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DISPLAYING POSTS BY: Matilda Vaughan (2)

1889 tram model

Author
by Matilda Vaughan
Publish date
29 October 2013
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Comments (1)

Matilda swapped a life working as an engineer for a life curating the museum’s historical Engineering collection. She’s very curious about how stuff works, how it’s made and why. If a machine’s got a switch, she’ll definitely flick it.

What do you do when a significant part of our local transport history would make a great addition to a new exhibition, but it no longer exists? Well, you recreate it in miniature, of course.

By 1888, Melbourne was already on its way to an integrated suburban rail transport network, and horse-drawn tramcars mingled with cable tramcars. Tramcars propelled by electric motors were very new and developing rapidly. Overseas commercially-operated installations were powered by either on-board batteries or connections to external underground or overhead electrical wiring. The first electric tram powered by an overhead wire in Australia was demonstrated as a fee paying, passenger-carrying attraction within the grounds of the 1888 Melbourne International Centennial Exhibition.

Men on Melbourne's first electric tram Australia’s first suburban electric tramway service at the Box Hill terminus on opening day, 14 October 1889. Do these passengers look excited about their ride on the latest public transport system in Melbourne?
Source: Doncaster & Templestowe Historical Society (DP0203)

While news reports from the time provide basic information about the tramcar and the exhibit, we couldn’t find any surviving photographs. However images do exist of its later use, in the following year, on the Box Hill-Doncaster Tramway Company’s route. This route ran from Box Hill Railway Station up what is now known as Tram Road, towards the Observation Tower and close to where Doncaster Shoppingtown now stands.

We provided these photographs, supplemented with curatorial research gleaned from historical literature such as newspapers, engineering journals, patents and electric tramcar and street railway technology reviews, to model maker Mark O'Brien. He used this information to prepare a digital model using 3D modelling software, carefully deconstructing parts to suit the manufacturing method.

Man sitting at computer showing a 3D digital model The 3D digital model can be rotated and viewed from all angles, to match the viewers’ perspective to the original photographic image.
Image: Matilda Vaughan
Source: Museum Victoria
 

Then came the real art of the project: translating the digital model into an actual object. The miniature parts were crafted with a blend of traditional model making techniques and additive manufacturing technology (3D printing).

parts of tram model Left: assembly of the tram model parts prior to painting and finishing. Right: the truck (or bogie) construction prior to painting, in the hand of the model maker Mark O'Brien.
Image: Matilda Vaughan
Source: Museum Victoria

parts of tram model Left: detail of conductor base. Right: electric motor, wheels and axle box, 3D printed and finished to resemble metal.
Image: Matilda Vaughan
Source: Museum Victoria
 

Scanning the tram model into the collection system Upon its arrival at the museum, we checked the condition of the tram model, registered it, tagged it and scanned into the Collection Location System for tracking.
Image: Matilda Vaughan
Source: Museum Victoria
 

When the Box Hill tramway closed down, the original tramcar was sold to H.V. McKay’s Sunshine agricultural implements manufacturing plant and stripped of its electric motor and fittings. The tramcar carriage itself became one of the shelter sheds used for workers’ leisure activities in the nearby parklands. It suffered the fate of most wooden objects left out in the weather for years. In the museum environment however, this miniature representation of the tramcar will live on as part of the as part of the state’s permanent Rail Transport Collection, and will be part of the Think Ahead exhibition at Scienceworks from December 2013.

Casting for the Great Melbourne Telescope

Author
by Matilda Vaughan
Publish date
21 December 2012
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Comments (1)

Matilda swapped a life working as an engineer for a life curating the museum’s historical Engineering collection. She’s very curious about how stuff works, how it’s made and why. If a machine’s got a switch, she’ll definitely flick it.

Last week I visited a foundry in Melbourne that was casting a vital component for our restoration of the Great Melbourne Telescope. The original part of the telescope - the declination disc - had been modified and broken at some time in its history and was not repairable.

Great Melbourne Telescope in 1870 The Great Melbourne Telescope in its own house at the Melbourne Observatory, 1870. The red arrow points to the declination disc needing replacement.
Source: Museum Victoria
 

This is the first part of the project to be made by a sand moulding or casting process very similar to that which was used in Ireland in the late 1860s. Our modern part is made from a type of cast iron invented in the 1940s which has magnesium added to give it properties that make it easier to shape. The electric induction furnace, which is used to melt the metal, was developed in the early 20th century.

A couple of weeks ago, Peter made a pattern out of wood for the casting. Tom next used the pattern to form a hollow in a sand mould. This kind of mould is a mixture of washed sand and a binder, made in two halves, and cured to retain its shape once the pattern is removed. The two halves of the mould were then closed, after a pouring spout, flow paths and risers (to allow the metal to flow to and fill all sections of the hollow) were added. Heavy weights on top ensured it remained closed when the metal was poured.

Man working with metal The sparks fly as Bryn takes a sample from the furnace for temperature testing.
Image: Matilda Vaughan
Source: Museum Victoria
 

The pounded earth floor and the filtered light through the open doorways and skylights in the roof of the foundry transported me back in time. It was 7 AM and Bryn had already been awake for hours and the sparking pot of molten metal (spheroidal graphite iron) was his morning's labour. He tested its temperature and composition, turned the knob of the electric induction furnace's control panel, and gave the signal. After the removal of the slag crust, the metal was ready for pouring.

Man pouring molten metal Bryn pours the molten metal into the next mould as Tom looks on. Our filled mould is on the floor behind them.
Image: Matilda Vaughan
Source: Museum Victoria
 

Bryn added the final ingredients and carefully tipped the 1500°C molten metal into the pre-heated ladle. He then transported the ladle to the moulding area and poured it first into our waiting mould, and then onto the other smaller moulds. Being such a large casting, ours needed almost 24 hours to cool down before breaking open the mould.

Sand mould in workshop The lower half of the sand mould, with the casting removed. The sand from the top half is in pieces in the background. The sand will be cleaned and reused, as will the molten scraps of metal.
Image: Matilda Vaughan
Source: Museum Victoria
 

At 6 AM the following morning, Bryn was ready to break open the mould. The weights were removed and the upper part of the mould lifted away. Then the casting itself was lifted into the air and the sand and metal debris removed. It was then transported by the overhead mobile crane to the finishing room, where the hardened parts of the spout, risers and flow paths were ground and knocked off and the surfaces cleaned.

Men with newly cast metal pieces Bryn (left) with the pattern for our declination disc, and Tom (right) with the freshly removed casting. Note the four cylindrical 'risers' at the edge, the pouring pathways (almost like a running person) in the middle and the square shaped pouring spout (head of the running person). These pieces are reused for the next batch of metal.
Image: Matilda Vaughan
Source: Museum Victoria
 

The next step for this part will be heat treatment to 'relax' the metal, followed by the final shaping and machining. It is a rare sight to see this process so close in our urban environment and one of the great aspects to working on restoration projects of this magnitude.

Links:

Great Melbourne Telescope website

Great Melbourne Telescope on Collections Online

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Updates on what's happening at Melbourne Museum, the Immigration Museum, Scienceworks, the Royal Exhibition Building, and beyond.

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