A Topic of Epic Proportion(ing)

For me, the best way to build is to have an end goal in mind. Putting bricks together is great and all, don’t get me wrong. But if you don’t know where you want to end up, how do you expect to get off on the right foot?

That said, there should be some thought that goes into a model before the building process is begun. I usually start a model with extensive research on the prototype. For the purpose of this article, the example model will be a Pennsylvania Railroad BM70m baggage-mail car.

BM70m car no. 6565, a match to my model, albeit riding on different trucks. http://s83.photobucket.com/user/pcarrell/media/Prototype%20Train%20Photos/8-16-071.jpg.html

The first step is to choose a scale to model in. This will set the standard for all scale measurements later on. A very widely accepted scale equates 8 studs to 10 feet, and is used be several LUG’s and individuals, including PennLUG and myself. The equivalence comes from most North American trains are 10 feet wide, and most trains are modelled as 8 studs in width. Using this scale, all measurements on the model will be done in studs, including height, where as many people commonly measure height in bricks. After selecting a scaling standard, find the dimensions of the prototype. There are hundreds of online resources where you can find scale drawings of railroad equipment of all types. Scale drawings are the best way to find dimensions. After all, why wouldn’t you trust the information coming from the original diagrams?

The original scale drawing of the BM70m, straight from the Pennsylvania Railroad. http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=bm70m.gif&sel=baggmail&sz=sm&fr=

In this diagram, the values for length, width, and height are included. Perfect! Now, to convert those values into the correct stud equivalent. This is accomplished using simple cross-multiplication:

The left fraction is your scaling standard. In our case, 8 studs to 10 feet. The right fraction is the conversion to scale stud length. So, in the case of the BM70m, we have:

Here, 74.7525 feet is the length of the car taken from the diagram. This is the number you would replace to find another length. X studs is the unknown length of your model, which is what you are trying to find. Solving for X yields:

Rounding up, we get X = 60 studs. There you have it! Sticking to the 8 studs to 10 feet standard, the BM70m should be 60 studs long. Using this same method, you would then continue to find the rest of the necessary dimensions: 7.875 studs wide (rounded up to 8 studs) and 11.23 studs high, or roughly 28 plates. Remember to have correct units, or else the final number will be incorrect.

My model of the BM70m.

Now you have constrains to operate and build within, and a good starting point for your model. Of course, all of this is relevant. Adding an extra stud or two in length or an extra plate in height will not make or break the model as a whole. My BM70m is 62 studs long. Adding some extra length allowed me to space the windows and doors out properly, so they do not appear to be too close together.

Building to a standard keeps your models scaled well and well-proportioned, and therefore they won’t look awkward when placed next to each other. I hope this article will help shed some new light on LEGO train modeling.

Thanks for reading and happy building!

5 thoughts on “A Topic of Epic Proportion(ing)”

  1. Great article, however, a bit difficult for people from across the pond who tend to use the metric system 😉 Therefore my question: to which scale does 8 studs : 10 feet most closely resemble?

    For example, when building 8 wide for European equipment, we Europeans tend to use something around 1:45 scale or 1:50 scale, due to the same reasons as you just wrote; the width of cars and loco’s. Now I know the European loading gauge is slimmer* than the North American one, but by how much?

    I’m also asking because of my own agenda; at the moment I’m in the process of building one of the few European loco’s that has been able to ‘bridge the gap’ between Europe and the US, the X996, one of the testbed locomotives that Amtrak tested for the replacement of the E60. (In the end they chose the X995 which ended up becoming the AEM7, but this thing is far more brutal than those swedish meatballs / toasters ever were.) It’s interesting to note that this is a fully french locomotive (the CC 21002 to be more precise) that just got some extra bits attached to it to adhere to US crash standards. For the moment, I’m planning on building this loco in 1:45 scale, just like my other European loco’s. However, since this thing will have to be able to pull heritage and amfleet equipment -which I will need to build as well-, for the first time for me the two will interact. At the moment this for example means that a amfleet car would be roughly 9 wide, and not 8.

    *Every European country typically has their own specific loading gauge, coming back from the days before the car was invented. However, I think there are four major loading gauges: UK (slimmest), continental Europe for normal gauge (Netherlands, France, Germany, Italy etc), continental Europe for broad gauge (Spain, Portugal) and Eastern Europe for broad gauge (former states of the Soviet Union, including the Baltics).

    1. 8 studs to 10 feet is approximately 1:47. This is close to USA O Scale (or O gauge), which is 1:48. In the Victorian Railways L Gauge Modellers (Melbourne, Australia), we build in European O scale, which is 1:45. Given the limited resolution of LEGO, the differences in these scales is negligible.

  2. I use a partially transparent checkerboard in Powerpoint to help with scaling. You can see an example here:
    A tool like this means you don’t have to recalculate every stud dimension. You do the calculation once for the length, then scale the original diagram to match the stud length (making sure you maintain the aspect ratio of the diagram). Then you can use the checkerboard to easily estimate the stud dimensions for any feature of the prototype.

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