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Hey EB, it's time for another train MOC! Today's locomotive is the EMD Model 40, a small industrial switcher made in very limited quantity in the early 40s. The model is approximately 1:48 scale, contains about 360 parts, and weighs about 360 grams. Much like my PRR A6b, this locomotive is an oddity among American locomotives in that it only has two axles, but that's what makes this model possible! The genesis of this build goes way back to the micromotor boxcab I built a few years ago. I was not too happy about various aspects of my implementation, and the model was dismantled after not too long. I had been wanting to try my hand at another micromotor locomotive since then, but I was also waiting for a good prototype to show up. So when forum member jtlan showed me the Model 40 a few months ago, I of course first thought, "hey maybe time for a new micromotor model". Alas, initial investigation indicated that the Model 40 was probably not a good candidate for micromotor traction: the locomotive turned out to be much larger than it looked - almost double the size of the old mini boxcabs. I was going to stop there, but I had a suspicion that prompted me to keep looking at different drivetrain layouts, and eventually I began to realize the size of the engine was more blessing than curse because... At 1:48 scale the Model 40 is probably the smallest locomotive by volume in which you can put a full PF drivetrain. Figuring out how to fit everything in there certainly took a couple nights, but there's basically two "tricks" I had to recognize: 1) The cab is just big enough to accommodate the battery box, but it must be in a studs-sideways orientation 2) What I call the "monkey motor" (because it came from a Creator set that made a motorized monkey) has the output shaft mounted lower than the "usual" 9v geared motor The second point is important because it allows me to connect the motor to a shaft below it with only one gear stage and without excessively large gears (a little more on this in a bit). After solving the layout problem there were of course the usual challenges of how to bolt everything together and actually model the various details of the engine. While the motor and receiver fit perfectly in the two hoods, it was difficult to tile all the sides of each end with the limited peripheral space available: the front and rear grill panels are actually attached from the bottom by hinges. The running boards are only connected near those panels and simply rest on the fuel tanks, which attach to the chassis. The battery box and the cab are connected by gravity: they simply rest on each other such that it's easy to remove the roof to access the power button and it's easy to remove the battery box to access the batteries. Two more neat details I thought were worth pointing out: 1) I used a set of click hinges to create a structurally integral step, which allowed me to mount the battery box one plate lower than otherwise: 2) There's a little bit of business done to allow 1:1 gearing with 16-tooth gears, and I'm quite happy with the torque/power curve with 1:1 gearing. The underside of the chassis: At this point some of you might be going "waitaminute...", and you might be correct! Until I tried it explicitly, I didn't think installing the 16-tooth gear at the same height as the driving wheels was supposed to work. If you do it with the old 9v wheelsets, the teeth of the gear will fall below the railhead and contact anything at that height. However, the official wheels with the rubber bands are just big enough such that the teeth now clear the railhead, even if just barely! You can see I applied permanent marker to the teeth of the lower gear for testing. None of the ink got scraped off when passing over switches, etc. Other random thoughts: The livery was not intended to be a prototypical. Since all of the 11 units built went to different industrial operators, and many seem to have changed hands some, I felt that the colors of some fictional industry was plausible. The number is kind of an easter egg, but I dunno if anyone will get it. Many of these pictures were taken in a DIY lightbox that jtlan and myself put together. This is the first time either of us have tried photographing models in such a thing, and for the amount of time we spent on our box, the results seem quite good. Other than that, I think there aren't any other construction details worth mentioning that aren't obvious in the pictures. There's a couple more pics in the gallery, but the model's so small there's not that much to see! EDIT: Instructions for this model are now for sale on Rebrickable: https://rebrickable.com/mocs/MOC-53554/NonsenseWars/148-scale-emd-model-40-power-functions-9v
