A world class industrial heritage site

Museum Operations

This is a blog about the day to day operations at the Gasworks Museum site

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Good News – the Forge is back in business


“Nothing works at the Gasworks” is no  more! Not only do we have steam thanks to the great efforts of Tom and John and the operations team in reinstating the new boiler, but also Peter Mason our blacksmith has the forge up and running having had to repair a leak in the tuyere  (the air pipe coming directly in contact with the fire on the bellows of the forge).  If you want to find more out about the operations of a Forge check out this site http://www.beautifuliron.com/forge.htm.

Peter is presently cleaning up old equipment by an annealing process where the steel is quenched (rapidly cooled)  in oil.



Rust, Restoration and Routine.

Tuesday 14th January, work day with plenty of action. First, recent high winds and generally inclement weather have paid their usual price, and rusty and dirty machines awaited us today. Suffice to say we “rolled up our sleeves” and got on with the clean up. We are dammed if we do and dammed if we don’t with our cleaning regime: required to oil to prevent rust, but oiled surfaces attract dust and dirt. Tom and John discussed this and decided, with all due consideration, balancing machine conservation with satisfactory exhibit presentation to the public, continuing this cleaning regime is still the best option. The only problem being its very labour intensive, and places a large responsibility on the small operations team.

Mack and Tom continued work on restoration of the no2 exhauster, Stan continued with the weirs pumps restoration, while Bob H. and John got stuck into the cleaning duties.

Tuesday, (along with Wednesday), we hosted the University Hands on Science – Gasworks Snacks program. The visiting group showed the usual enthusiasm, and we look forward to continuing our community educational efforts. A highlight was Tom’s model steam traction engine, and the students showed much interest. Notable was the very appropriate questions asked by our younger visitors who have never experienced the “steam age” as us older generation have.

A.J. Grant limited, delivered to us a collection of iron work tools, originating from the Green Island Cement Works. These tools are destined to enhance Peter’s forge operation and exhibit.

The finger mark on the big exhauster coupling indicates the “overall condition” of all the exhibits – before cleaning.


Before and after, on the big exhauster flywheel 


Little engine, big engine. Tom’s model steam traction engine. 


 The selection of iron working tool received today.


 Cleaning in action, mops, brushes, shovels, rags and jet fuel (yes – jet fuel) used in the cleaning process.


Mack and Tom work on the no2 exhauster restoration.


 Tom addresses Hands on Science students in the engine house.

Dynamos, static and otherwise (ref – our motor-gen set display)

Sunday 12th January open day with just six adults and five children visitors. However three of the kids seemed like thirty – literally running from exhibit to exhibit – “mister can we touch this?, can we touch that?, can we play with this?, can we open that? why is that chained up?” these kids kept Tom and Ann fully occupied. The moral of this story is: we have a great product – lets promote it. (And yes! you can touch it)
Meanwhile, Peter Mason, our Blacksmith volunteer continued repairs and set up on the forge.

Week one 2014

While the last Sunday in 2013 “went with a bang” the first in 2014 was “more of a pop” – seven visitors were recorded.

Tuesday’s work day was spent with Operations volunteers catching up after the holiday break and generally “chewing the fat”, therefore little “work” was accomplished. We did however, commit Tom to support the FOH folk on the first and third Sundays, while John would “do” the second and forth Sundays. Mack, Keith, and the others will assist as and when available. We are guessing at this time, but we may have the boiler back in action late March or April. We are pleased to report Tuesday’s (today)visitor numbers were 6/7th of the previous Sunday.

Bill C. has generously shared his information on the gasworks railway siding, and this has been posted for general and public view on our alternate website. ( The IhdunedinNZ web site layout has been modified to accommodate the increasing Gasworks info – and hopefully becoming a useful resource for our volunteers – please check it out.)  http://ihdunedinnz.weebly.com/

Is half the story —

Motivated by a positive reception to my last Water Gas infoblog, and while personally expanding the detail today, it became clear I should have included this additional information, now provided here.


 On the Braemar street wall, the water gas main exited the building at the high level and connected to the pipe up-stand visible directly below the window. This in turn connected to the water gas holder. The pipe section partially visible front-right of picture is a section of the underground connection to the holder recovered during site work at the current gas holder legs.

This site, on the Western wall of the Engine house extension, once sported a venturi type flow meter, measuring the Water gas flow into the foul main.


This pipe (circled)  on the northern wall of the Anderson room, is all that is left of the steam connection to the water gas plant.



Dunedin’s Water Gas.

