Wednesday, August 28, 2024

Automatic Telephone Exchanges

A panel of stepping switches at a telephone exchange. Public domain image via Wikimedia Commons.

 

In Ireland, unlike the UK, we skipped having transistorised telephone exchanges and went straight from electromechanical (using relays, coils and motors) step-by-step or more modern crossbar systems to digital versions. When I was in the boy scouts in the 70s, I remember the whirring and clicking coming from the small telephone exchange building adjacent to our den (located in the tennis club building), as the exchange switched calls. Electrical pulses from a subscriber's telephone (known as pulse dialling, now replaced by tone dialling) caused a shaft on one of the mechanisms in the exchange to turn by a varying angle, the angle depending on the number of pulses. Each number from 0 to 9 on the dial of a telephone handset generated a different number of pulses. The shafts on the mechanisms in the exchange had an arm or arms attached, with electrical contacts on the end of the arm. As the arm swept around (usually limited to a half circle), it made contact with another set of stationary contacts, the process enabling a call to be connected to another number locally. Trunk calls to another "area code" would be sent to the exchange in Naas to be distributed to other local exchanges. From what I recall, in the early 70s, either Byrne's supermarket in Kilcullen or Athy still had a handset without a rotary dial, sitting near the meat counter at the back of the shop, presumably dating back to before the days of the automatic exchange.
 
This is an RTE report from 1989 about the changeover.

No. 131 — Built in Glasgow in 1901, Withdrawn in 1963


I could look at steam trains all day.
No. 131 isn't the oldest locomotive in the RPSI's collection of vintage steam trains. That honour goes to No. 186 which was built in the 1880s and worked as a goods engine but also on passenger trains. Her last operation was hauling beet in 1962/63. Up until a few years ago, she was the oldest engine still operating on the mainline, but is now out of service and on display at Whitehead museum. No. 461, another locomotive in the collection, was built for the Dublin and South Eastern Railway, but was delivered in 1922 during the Civil War. Rather than risk the danger of it being destroyed, like many engines, rail lines and bridges, she was stored in the North by the GNR until the end of the conflict.
The Railway Preservation Society of Ireland is an all-island organisation registered as a charity and run by volunteers. It restores and maintains engines and also runs excursions, mostly during the summer months, but with special events at Easter, Halloween and Christmas. It's based in Whitehead, near Carrickfergus in Northern Ireland, with workshops that restore the engines. It also has an operation in Inchicore where volunteers can help with the maintenance of carriages.
Steam traction ended in Ireland in 1963 after which most engines were unfortunately scrapped. Only a handful were left to be exhibited in museums or restored to operate on the mainline.

No. 186, built in the 1870s and up until a few years ago, the oldest locomotive still running on the mainline. © Eugene Brennan

Fixing Mistakes on OpenStreetMap

Openstreetmap map. Image courtesy Openstreetmap contributors

This is more geography than science but I often use Open Street Map because it shows local road numbers (which aren't indicated on Google Maps or OSI's maps), trails and paths, things of local interest such as antiquities, sculptures, parks etc. It's also the map provided free by most hiking apps. OSM is open source, which means that just like Wikipedia, the public can edit it, or even build a new customised map for their own use based on it. However there can be errors (just like on Google Maps). I had to get GM to include the canal from Naas to Corbally, because half of it was missing, and have rerouted rivers too which were in the wrong place. I've always liked maps and have been correcting the errors on OSM over the years for Kilcullen. If anyone wants to check and make corrections, you can view OSM here.

https://www.openstreetmap.org/#map=17/53.130420/-6.744070

Water Pumps, a Mystery Arch and New Abbey

Image courtesy OSI (Tailte Éireann)
I met John Brady in New Abbey Cemetery this evening and amongst other things, we were talking about hydraulic rams or ram pumps, According to John, there was one located near one of the three small bridges over the Mill Stream, the newest of the bridges carrying the mass path. The pump I think was for pumping water to New Abbey house. I knew there was also a hydraulic ram located on the Gilltown estate, north of the lake, as it's visible on the circa 1900 25" OSI map.
I still haven't worked out what the small arch was for, the top of which used to just protrude above the water line of the stream. This was located in a wall adjoining the stream, between the mass path bridge and one of the two older ones further south. It was visible when we were kids, looking for the legendary, but highly unlikely tunnel connecting New Abbey to the town or Old Kilcullen. We were able to push long sticks into the archway, so the cavity went in some distance under the wall. The area at the base of the wall is now however choked with weeds, so the arch is no longer visible. Possibly it was a drain from the house that used to be just inside the wall and arch at the end of the cemetery car park, (visible in the the Lawrence Collection photo of New Abbey I linked to in the comments). There were also other buildings in the area, visible on the first edition 1837 OSI map. The field occasionally floods (the last time in 2015 or 2009 from what I recall) and another possibility is that this could have been a drain to allow flood water to flow back into the stream. It could also have been the water intake for a channel that flushed waste in a crude latrine system, something I've seen at the ruins of the woollen mill in Ballymore. Maybe a question or a piece of information to add to Michael O'Connell's jigsaw. Anyway this took me down a Wikipedia rabbit hole (a regular occurrence!) to read about self-powered water pumps which were often used for raising water to a higher level before electricity was available.

