STEAM GIANT SWAN SONG

As half of a century rolls by, the reign of steam power on railroads marches towards its end. Diesel and electric locomotive have become more efficient and popular, with both modes of traction rising rapidly to take the lead from steam. And yet, it is now that steam power reaches its peak in railroad engineering. Giant articulated steam locomotives with two sets of driving wheels, four cylinders, and enormous high-pressure boilers continue to roam the rails. Their great strength and immense amount of power allows them to pull the heaviest trains with ease, keeping pace with newer modes of power for a little longer.

Somewhere in the Blocky Mountains, snorting furiously up the steep grades with one of the longest and heaviest freight trains in tow, is a true giant of steel and steam. It is the Iron Sirius, one of the largest and last steam locomotives ever built. Its class is the pride of the line, the king of the fleet, the only locomotives that could conquer mountains alone. Even as the railroad buys more advanced diesels, this monster steam locomotive will continue to be hard at work for a little while longer, keeping pace with the newcomers with ease.

The Iron Sirius was loved by the people of its railroad. It escaped the fate of scrap that befell so many others, and was put aside for preservation. The railroad set it up just outside of their headquarters, and there it stood for many years. Visitors would come by to wonder at this titanic machine, climbing inside the cab to imagine how it must've been like to drive it. Now, there are now talks about restoring this locomotive to working order. While this may require significant changes to its appearance to meed modern safety standards, it will be worthwhile to bring an enormous piece of history to life once again.

DESIGN PROCESS

INSPIRATION

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 had the opportunity to see one of these giant locomotives up close a long time ago, which is the main reason why I was inspired by this particular class. I chose to make it in 1:48 scale because this is a common modelling scale for model trains, 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.

CHALLENGES

A major challenge in building a locomotive like this is the articulation, or the ability to flex around curved track. This required a lot of trial-and-error in Studio, using the hinge and collision tools to line up the wheels with curved track while making sure other parts of the build did not clip into each other. I also took reference from other physical models to make sure the distance between the flanged drivers was the right size to avoid getting the flanges stuck on curves. Some details on the undercarriage had to be sacrificed to achieve the appropriate range of motion and stability for standard R40 curves, but there's still plenty to look complete. The engine units use big turntable parts, allowing for both articulation and torque transmission from the motors to the wheels. The pilot and trailing trucks use rotating pins and linkages. The tender uses rotating pins and laterally sliding axles.

Both engine and tender are composed of large "SNOT Cores," a technique I've used on several locomotives and trains. The cores are hollow structures composed of modified bricks and brackets (Studs Not On Top or SNOT parts), plus a few normal upward studs jutting out, as well as bar-holding clips or holes. Exterior details are built as large, flat sections that effectively wrap around the cores. The idea is simple, but the real trick is building a core that has all the necessary 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 boiler barrel tapering with a narrower front end and wider rear end, 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 and 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 name Iron Sirius is based on the naming conventions used in older train sets, consisting of a gem, mineral, or metal to describe the color of the locomotive and an object related to the sky. Sirius originates from 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.

SPECIAL FEATURES

The tender has easily removable top panels, revealing a large hollow cavity inside containing several alternate parts. These include a pair of smoke deflectors, an alternate dynamo, alternate firebox sides, simpler tender lettering tiles, and the top of an oil tank to replace the coal load. The alternate parts can be used to customize the appearance of the locomotive, reflecting several design changes made to the real-life inspiration over the years. A flat-ended wrench tool on the rear of the tender can be used to help pry off tiles for customization.

The locomotive can be motorized in two different ways. Personally, I prefer to power the engine directly through the drive wheels on the engine. However, there is also the option to put standard train motors or 9V motors in the tender for those who prefer that method.

BUILD STATS:

Parts:
- Engine = 1800
- Tender = 810
- Alternate Parts = 110 parts
Lengths:
- Engine = 73.9 studs
- Tender = 37.3 studs
- Engine + Tender = 111.6 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/oil load
- Alternate parts and tool for locomotive customization stored inside tender
- 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
  - Option 2 requires removal of alternate parts from tender