Technical descriptions of water gas plant can be found in the GWM library, and on the internet. A couple of information panels are also provided in the Donkin annex of the museum. Therefore, detailed technical description is not reproduced here. Never-the-less a brief summary of the technology is necessary, and included, to enhance understanding of this blog. Water gas production required the interaction between water (steam) and carbon (coke) to reduce water into Hydrogen and (flammable) Carbon Monoxide. If conditions were not correct, (inflammable) Carbon Dioxide could be produced and this was not good! A secondary hydrocarbon enhancement stage was generally provided to produce an acceptable Calorific Value (CV). Production was by a batch system, with gas produced during  a “run” cycle, followed by a recharging cycle. As such, water gas systems required some sort of buffer or storage facility, in Dunedin’s case, this was the water gas holder situated near the current gas holder legs.

Known under various names, water gas was produced at the Dunedin Gasworks site, in two different eras. The first plant was dismantled and shipped north to Napier to assist the town recover from the disastrous 1931 earthquake. It was never returned. A second production plant was installed in 1952, and continued until the cessation of coal gas production. Early plant was manually controlled with coloured time-controlled indicators advising the operator which appropriately coloured valve or handle to adjust. Later models were automatic.

The Water gas plant was situated approximately where the traction engine shed sits today. As previously noted, the water gas holder was sited close to, (but smaller than) today’s museum gas holder legs. Parts remaining at the museum today are the water gas main, from the production plant to (almost) the water gas holder, a small portion of the underground connection to the gas holder, and the connection to the foul main where the water gas was mixed with coal gas for filtering, storage and distribution.

The yellow pipe is the water-gas main from the production plant (previously in the distance) to the water-gas holder (previously behind the camera)


 The water-gas connection to the foul main (circled). Long gone pipework connected this valve to the water-gas holder. 

Liquid Assets

Open day today. A “trickle” of visitors, an improvement on the “sprinkle” we have been getting recently, and showers of rain. Sian, Phil and Ann on FOH were supported by Mack and John from Operations. Without the boiler and machines to operate, Mack and John cleaned up the mess left after moving the governor last week. While still work-in-progress, but consistent with current thinking, we have left a lot of open space in the Engine House reception area. It is now more easy to visualise the Donkin Engine House extension  without the old desk and and the RSJ partitions. (Removal of these items is a sound plan, and look forward to it happening – Ed)

 The re-jigged entrance – Lots of open space.



Many hands make –

Work day today, and for a short while we had twelve arms, hands, and feet on deck, but must add, only four pair available for heavy work. Taking advantage of the four-on-deck we moved the “indoor governor” and the associated valve to a temporary position in the main Engine House hall. This is work-in-progress with setting up and cleaning up still required over the next few days to be followed in due course by appropriate treatment of the valve body.

Two visitors from Scotland today and John took time out to make a fuss of them. They spent over an hour at the museum, returning very positive feedback and leaving a generous donation.. They had heard about the us by word-of-mouth, but on their enquiry, the (Mercure hotel) reception had no knowledge of our operation. Being fair to the Mercure, the receptionist “looked us up” and correctly directed the visitors – Thanks Mercure.

The governor and valve relocated to the main Engine House hall today. Work-in-progress, also the wall behind could do with some TLC.


It gets better folks

Open day today. Just a sprinkling of visitors, but all unanimous our attraction is of high quality and of much interest. (“wait until you see us steaming” – Ed)

We need a bloodhound!

Observant volunteers and visitors may have noticed the unusual markings on the floor just inside the internal door to the main Engine House. These represent the position of a long gone steam-engine driven electrical machine. The original purpose of the machine is not known by the writer, or even whether it was an alternator or a generator. Some local legend indicates the machine, at times, exported electricity to the DCC tram network, suggesting it was a DC machine. However this has not been confirmed.

More certain is that the machine was sold to Downers Ltd for use on construction of the Lyttleton tunnel.

Does it still exist, and if so where is it now?

Wouldn’t it be nice (song title pun not intended) to locate this machine and return it to its rightful position, perhaps as a swap for the Sp8s boiler or a steam winch!

Anyone interested in taking up this cause? Could we make it a project?

Being of the electrical persuasion and declaring a total bias in favour of progressing, but with research not my “thing”, I would happily assist any researchers to advance this matter – John

The outline on the floor indicates the position of the engine and the electrical machine.

 Behind the left hand exhauster – now the Reader – can be seen a very interesting steam engine and its associated electrical machine.


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