NGG16.com

A Garratt In Miniature

Monthly Archives: January 2010

An update on the Jigsaw

A few up to date progress images of where I am in the build (both bogies are progressed to this point)…

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From this point on, the blog goes real time

All the previous posts are kind of a catchup of progress so far. Work started on the loco in mid/late last year and with the blog only just started, I thought i’d better catchup first! So, everything from here on will be in real time. I only get about 1 or 2 days a week on the build, so its going to take a while before an NGG16 roles out of the workshop.

Cylinders first

Unlike my old Hunslet, I wanted to convince myself that the project would work when completed. So, I made an early decision to build the cylinders first. Initially, thought turned to wood patterns and castings, but after reviewing this Big Boy website, I decided that I would fabricate the cylinders from steel with bronze liners. In a similar style to the big boy, steam passages were bored, milled and drilled and then a valve/main cylinder set was silver soldered together as shown below…

Ultimately, when paired with the opposite side and the cylinder end cheeks, it would form the basis of a complete cylinder set for one bogie…

 As the images show above, the cylinder are still in the early days of construction. Work on the liners and end caps are underway. Once complete, the end cheeks will be welded to the bores and the liners and end caps fitted.

It’s like Christmas come early!

After finalizing the basic design of the two bogies, a set of CAD drawings were constructed to get the laser cutting process underway. There’s been a lot of interesting articles in the ME press about laser cutting and slotting pieces together (kinda like a big jigsaw) and I was impressed at how well this seemed to work. So, I jumped on this bandwagon and made the frames as a big jigsaw.

An order was placed with Alsager Precision Engineering for the laser cutting and the project was now heading from paper, via laser, to steel. A few weeks later, the first batch of many was ready for collection…

 

The two main frames (10mm plate), buffer beam, pivot plate and motion bracket/frame stetcher.

Cylinder end cheeks/frame stretcher, cylinder mounting brackets and fly crank.

As you can see, the majority of components are ready to be slotted together to turn the flat 2D into 3D. I’m not going to reveal the frames slotted together quite yet, but lets say they look impressive already. It looks like the jigsaw theory is working well as this sneak peak at the cylinder set shows…

Doing things the easy way

From the start, this project was going to be a mammoth task, with lots of head scratching and hours of wondering. As I have a full set of drawings for the full size locomotive, I had a good start on the construction. Having spent the good part of two months learning TurboCad, work was started on translating the full size drawings to a usable 5″ gauge set. The main reason for using CAD was to enable a bit of cheating on the project!

Some model engineers will cringe at this sort of construction and the use of a laser to cut metal, but when you are presented will hundreds of curves, holes and intricate shapes which need hacksawing, milling and filing – I know what I’d rather do! And besides, the hacksaw I use tends to only cut curved lines, although i’m sure its not operator error!

Once into the swing of TurboCad, I found it a very easy program to use and one i’d recommend. It exports to .dxf, which is a standard drawing format used for laser cutting.

Why an NGG16?

Why not!… You can’t really get much bigger than a narrow gauge Garratt in 5″ gauge and thinking of the long term, I needed a big project to get stuck into – something that would challenge me and allow me to learn new skills along the way.

I’ve had a short list for several years now…

*Welsh Highland Railway, Russell 2-6-2 (Hunslet)
*Tasmanian Railways, K1 Garratt 0-4-0 + 0-4-0 (Beyer Peacock)
*Lynton And Barnstable Railway, Lyn, 2-6-2 (Manning Wardle)

All had their pros and cons, but ultimately, it kept coming back to the NGG16, the elegant and powerful South African 2′ Garratt. For those not familiar with the 16, it’s a 2-6-2 + 2-6-2 Beyer Peacock Garratt, built right here in the Northwest of England in Manchester. Many 16’s can still be seen operating in South Africa and there are currently 3 working example over at the Welsh Highland Railway in Caernarfon. We even have one being restored in my hometown!

In the beginning…

All shiny and new, a works photograph if you wish.

Passing the station at my club track, the Mid Cheshire SME.

I guess it all started many moons ago, when I became involved in model engineering as a hobby. I was probably more inclined to ‘play trains’ at first, although this soon subsided and the prospect of building a loco took my fancy. Not content with building a lawnmower or battery on wheels, there was clearly only one way to go – live steam was calling!

Having always had a leaning towards narrow gauge, the obvious loco of choice would be a quarry Hunslet. Once common as muck in the Welsh valleys, these iconic locos could provide a good size loco in 5″, capable of pulling a few trucks full of happy passengers. The Hunslet took around 10 years to complete, although I did have a 5 year holiday in the middle of construction!

Quite happy in the knowledge that my Hunslet was now fully painted and running well, my thoughts turned to my next project… and here we are!