History of Scale Drawings - 1:36 Series
To simplify explanations and calculations, the 1:36 series broke away from the semi-random scales of previous series to be fixed at exactly 24 pixels per foot, or 2 pixels per inch. The scale when printed can therefore be obtained simply by taking the printing image resolution in PPI divided by 2, or a scale of 1:(PPI/2).
The drawings are precise, but the number in the scale is not particularly relevant, since the images can be scaled when printed. The scale is based on the commonly used 72 PPI resolution that was also apparently used to scale drawings at the Railroad Paintshop, but the images are actually 96 PPI by default. When printed at 100%, this works out to a scale of 1:48.
Origins of the 1:36 Series
Although I started the 1:36 series in February 2008, it can trace its origins back much farther.
Back in 2005, when I first started revising (and later completely redrawing) parts of the 1:55 series, the idea crossed my mind of introducing a new drawing size, done at a more easy-to-use scale. At a scale of 16.2 pixels per foot, the 1:55 series was awkward to work with and hard to explain to other artists. I thought of introducing a larger size, such as 20 or 24 pixels per foot, which would allow me to incorporate a higher level of detail. However, with a collection of about 2000 1:55 drawings, the idea of starting from scratch was daunting. Perhaps more importantly, I was not convinced that I could find adequate reference material to draw in a larger scale with sufficient accuracy. After the revised 1:55 drawings of 2005-2006 were positively received by site viewers, I put the idea of a larger series on the back burner.
However, a series of events in late 2007 and early 2008 sowed the seeds for a larger scale. In November 2007, I bought a new camera (Canon Digital Rebel XTi), which started an incredibly frenzy of roster and detail photography. There were also many high-resolution photos becoming available online. With high-resolution reference photos now in abundance, I was running into resolution barriers in 1:55, having to fudge small details that were now clearly visible in photos.
In late February 2008, I received several requests within a period of only a few days that I couldn't provide: larger drawings, vector images or details that were too fine for 1:55. That spontaneously led to the beginning of a new series on February 22, and the completion of the first 1:36 drawing on February 23, 2008.
Above: A nearly-completed view of the first 1:36 drawing, an EMD RM-1, as it appeared on February 23, 2008. A number of corrections and additions were made before it was uploaded, and a few more changes were made in the following weeks. Click here for the final version.
Making the Drawings
There's nothing revolutionary about the making of the 1:36 drawings. I retained the method I had used for all drawings up to that point: editing the images directly as GIF files in MS Paint. Although the added detail took a bit more time to decipher and draw, the scale (24 pixels per foot) was very easy to work with and ultimately more satisfying than previous scales.
In addition to including added detail, I made dimensional accuracy a key priority starting with the 1:36 series. This went beyond the major dimensions, like truck centers and wheelbase, length over the pilots, length over the coupler pulling faces and height over the cab. I started to follow as many other listed dimensions as I could find, whether from other drawings or in discussion forums—things like frame height, cab length, stanchion spacing, door height, fan diameter and so on. The availability of these dimensions partly determined which models I drew first, as I could then derive other models from shared components.
Most often I calculated the smaller dimensions from photos, many of which I've taken myself specifically for that purpose. With the 1:36 series, I began to measure everything—the width of a wheel bearing; the size of door latches and hinges; the diameter of the sand lines, motor cables, air hoses and handrails; the number and position bolts around a grill or panel, and so on. Common parts incorporated into many different drawings were given special attention. I drew couplers based on photos and patent diagrams, separate traction motors (with the truck frame layered on top), and snowplows traced from modified direct side views. The best part was that many of these details weree identical between a large range of different models, so it really only took time to draw them in the first place.
Accuracy based on photos or measurements can also only be taken to a certain point before inconsistencies in the prototype begin to surface. Wheels decrease in diameter over time, springs gradually compress, modifications and repairs are made, initial construction may not have been exact—and when inconsistencies like these appear, I take as-built specifications (if available) or else a median value from several measurements.
Also, for all the care taken, there are details that will just be missed. Photos don't always provide a perfect angle and require some interpretation—and I also have a tendancy to forget the last small details. For these I often rely on the help of site viewers.