Saturday 17 March 2012

Australian HO broad gauge

At the Sandown Model Railway Exhibition last weekend in Melbourne, Bendigo Rail Models (distributed by Auscision) released the Victorian Railways flat top T class diesel locomotive in HO scale. The model is available in a range of prototype numbers and versions according to three different time periods - see info here.

The flat top T class had also been previously announced by Austrains. I imagine Austrains will release a statement to the market advising what their intentions are for their model; not necessarily in response to the new model from Bendigo, but because of some speculation already circling in news groups. Austrains had previously released models of the later versions of the T class (as had Powerline). The Victorian Railways T class is therefore a popular class of locomotive.

The T class, however, was predominantly a locomotive used on the broad gauge (5' 3") of the Victorian Railways. This list of VR T class diesels indicates that nearly all the T class diesels, certainly in the early years to the 1970s, were broad gauge locos.

Whilst my Australian model railway interests are largely NSW, I also have an interest in Victorian Railways and also the Commonwealth/South Australian railways. As such, the issue of track gauge always stands out. In Victoria, the broad gauge dominated for most of its history while in South Australia, all three conventional track gauges (3' 6", 4' 8 1/2" and 5' 3") were used. In NSW, the standard gauge (4' 8 1/2") was the norm. In HO scale, the 16.5mm gauge reflects the standard gauge track of the prototype.

But herein is a dilemma for Victorian modellers. As much of their railway was (and to a lesser extent remains today) on the broad gauge, what is to be done about the HO scale track gauge? The standard gauge track in HO scale (16.5mm) will be too narrow for modellers of the broad gauge prototype. The answer, to date, has been the production of broad gauge models with wheel spacings to sit on HO scale standard gauge track. This is the so-called scale track dilemma most notorious in British model railway circles where the OO scale (4mm) models are running around on HO scale (3.5mm to the foot) track.

In Britain, the compromise is readily excepted. A shift to HO scale from OO scale remains unlikely; certainly from the main model railway manufacturers servicing that market. From time to time the issue receives some emotional comment and correspondence in the British model railway press. There are many who are happy to stay with the 4mm scale motive power and rolling stock on HO scale track.

In Australia, the debate about broad gauge track has received less publicity which may also reflect less interest. On the other hand, Australian prototype modellers modelling narrow gauge (3' 6") in HO scale are quite aware of the scale-gauge issue and work accordingly using 12mm track (HOn3.5). Some modellers prefer to model the Australian narrow gauge railways in S scale (3/16" to the foot) using 16.5mm track (for example in Western Australia and in Queensland). Modellers of Australian broad gauge railways (mainly Victorian Railways) seem quite happy to ignore the scale-track gauge issue (and here I willingly admit to being one of them).

I therefore really have two questions to ask:

Firstly, is it necessary (desired?) to model the Victorian Railways broad gauge in HO scale using the wider scale track (18.37mm) instead of 16.5mm?

And, should manufacturers of model railway equipment for broad gauge prototypes like Victorian Railways ensure that a supply of accurately gauged locos and rolling stock are available for sale? Or, alternatively, produce models that at least can be be readily converted to the broader gauge than the usual 16.5mm gauge (using spacers is what I understand happens in the UK).

I am interested in what people think about this issue so please feel free to comment.


  1. I am not sure the RTR modellers of VR, or SAR would welcome such a change. It has been a long time since they have managed to obtain manufacturer support for their prototype, and to complicate the manufacture of these items by offering multiple guage offerings will not lead to any more sales. Indeed, it would push up the price of the RTR models. Of course, the modern day modeller need not worry, as many of the broad guage lines are standard gauged now, and bogie exchange is commonplace for diesls and wagons.

    However, the last VR steam engines (eg J and R) were designed to be standard guaged - so I do not think one needs worry about a compromise too greatly. And that is why I won't be regauging any of my VR RTR diesels, PSM steamers, or DJH kits anytime soon.

    You mention about the UK scene, with EM 18.2 mm gauge. (This is still 0.63mm too narrow for the exact 18.83 P4 standard, but lets not go there)There are a number of loco kit manufacturers who do provide alternate spacers for the frames, and longer axles for those modellers who want to be different. A number of manufacturers also provide correctly guaged track and pointwork. So, with alternate axles being readily available for the RTR wagons, building a layout in EM is not that hard in comparision with an OO/16.5 layout. But, as this standard is across the entire UK OO market, coupled with far more modellers out there, limited manufacturer support is available. And this makes the difference.

    With regard to Aussie models, there are some within AMRA Vic who are scratchbuilding, and kit bashing for a wider gauge on HO scale. However, I can only recall ever seeing one exhibition layout built to this wider gauge. I suspect that those modellers are simply trying to be different, and challenging their own skills. Technically, some things should be easy enough. A bogie point-to-point axle length of 26 mm should be long enough to support RP25/88 wheelsets at 18.2mm gauge, as these are skinnier than the often supplied RP25/110 wheels. One could potentially also have correctly gauged geared axles for the diesels made to suit without having the extensive bogie modifications that QR modellers go through to narrow commercial power bogies.

