THE SWAN SONG OF STEAM

Halfway through the 20th century, the reign of steam traction on railroads is coming to an end. It was contested, then usurped by newer forms of motive power, such as diesel engines and electrified lines. But even in this twilight, steam engineering has reached a peak with articulated locomotives. With two full sets of driving wheels, four cylinders, and an enormous high-pressure boiler generating an immense amount of power, locomotives of this caliber were able to move just about any load with ease.

Somewhere among the Blocky Mountains, charging up the steep tracks while filling the air with a thunderous crescendo from its chimney and whistle, is a true giant of steel and steam. It is the Iron Sirius, one of the largest and last steam locomotives ever built. It's pride of the line, the king of the fleet, the only class that could conquer mountain grades alone. Multiple smaller locomotives would be needed in its absence, and few trains were as long and heavy as those pulled by the likes of the Sirius.

Even after it pulled its last train and was replaced by diesel-electric locomotives, the Iron Sirius was held in high regard by crews, rail fans, and even the railroad management. Instead of being scrapped after retirement, the railroad put the locomotive on display near their headquarters, and there it stand today. Though it is very unlikely that such a machine will operate ever again, the Iron Sirius stands as a monument for the end of steam and a magnum opus of its railroad's motive power, ensuring it and the era it came from will never be forgotten.

And who knows? Maybe someday, someone will fire up that sleeping giant to roam the rails again.

DESIGN PROCESS

This locomotive is a 1:48 scale model of a American articulated locomotive built in the 1940s, one of the largest in the world. I actually had the opportunity to see one of these giant locomotives up close, which is the main reason why I wanted to model this particular class. I chose to make it in 1:48 scale because this is a common modelling scale for train MOCs, and it doesn't look too oversized compared to the official driving wheel parts. I also enjoy the challenge of creating such a large model that not only looks accurate to the prototype, but can also function and run on regular track.

A major challenge in building a locomotive like this is the articulation, or the ability for the locomotive to flex around curves. This required a lot of trial-and-error in Studio, using the hinge and collision tools line up the wheels with curved track while making sure other parts of the build did not clip into each other. Some details on the undercarriage had to be sacrificed to achieve the appropriate range of motion and stability for standard R40 curves. The engine uses large turntable parts, allowing for both articulation and gear transmission from the motors to the wheels, as well as a few linkages for the pilot and trailing wheels. The tender uses rotating pins and laterally sliding axles.

Both engine and tender are essentially composed of large core structures with the outer walls covered in sideways studs from bricks and brackets, plus a few normal upward studs jutting out and some bar-holding clips or holes. I then build all the exterior details on large sections, and attach those bigger sections to the core. The idea is actually quite simple, the real trick is building a core that has all the right attachment points while being rock-solid. Mixing bricks and brackets allows not only allows for enhanced stability, but can also help with finer details such as the smokebox being narrower than the boiler, the boiler itself being slightly tapered so that the rear is a bit wider than the front, and the inset ladder at the rear of the tender. One section I am particularly proud of is the rear course of the boiler, where a pair of long, flat assemblies are held at a non-system width by bars and clips to match the width of the sideways slopes to fill out the boiler curve.

While many builders may give their models a completely stud-free finish with smooth tiles, slopes, and panels, I find that studs can be useful as detail on their own. They can give the impression of rivets, fasteners, small access panels, or just a rough surface like the sides of a firebox or a pile of coal. Sometimes individual, isolated studs can represent lights or buttons. It all depends on where the studs are and how they are arranged.

The locomotive can be motorized in three different ways. Personally, I prefer to power the engine with a motor transmission turning the drive wheels on the engine. However, there is also the option to put standard train motors in the tender for those who prefer that method. This method is also recommended for electric metal rail users.

The name Iron Sirius is based on the naming conventions used in some previous train sets, consisting of a gem, mineral, or metal to describe the color of the locomotive and an object related to the sky. Sirius is the name of the brightest star visible from Earth in the night sky, which is part of the constellation Canis Major, or the Great Dog. This is also the reason why a dog accompanies the engineer and fireman in the cab. The big brick-built logo on the tender is loosely based on the logo found in a lot of other train sets, consisting of a circular target with two arrows pointing outwards at the sides.

BUILD STATS:

Parts:
- Engine = 1856
- Tender = 849
- Display Base = 166
Lengths:
- Engine = 73.9 studs
- Tender = 37.3 studs
- Engine + Tender = 111.6 studs
- Display Base = 134 studs
Widths: Mostly 9 studs, 12.8 studs at the motion
Heights: 14.2 studs from rail to chimney, 14.6 studs from rail to coal, 15.1 studs overall
Functions and Features:
- 1:48 scale
- Working driving wheels and motion
- Runs on R40 curves
- Fully decorated interior for engine cab
- Working hatches on cab roof and tender sides
- Removable coal load
- Powered-Up Requirements
  - Option 1: Engine + 1 Hub + 2 Large Motors
  - Option 2: Tender + 1 Hub + 2 Train Motors
  - Cab roof hatch and removable coal load allow for access to battery