provision of railings in this form is actually encouraging such behaviour.

Such an argument was (I believe) submitted as an objection.

 

 

Together with the one that the presence of the railings positively encourages people to try and leap from the towpath side knowing the railings will stop them.

[billh]

9 hours ago, Boater Sam said:

 

Not been that way recently but seem to remember hearing that £100K has been spent fencing it.

 

Try three times that , from the horse's mouth ( the designers). All that pretty much wasted and the canal has been closed since September 2017 , locks 11 and 15 at Marple getting too narrow  for narrowboats, C&RT having  been warned about it over several years and done nothing. Yes, they rebuilt lock 15 last winter, had a grand re-opening that lasted 24hours  then closed the flight again because boats were  then getting stuck in lock 11.

[Derek R.]

Used to climb up the outside of a tower crane for the crac when I drove one in Cambridge. (The correct way was up the inside of the tower).

Walked across the River Lyn just above Lynmouth on a pair of wires one above the other in my teens. When they started oscillating half way across, it got seriously scary!

[BEngo]

5 hours ago, IanD said:

Might as well say that because somebody got killed by a train while walking along the rail, we should make such idiocy impossible...

The HSE /Railway Inspectorate are trying to do just that.  Hence there are miles and miles of expensive  new green or galvanised BS1010 fencing going alongside railways where previously post and wire fences were fine.  As for the pedestrian defences at level crossings.....

 

N

[Pluto]

On 13/12/2018 at 19:30, Flyboy said:

Just wait until the vegans find out what is sealing the trough plates. I've often wondered if there were ever railings on the offside. If I remember correctly there are square holes in the top of the side plates.

This is a translation of the Austrian canal engineer, Sebastian von Maillard's description of the jointing following his site visit in  1795 during construction:

So a 0.25 Zoll (9 mm) thickness of wood shavings in boiled in tar is inserted between their 4 Zoll (105 mm) wide flanges, and they are held together by bolts, which are tightened by several people with a 4 Füß (1.26 m) long spanner, so that the water cannot leak through the joints.

[Sea Dog]

8 minutes ago, Pluto said:

This is a translation of the Austrian canal engineer, Sebastian von Maillard's description of the jointing following his site visit in  1795 during construction:

So a 0.25 Zoll (9 mm) thickness of wood shavings in boiled in tar is inserted between their 4 Zoll (105 mm) wide flanges, and they are held together by bolts, which are tightened by several people with a 4 Füß (1.26 m) long spanner, so that the water cannot leak through the joints.

That's interesting. I always thought Welsh flannel and boiling sugar was used, but there's also sources saying white lead and iron boring waste were used with the Welsh flannel.

[Flyboy]

16 hours ago, X Alan W said:

I was always of the understanding that the trough sections were made so that they could fit either way There is a aqueduct at Braire similar in design & construction ith the same material for gaskets " twix"sections

This article says that it was intended to have offside railings but were never fitted.  https://www.historic-uk.com/HistoryMagazine/DestinationsUK/Pontcysylite-Aqueduct/

40 minutes ago, Sea Dog said:

That's interesting. I always thought Welsh flannel and boiling sugar was used, but there's also sources saying white lead and iron boring waste were used with the Welsh flannel.

I think you may be be correct, I have read somewhere that tallow & wool were used.

[ditchcrawler]

1 hour ago, Flyboy said:

This article says that it was intended to have offside railings but were never fitted.  https://www.historic-uk.com/HistoryMagazine/DestinationsUK/Pontcysylite-Aqueduct/

I think you may be be correct, I have read somewhere that tallow & wool were used.

A bit of info here from Bath University http://people.bath.ac.uk/jjo20/conference2/2008/MAIDMENT PAPER 28.pdf

Edited December 15, 2018 by ditchcrawler
Added the first 3 pages

[Pluto]

2 hours ago, Sea Dog said:

That's interesting. I always thought Welsh flannel and boiling sugar was used, but there's also sources saying white lead and iron boring waste were used with the Welsh flannel.

Iron filings seem to have been used fairly regularly on 18th and early 19th century constructions, the idea probably being that they rusted and adhered to the faces to be connected. You can find their use on early steam engines. Maillard also visited the cast iron aqueduct on the Derby Canal, where there seem to have been problems with the jointing, with at least one of the panels cracking during assembly and requiring replacement. I suspect that a variety of different types were tried. The suggestion of tar and wood shavings seems to have come from Mr Duncombe, who was the site engineer when Maillard visited. After his visit, Maillard returned to Austria and started construction of the Wiener Neustädter Kanal, a copy of an English narrow canal. The sections outside of Vienna still survive, though not navigable. His aqueducts were made from wood, as the technology for casting iron was not very advanced outside of Britain.