Articles - Scratchbuilding: A Steam Locomotive

The Premise

This is going to be an article that will, literally, be years in the making. For my chosen railroad and era, I need steam locomotives. However, there aren't that many available in S-scale, especially not in the wheel configurations that were documented on the PRR branch line that I model. So, this article will be a tale of how I am going about building one of these.
The only minor issue is that, I have never built one, nor am I a machinist! However, I thought that this might be a perfect opportunity to document one's journey into scratchbuilding a steam locomotive, from a novice's perspective. This is something that those who want to tackle such a feat are in need of, yet that resource is not available. I have found no book or web site that describes the process.
My "givens" at this point are as follows:
a) I have built 7 freight cars so far from scratch, using mostly styrene plastic;
b) I am a fairly capable woodworker, with the requisite tools on hand;
c) I really love to build things from scratch;
d) I am excited about this project.
There are at this moment two people that I know of that build their own steam locomotives in S-scale, so I can ask them for tips or advise.

The Research

Researching building a steam locomotive from scratch requires two paths. One path is to decide upon which steam locomotive or locomotives to build and to learn about steam locomotives in general. The other path is to find out what is available on the modeling market, what to buy, what to build, and what tools you are going to need.
For the branch line that I model, the following steam locomotive wheel configurations were observed: 4-6-0, 2-8-0, 2-10-0. The first was used primarily for passenger trains, and the latter two primarily for coal and general freight transport. I plan to build at least one of each of these, so I am looking at them all for any things that they have in common. For example, the 2-8-0 and the 2-10-0 had the same 62" drivers. All had 33" pilot wheels. So, if that is my plan, then when I find a source for these wheels, I know how many I need to order.

The Experimentation

When you start a new project, there are a certain number of items of higher risk than others. Some things you may already know how to do, so those can be ignored early on. Other things that you do not know how to do, are the tasks that need to be examined to see if you are capable of doing them, because otherwise the project may fail.
These are some of the higher-risk tasks I can see for myself (in no particular order):
- how to create a round boiler body.
- how to create or acquire the various wheels.
- how to connect a motor to the necessary gearing to get the engine to run at the speeds desired.
- how to build the exterior drive mechanism (the rods).
- what material should the engine be built out of?
- both sound and battery-power component need to be installed.
- having reasonably accurate plans or measurements.
Some of the lower-risk items are as follows:
- building the tenders.
- acquiring the correct trucks for the tenders.
- building a collection of photos to use as reference.

The Acquisition

In this section I plan on documenting the materials, parts, and tools I had to buy to build one or more steam locomotives. Also, if I used something that I already had, I will list it in this section as well, so that you can see what all is required.
One tip I received with regard to the driver wheels was to see if one of the brass manufacturers is going to use that same sized wheel in an upcoming project, so that they might be able to order a set of extra ones for you.
Another tip I have received is to convert the desired wheel sizes into actual dimensions and then convert those into the scale dimensions of other model railroading scales, to see if they might be available. For example, in S-scale we can look into HO-scale wheels. The tire widths and flanges might be smaller, but that just makes the S-scale model more "scale"-like.

The Construction

The actual building of the steam locomotives will be covered in a separate set of articles in the Equipment section of my web site. This article is mostly about the period leading up to the formal construction phase.