Ecclesiastical Sanitary Fittings

Piscina fragment in New Abbey Cemetery, Kilcullen, Co. Kildare. © Eugene Brennan

Well sort of! I always wondered what this stone object was in New Abbey Cemetery. A slab with a seemingly conical depression and hole at the bottom. It's located near the small entrance gate to the cemetery. I originally thought it might have been part of a door jamb and decorative keeper for a bolt, but I came across a photo of a lavabo or more correctly a piscina on an archaeological website and it appears the stone piece in New Abbey may be the drain section of what remains of a piscina. A lavabo is an old term for a wash basin and in an ecclesiastical context the basin is used by clergy for ritually washing hands before the consecration. A piscina is a basin for washing communion vessels and the drain is known as a sacrarium. I queried it with Wexford archaeologist Colm Moriarty who runs the Irish Archaeology website and Twitter/X account of the same name. He confirmed my suspicion and agreed that it was more than likely part of a piscina. What seems like a conical depression actually appears to be an inverted pyramid, with an octagonal base and eight sloped faces

Investigating the Bridges of the Sallins Bypass and Cycle Paths in Naas and Sallins

The new rail bridge over the Sallins Bypass. © Eugene Brennan

I cycled to Sallins on Sunday to investigate the Sallins Bypass which opened in April of 2021. I don't normally venture to this part of the county because of the amount of traffic on the roads and my trips are usually cross country through south Kildare or to west Wicklow. The R448 Kilcullen to Naas road isn't exactly safe for cycling on, so I normally go all over the world to get to Naas, via Mile Mill, Brannockstown, Carnalway, Harristown and Mullacash before emerging out onto the R448 just south of Killashee. From this junction, there's a short section of busy road without a hard shoulder as far as Killashee MDNS, but after that it's possible to cycle all the way to Sallins using a combination of new cycle paths in Naas and along the bypass plus the roads along the canal (sections of which are now closed to traffic).
 
My route to Naas and Sallins. © Eugene Brennan

The Bypass Bridges

Construction was a joint venture between SIAC and Colas, and six new structures had to be constructed for the bypass. One of the bridges extends over the Grand Canal and two had to be constructed over the River Liffey because of the way the river meanders. All of these bridges have quite large spans when viewed from underneath. Irish Rail were responsible for constructing the underbridge where the bypass runs under the railway, this bridge located 60 metres from the rail bridge on the road that runs along the canal to Digby Bridge.

Cycle Paths

A segregated cycle path runs along the bypass from its junction with the Clane road north of Sallins, as far as the Osberstown overbridge. At this point, the cycle path ends and cyclists can leave the bypass to make a connection to the Osberstown road, just north of where it crosses the canal. There are also cycle lanes on the Sallins Link Road from its junction with the bypass as far as the centre of the town. In Sallins itself, cycle paths run from the south of the town before the Osberstown road turn off as far as the railway bridge in Sallins. After that, heading northwards, there's a break in the path before it begins again north of the canal bridge.
 
Cycle path on the Sallins Bypass. © Eugene Brennan


One of the bridges over the River Liffey. © Eugene Brennan



© Eugene Brennan

An access stairway to the underside of one of the bridges. © Eugene Brennan


 
© Eugene Brennan

 
Overbridge for the bypass as it crosses the Grand Canal. © Eugene Brennan

 
 
Some more information on construction here:

Saturday, August 17, 2024

A Little Bit of Civil Engineering

New bridge over the Lemonstown Stream/Toor Brook. © Eugene Brennan


I spotted this on the way back from my cycle on the woodland trails near Turlough Hill on Sunday evening. Construction of a new bridge/culvert over the Toor Brook and widening of the road seems to be progressing well at Alliganstown. The existing bridge on Mill Lane was narrow and on a bend, with no crash barrier or parapets, so a vehicle could have potentially ended up in the stream if it met another and had to take evasive action. Farm vehicles on these types of lanes are common and they usually take up the full width of the road, so hopefully this will make things a bit safer.
Well done to Cllr. Tracey O'Dwyer who proposed the motion in January, 2022 to carry out an assessment of the bridge. The lane provides access to six farms and seven households, according to the motion.
 