    So, in summary, I think that if one wants HO models to run on a wider gauge than the RTR 16.5, all power to them. But please, keep this as a niche area, and not mainstream. It is bad enough today when in O scale, commercial NSWGR models are using 7mm (1:43.5), and VR are using 1:48 scale to simulate the gauge better. Seems we are still perpetuating the gauge problem.

  2. Brad,

    I looked into this issue 20 years or more ago and I think the fundamental issue is one of what you want to get our of your modelling. There are clearly different ways to go.

    If your personal preference is for fine scale then the gauge issue is one that needs consideration. To be consistent with fine detailing of other parts of the model a wider gauge should be adopted.

    The reality is that most of the available rolling-stock is fairly easily adapted to the wider gauge simply by substituting wider wheel sets. You would have to hand lay your track but many people do that already. The difficulty lies with steam locos as clearances are very tight.

    Another blogger, Jules Watson, is working on a SEM J class conversion.

    For me, being time and motivation poor, RTR and kits to HO gauge are easier because it is quicker.

    This is not an issue of competing scales such as the absurd divide between NSW and Vic models over what is O scale.

  3. Raising the general VR/SAR modellers' consciousness about the gauge issue of HO scale models is welcome, but I agree with RobN that, at the moment, they would not welcome wider gauge alternatives for mainstream modellers. Yes, it is a niche area. For me, personally, it was the natural outcome of changing to P87 standards - why correct the wheel profile and track standards without correcting the gauge as well? There are, however, a growing number of P87 broad gauge modellers in SA and Victoria, and regauging models and laying our own track is par for the course.

    Just to add to the narrow gauge story, 10.5mm is also a common gauge SAR HO narrow gaugers use because the spacing of the rails in dual gauge trackage, where 16.5mm is used as the 'broad' gauge, looks more prototypical than 12mm/16.5mm dual gauge track.

    With more exposure of the model broad gauge inconsistency, who knows where it will eventually lead?

    Ross Hurley

  4. a lot comes down to what is available. some VR HO broad gaugers prefer the UK 'EM' 18.2mm gauge and i can see why ... the brits have this habit of supporting weird finescale options and it often makes things a bit easier.

    i like TT scale. i like broad gauge too. if i wanted to do TT broad gauge at 1:120, there is a gauge available that is more or less suitable -13.5mm from the 3mm society, or you could just go exact 5'3" 1600mm /120 = 13.3mm. however, unless you wanted to invent your own standard and make everything yourself, modelling finescale 1:120 entails adopting P87 standards for code 64 wheels, using expensive NWSL wheels and either having spoked wheels milled (NWSL don't do them) or reducing SEM 7.6mm code 88 spoke wheels to code 64.

    you couldn't use standard code 88 wheels gauged to broad gauge on TT axles ... and what would be the point in doing the correct gauge but using coarse wheels?

    so 1:120 is a headache. i'm not a model engineer. i've been advised many times that P87 standards are inadvisable unless you are. more power to those who can use them; but i'm not in that club.

    however, if you use some of the 3mm society range of .0069" finescale wheels, 8mm dia for wagons, 9/9.2mm for locos and their gauge - 14.2mm - and finescale standards, a scale of 1:113 suggests itself as being a workable finescale option. and there are bogies available and 3mm society underframes too.

    so a lot works out right ... real life australian railways are scaled about halfway between US/continental and british, so it perhaps isn't surprising that a modelling scale halfway between the two works out.

  5. The majority rules, and it would seem as though the majority want ready to run or kit built models so they can get on with playing trains. Perhaps they're cretons. I'm not sure I care.

    I like scratchbuilding (including my own track), but although I'm very interested in a possible future broad gauge layout to fine scale standards my building interests lie more in art and history, so I'm happy to position myself more flexibly (viz. allowing ready to run, kit built and scratchbuilt stock on my layout). We all build to the detail we want to, and as long as we do this we should remain happy (at least I do!).

    The net result is that for such a small market as Australia it is not commercially viable to appeal to anything but the most mainstream of tastes. Again, this doesn't bother me. If I want to build in P87 broad gauge standards I will.

    In the meantime I keep happily researching and building my pre-1918 VR models for their beauty - but not for accuracy in the strictest sense.

  6. If I was worried about true prototype representation, I would ensure I had a good 335 metre run (30 scale kilometres) between my rural stations. You don't have a 300 metre layout?! How can you be so unprototypical!
    I don't even understand EM - 0.5mm is just not worth worrying about compared to the other compromises we make.