Recently on the 7mmAusmodelling Yahoo! Group there was an exchange of views on track and wheel standards and how these should be communicated to Australian O-scale modellers. The question was specifically directed at modellers who model standard gauge and who are members of the Aus7 Modellers Group. Before I go any further I should declare my interest: I am the moderator of the above mentioned Yahoo! group and the President of the Aus7 Modellers Group. A couple of modellers who do not work in the same gauge or prototype as many of the members of these groups asked the quite valid question: why isn’t there a published set of standards for those working in 1:43.5 and who model an Australian prototype that address some of the basic questions they might have about things like curve radii or coupler height? Well the simple answer is that there is a set of published standards and they are available when you join the Southern Cross Model Railway Association. While these standards are quite valid it could be said that they could do with a bit of updating and I have to be honest, I haven’t consulted them in years. The reason is that I already know what they contain and the tools and techniques I use conform to the published standards and those they are primarily derived from: namely the UK Finescale standards for 7mm modellers which are readily available to members of the Gaguge-O Guild. I am a member of both of these organisations.

The questions that arose from this debate were: what is the minimum radius curve any particular locomotive will go around and what height should couplers be set at for modellers who model the NSWGR and work in 1:43.5. Neither of these critical questions is answered by the available standards from either of the above organisations. The final and again equally valid question posed was: if the available standards don’t answer these questions why doesn’t the Aus7 Modellers Group do something about it? For me there is one very simple reason why the Aus7 Modellers Group hasn’t set about establishing standardised answers to these questions: the GOG has 6000 members and is into its 6th decade of existence, the Aus7 Modellers Group has just turned 10 and we have just over 100 members. Time and resources are a factor.

I occasionally get asked by a new entrant into the scale what the minimum radius of the curves they should use on their layouts. The simple answer is whatever radius your locomotives will go round. I know this doesn’t really answer the question but I would contend that there is no one answer to this sort of question when you consider the huge range of different locomotives and rolling stock available, to say nothing of the varying level of skill brought to the hobby by any particular modeller. If I put on a web site somewhere that the minimum radius that should be used on a layout is X, along would come half a dozen modellers ready to declare that they followed said advice only to discover that such large curves were a huge waste of precious layout room space. Alternatively another group would appear saying that they had built their layout to the same curves and nothing they own will run around such tight radii! Both would declare that Hodges is a dill! And they would be correct.

Quite a number of years ago I corresponded with a manufacturer about what type of wheels should go under a locomotive kit he was producing. I was adamant that whatever the source of the wheels that they should conform to the FS standards as published by the GOG and the SCRMA. A few years later I was accosted by a rather large and fairly irate individual who remonstrated with me that I was a dope for insisting it be produced with FS wheels because his loco, derived from the kit, wouldn’t traverse an Atlas switch. My response to his accusations of my evident stupidity was to patiently explain that Atlas points are made for a different scale and with the commercial eye on essentially a mass, toy market and not a scale modelling market. To produce a locomotive that is designed for a scale modelling market with wheels that conformed to a set of fairly coarse toy standards (if calling them this isn’t a misnomer in itself) would be a real mistake. I don’t think he was convinced but it taught me the lesson that people get very passionate about these things, even if when the topic is raised, they seem completely uninterested. All he wanted to know was why I’d provided an opinion to the manufacturer that prevented his loco working with a particular commercial track component: he wasn’t interested in the finer points of track and wheel standards. The point is that the necessary track and wheel standards do exist and are readily available if the modeller wishes to access them.

I feel that the late UK modeller David Jenkinson, one of my modelling heroes and sources of inspiration, has probably set out the clearest explanation of what attitude the 1:43.5 finescale modeller should bring to the vexed issue of curve radii on their layouts in his series of articles in Model Railway Journal (issue 85, 86 and 88 et al) called The Last Great Project. Of curve radii he wrote:

“Obvious though it may seem, it is vital that you know the minimum curve around which all your models will run…You can do it the practical way by setting out full size curves on a spare piece of baseboard material then trying out the model. But my preferred alternative is to decide the minimum curve from the outset and make all models capable of traversing it…my usual minimum radius is 5’3″ [approximately 1545mm]…I ease this out to 6′ [1800mm] in cases such as the above mentioned point complex [he’s referring to point work that didn’t operate the way he had hoped]. For the record this radius has never caused me problems and it has the useful benefit of saving about 18″ of width for a full semi-circle of plain track compared with the more customary recommendation of 6ft for gauge O.”

I couldn’t have said it better myself so I haven’t tried. There is no one minimum radius of curve that every modeller should or must conform to: as Jenkinson suggests, the radius of the curves you use should be determined first and then you modify and build your stock to traverse these curves. However it is pretty clear that going much below his suggestion of 1600mm is starting to ask for trouble.However 5’3″ (1600mm) is more than likely the dimension I will use as the minimum radius on my new layout and I will use precisely his suggested method of getting my stockj to go round these curves: a totally practical road tested method of getting things to work. Not a theoretical set of “standards” or “recommendations” that no one really uses and far less likely to get my head punched in 🙂

Whether your stock will go round such curves is determined by a range of factors, not the least of these being the way you set up your couplers and buffers. While couplers and buffers are a topic that probably need to be dealt with on their own I might pass on what I have settled on as my own standard for coupler height. Height alone is not the only determinant in the application of standards to our modelling but it is the most frequently discussed topic among modeller new to the scale. I use a simple standard for the height at which I set my couplers: the NSWR set the centre of their auto couplers at 2’11” above rail head  height so this is the height I work to. This prototype height scales out at approximately 20.4mm in 1:43.5. A 7mm scale inch is .583mm and to get the height you multiply it by the number of inches: .583mm X 35 inches = 20.4. I determine the centre height of the coupler by use of woodworking saw height gauge and a simple wooden platform with a short length of flex track with a small wooden block at one end of the track the top surface of which sits at rail head height. I sit the gauge on the block and set the pointer of the gauge at 20.4mm and then place the model I’m working on next to this. Adjustments are made until I get the wagon or loco to the height I need. I did just this on the current BWH project I’m working on. No matter how much I tried I couldn’t get the wagon high enough to allow the centre height to match 20.4mm. So over the weekend I clamped the wagon in my mill and shaved 2mm from the top of the coupler platform on the wagon.

The way the wagon is clamped may seem a little over the top but I need to keep the wagon still while the mill head does its work. Usually I would have done such work well before I got to this stage but the wagon was already partially complete when I bought it.

The way the wagon is clamped may seem a little over the top but I need to keep the wagon still while the mill head does its work. Usually I would have done such work well before I got to this stage but the wagon was already partially complete when I bought it.

You don’t need a mill to carry out such adjustments but the reason I acquired it was so that jobs like this were easy. It took about 10 minutes to complete this task and the coupler now rides at the perfect height.


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