So there are lots of things I like in the realm of trains, but if I was to narrow things down regarding what to actually model, I’d lean toward the era starting with 2nd generation EMD products. Of the three common EMD 2nd gen switchers - sw1500, mp15dc, and mp15ac, I’m most interested in the sw1500. I’d rank the mp15ac second, and the mp15dc third. Atlas produces the mp15dc, presumably because they wanted to share product development across three scales, and they didn’t want to go up against the Athearn sw1500 in HO. So I would need to either scratchbuild or kitbash to get a high quality model of the sw1500.
Once I learned more about the prototype loco, and what was available as a starting point in O scale, I discovered I could kitbash an effective model by blending superstructure parts from the Atlas mp15dc with drive parts from the Atlas sw8/9/1200 (referred to as sw9 going forward for simplicitiy) series switcher. At its simplest, the kitbash could be achieved in three steps: shorten the frame, modify the hood, and swap drive trains with the sw9. I came to realize, right about the time I started cutting things apart, that there were additional issues that I didn’t foresee, but even then the simple kitbash would be straightforward.
At the other end of the spectrum, there are a lot of opportunities with the base model to improve detailing and accuracy. Of course, detailing can lead to a slippery slope, one which I currently sit comfortably at the bottom of. By the time I started this project, I’d decided to adopt p48 standards for track and wheels. I also didn’t foresee having a layout anytime in the immediate future. So I decided I would be a model builder instead, so I could stop sitting around planning things and start actually modeling something. Adding to these two conditions, I’m also very picky about accuracy and detail - yeah I’m one of those guys . As a model builder, with a finite project scope, and a disorder, it made sense to push the detail on this project to the furthest extent possible. I’m fortunate to have some capability with 3d modeling - actually it’s my best modeling skill at the moment - so I could create components from scratch as well as modify or utilize parts already available on the market.
Obviously, another modeler attempting a similar kitbash, or an sw1000, could pick any point on the spectrum to aim for. For the purposes of the initial project description, I will ignore all the extra work, and focus only on the bare minimum changes required for an sw1500. Once I have the basics outlined, I’ll describe how to go off the deep end.
WHY THIS PROJECT WILL WORK
Everything necessary to complete the kitbash has already been produced by Atlas, either as part of the mp15dc line, or as part of the sw9 line.
The mp15dc is essentially a stretched sw1500. It has a longer frame, different trucks, and a longer hood. But many of the styling cues and details are the same for both models, so all hood, cab, and frame parts from the mp15dc can be modified with minimum effort for the sw1500.
In a happy coincidence, the sw9 and sw1500 prototypes share the same bolster center dimensions and the same truck wheelbase, plus Atlas makes both AAR Type A and Flexicoil switcher truck sideframes used on the sw1500. In another coincidence, the Atlas sw9 and mp15dc share the same motor, motor mount, gearbox design, and gearbox mounting. The only distinctions between the two drives are truck wheelbase (AAR Type A/Flexicoil = 8’-0", Blomberg = 9’-0") and universal drive shaft components. Therefor the trucks and motor from an Atlas sw9 are a drop-in replacement in a modified mp15dc frame.
BEGINNING PARTS LIST
(1) Atlas mp15dc model - this can be either powered or unpowered, 2-rail or 3-rail, and really the drive components aren’t needed at all. From the frame up, including the fuel tank, will suffice. One thing to consider is that a 3-rail frame will have a larger coupler opening in the pilot. I don’t consider this to be an issue because it can filled in fairly easily (and will have to be filled in any case if a scale pocket is used). NOTE: there are three versions of the mp15dc model, each having a different condition for the hood directly in front of the cab. Two versions have boxy housings (square and tapered in Atlas parlance) sticking up from the hood for paper air filters. There is a third version without filter box (labeled “standard”) with a traditional sloped hood course. The standard version most closely resembles the sw1500 hood, but in reality the sloped section on the mp15dc is longer than the corresponding section on the sw1500, and will need to be replaced. Any of the three hoods will work, but the standard is probably still the best bet because the area forward of the sloped section most closely matches the desired profile. At a minimum, BNSF, BN, Frisco, Alaska models all have the standard hood. There may be others. The undecorated version currently offered for preorder from Atlas is also the standard hood version. However, nobody knows when these models will be produced, if ever, so it would be best to look for a donor through other sources.
(1) Atlas sw9 model - actually the only parts needed from this model are the trucks, motor assembly, and any associated mounting hardware. Again, this can be 2-rail or 3-rail, the same parts are used in either version. NOTE: the motor assembly from the mp15dc cannot be used with the trucks from the sw9, even though it appears the same . The diameters of the attached telescoping drive shafts are not the same.
I’ll take a break for a while, then start back in describing the frame modifications. Stay tuned.