 
© Eugene Brennan         

 
© Eugene Brennan

© Eugene Brennan

© Eugene Brennan
The waterway is described in the council motion as the Lemonstown Stream. Toor Brook is from Openstreetmap and the 25" circa 1900 OSI map, but often geographical features and placenames can have several names.
 
This document lists the council motion:
https://kildarecoco.ie/.../190122%20%20Agenda...

How Kilcullen Gets Its Power and Poulaphouca Dam

Construction of the Poulaphouca Dam. Image courtesy O'Dea Photograph Collection, The National Library of Ireland. Photographer James O'Dea

The Liffey Reservoir Bill was signed into law and became an act in 1936. Construction of the dam commenced in 1937 with flooding of the Liffey Valley beginning in 1940. The hydroelectric power station was finally commissioned in 1947.

How Does the Dam Work?

The dam simply builds up a pressure head, similar to that produced by the weir that used to be located north of the bridge in Kilcullen, water being kept at a high level so it gains potential energy and can release that energy to do useful work as it falls. Work has a specific meaning in physics and is defined as "when a force moves a body through a distance". In this case, work is done when water loses momentum and creates a force as it decelerates on hitting turbine blades (just like a hammer head hitting a nail). Water is carried from the dam, under the N81, to the power house, located several hundred metres away, via two, 2 m diameter steel pipes or penstocks. Two 15 MW Kaplan turbines at the generating plant produce electricity which is stepped up to a high voltage for transmission to a 110 kV substation near Stratford-on-Slaney.

How Does Kilcullen Get Its Power?

The Stratford substation, along with a 110 kV station near Walshestown in Newbridge supply electricity at 38 kV to the substation in Kilcullen. From this station, power is then distributed at a lower 10 kV to pole-mounted transformers (or cabinets in newer housing estates) around the town which finally reduce voltage to 230 V for domestic use. The idea of an electricity grid is to build redundancy into the system so power can find its way around "holes" in the grid (analogous to a fishing net). So if for instance Poulaphouca hydroelectric station becomes non-functional, the transformer station at Stratford is fed from elsewhere. Similarly for the Newbridge station. If the line from Stratford to Kilcullen breaks, or Stratford substation goes out of service, power is still fed to Kilcullen from Newbridge. Eirgrid, who control the transmission network for lines of 110 kV and over, can switch and sync generating stations into and out of the grid as demand rises and falls.
 
This is a map of the high voltage transmission network (high voltage being anything greater than 20 kV)

 
Image courtesy O'Dea Photograph Collection, The National Library of Ireland. Photographer James O'Dea
 

Wednesday, August 07, 2024

Ghostly Events in Kildare

The castle at the back of the Silken Thomas pub and restaurant © Eugene Brennan

 
My grandparents and family were evacuated off the Curragh during WWII and lived in the tower house at the back of the now Silken Thomas pub/inn. As far as I know, this is one of the remaining towers of a more extensive medieval castle, which no longer exists. I remember hearing that skeletons were discovered when foundations were being dug for the cinema, the latter now forming part of the Silken Thomas premises. When we were young we heard stories about poltergeist activity and paranormal events in the castle. According to my father, they had two terrier dogs, which used to bark at blank walls. Beds supposedly also used to move and eventually they had to get the place blessed/exorcised, or so the story goes. I visited Kildare Cathedral a couple of weeks ago and got talking to someone who was checking that there were no people remaining on the grounds before the gates were locked at closing time. I had never been there before, and still haven't seen the inside, although it's primarily a Victorian Gothic Revival structure, only fragments of medieval walls still remaining when it was reconstructed in the 1860s. So not terribly interesting from my point of view and just like the legendary Ship of Theseus or Trigger's Broom. Anyway this person said she had also heard stories about supernatural happenings (although these could have been due to my stories which I had been posting on social media over the years and had just done the rounds!)
 
My grandfather Eugene Brennan in front of the Silken Thomas Castle, circa 1944 © Eugene Brennan
 
I'm sceptical about the paranormal. I think a lot of these type of experiences can be put down to pareidolia (seeing faces in places) which can be either visual or auditory, hallucinations, suggestion, optical illusions etc. Pareidolia is believed to be due to the way our brains are "hardwired" to pick out faces (like the way smartphones can do now) and which in primeval times gave us an edge to be able to spot predators lurking in the undergrowth. I don't believe people necessarily tell lies. They see and experience things they think are supernatural but those things aren't necessarily real. The human mind also creates what we perceive, based on input from our senses. It also interpolates, or "joins the dots", filling in what's not there and the creation in our heads isn't necessarily what's actually "out there". So it can take shortcuts or make guesses.
 

The Chequer Shadow Illusion

 
Here's an example, the chequer shadow illusion. Incredibly, squares marked A and B are the same shade of grey, but influenced by the variation of shades around them. If you don't believe me, Google "Chequer shadow illusion" and download the image. Cut out the squares in your favourite photo editor and paste the pieces onto a white background. Alternatively, use the eyedropper tool to sample the RGB components.


 
 
The Chequer Shadow Illusion. Squares marked "A" and "B" are the same shade of grey. Image attribution: Edward H. Adelson, CC BY-SA 4.0 via Wikimedia Commons. https://creativecommons.org/licenses/by-sa/4.0/

 
 
Image attribution: Edward H. Adelson, CC BY-SA 4.0 via Wikimedia Commons. (Image edited by Eugene Brennan) https://creativecommons.org/licenses/by-sa/4.0/


 
What do you think? Is the paranormal "real"?
 
Maybe my father made up the stories to entertain us? My grandfather served in the British Army in WWI and although he didn't experience trench warfare (he was in the army service corps or ASC), he had vertigo and it's possible he was also shell shocked. Maybe that was responsible for the seeming movement of beds or other furniture. All those involved are dead now, so we'll never know. The castle was last occupied in 1996.

Thursday, August 01, 2024

The Power Stations of Dublin Bay

Poolbeg Power Station circa 1997 © Eugene Brennan

 
You may have heard on the news this morning that the two red and white smokestacks of the Poolbeg Power Station at Ringsend in Dublin are going to be painted and the concrete in the structures has been checked and is in good condition. However the future of the Poolbeg chimneys has yet to be decided. The structures are iconic, being one of the landmarks visible when flying into Dublin and also often shown in wide shots in TV dramas set in the city. Construction of the two chimneys was completed in 1971 and 1978 and according to the ESB media centre, the smokestacks haven't been used for 15 years since the oil fired power station was decommissioned and upgraded to burn gas. 
 
A photo from circa 1997. The former 18th century Pigeon House Hotel is centre of picture with brick Pigeon House Power Station behind it © Eugene Brennan

 
I worked in the "Powerhouse" from 1994 to 1998, a Bolton Trust funded enterprise centre for fledgling start-up companies, located at the foot of the chimneys. At that stage, they belched out white and yellow fumes from the burning of oil, the smoke drifting most days out over the Irish Sea. The area has been in use for various purposes over 200 years and a lot of the land was reclaimed from the sea. The mouth of the River Liffey was originally a mudflat and to improve ship navigation, the Great South Wall was built, which created a narrower and deeper river channel. By confining the river between the North and South Walls, this made it less spread out, increasing flow over a narrower width and causing the riverbed to become scoured naturally as the tide went out. Piles were driven in 1715 and major construction of the wall started in 1717 and eventually finished in 1795. Several paintings from the time showed a causeway leading out to the wall, although this has widened since due to reclamation. The area then became a fort, built from 1814 onwards when there was a threat of a Napoleonic invasion.
 
The Pigeon House Fort. Illustration courtesy The National Library of Ireland.

 
The now ESB-owned Powerhouse building I worked in was originally the Pigeon House Hotel, built in 1793. Alongside the structure is an old dock where sailing ships would have berthed. When the Pigeon House Fort was built, the hotel was repurposed and used as officers quarters. In 1902, the first power station in Dublin was built on the site, the coal fired Pigeon House Power Station. This is a brick building which appeared in a Boyzone video and also the drama, Dublin Murders. It was decommissioned in 1976. Ringsend Power Station, located near the roundabout for the East Link Toll Bridge at Irishtown was another coal fired station, commissioned in 1955-56 and demolished in the noughties to make way for the new ESB Dublin Bay Power Plant. Also located in the area is the Ringsend Energy to Waste Facility which processes 600,000 tonnes of residual solid waste annually and generates approximately 60 MW of power.
 
You may remember the Pigeon House Hotel being used as the setting for the drama series Taken Down, about asylum seekers living in a direct provision centre..
 
References:

Ominous Cloud Formations

© Eugene Brennan

Some ominous mammatus-like clouds (often associated with thunderstorms) from October 2004. They were actually this colour. The billowing on the underside is caused by hail in suspension, being continually circulated by strong updraughts. Hail can move upwards and downwards, ice accumulating like the layers of the skin of an onion on each pass so that the stones can potentially grow to great size.

Jack-Arch Bridge at Grangecon

Engineering infrastructure and trains always fascinate me. On the way back from Athy on the bike yesterday, I passed over this bridge across the old Tullow line near Grangecon (just up the road from the gate lodge for Ballynure House). It's always well maintained and seems to have had a paint job. This is a jack-arch bridge that uses masonry arches abutted by girders to support the deck above. The line was closed to passenger traffic in 1949 and was used for carrying livestock up until 1952. The last passengers carried on the line were in 1957 and 1959 when there were two IRRS (Irish Railway Record Society) excursions.

© Eugene Brennan


© Eugene Brennan
© Eugene Brennan

© Eugene Brennan

© Eugene Brennan