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July 10, 2007  

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A free lance 2-4-0 for the beginner




Written by Bill Oberpriller

When I first saw a picture of the Wato Narrow Gauge 2-4-2 in a magazine several years ago I decided this was the locomotive for me.  At the time the castings were available from Australia.  The cost of shipping was prohibitive so it went to the back burner.  When Roll Models started selling the plans and castings I ordered the plans.  After looking over the plans I decided to design my own 2-4-0 based on the castings.  The major changes I made was to make a simple bar stock frame, a fire tube boiler, and Stephenson valve gear.  This made the construction much easier and cheaper than if I would have built the locomotive per the plans.

For the beginner or new comer to the live steam hobby there is no such thing as a simple easy to build steam locomotive.  Even in it's simplest form a steam locomotive is a complex piece of machinery.  There are several appliances that need to attached to the locomotive for it to work properly.  It needs a heat source hot enough to provide enough steam so the locomotive can operate continuously.  It needs a water delivery system to replenish the water used in providing steam to the engine.  It needs a lubrication device to supply oil to the cylinders.  So it not just a matter of building a locomotive.  Many builder start a locomotive project and get to the point where they have the chassis running on air.  They soon realize that building the chassis to that point was the easy part.  Many beginners take on a project much more ambitious than their resources can handle.  The biggest obstacle is not enough money.  The second is a lack of skills. The third  is not willing to spend the time  necessary to complete the project.  My first locomotive project was a failure because I didn't have the machinery or the money to complete the project.  For the second locomotive  I took a simpler design idea from a book and free lanced a locomotive with some of the parts from the first. 

If you are a new comer/beginner to the live steam hobby, there are several skills that you will need to develop in order for you experience to be successful.  You will need to be able to operate a lathe, a milling machine, and you will need to learn to tig weld.  Most beginners understand the machine work and have no fear of jumping in head first with the purchase of a lathe and a milling machine.  However, when it comes to the welding part, they all start running for the hills.   I purchased a "Miller Econo Tig" fifteen years ago.  Many of the parts on the above pictured locomotive are weldments.  It would be impossible to be successful in building a locomotive similar to the one above without being able to weld.  Without being able to weld, your chances of success in building a steam locomotive are very low.

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click to enlarge

So what you will need in the shop before you start building is a lathe, a milling machine, and a tig welder.  A belt sander comes in real handy, bandsaw, grinder, both stationary and portable.  The list goes on and on.  My theory is that you can't have too many tools.

A couple of things that will also affect your success is the number and complexity of the parts required for your project.  If  the locomotive you decide to build has numerous complex parts to make such as a Northern 4-8-4 as compared to a Narrow Gauge 2-4-0 will determine your chances for success.  For a first project, keep it as simple as possible.  A little locomotive with 4 wheels on the track is a lot more fun than a 1/4 finished one with 16 wheels on the bench!

Know your limitations

Although I designed this locomotive to be as easy as possible to build, there are still minimum requirements that need to be considered. You can get by with a 12” lathe and a bench mill, but a 14” lathe and a Bridgeport size mill is better. You can’t build this locomotive with a 9” lathe and a milling attachment as I read in a catalog years ago. Only consider buying a set of castings when you have the capabilities to machine them into useful parts. When I first started out many years ago, I bought the first two or three sections of a locomotive kit only to find out that I could not machine all of the parts on my Craftsman lathe with a milling attachment. You could say that the money spent was worth the lesson in learning my limitations. If this is your first attempt at locomotive building, you may want to consider getting the big parts machined by an experienced builder. Cast iron cylinders can even humble an experienced machinist not familiar with the characteristics of cast iron castings.

This locomotive was designed with a minimum number of parts. The parts that are required are designed to be as easy to make as possible. For example, there are no parts that need threads cut on the lathe. There is no steam driven water pump, no injector, no axle pump to make and no blower in the smoke box. The boiler is a fire tube boiler with a burner in each flue, so there is no fire box. Where the fire box would be is mounted a pressure washer pump driven by a chain with a sprocket on the rear axle. In the tender is a 12 volt ShurFlo 150 psi pump that will supply all the water you can use for two days on one charge of a garden tractor battery.


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The only castings used on the chassis are the ones pictured above. The castings were purchased from Roll Models.

Valve Gear Assembly

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The valve gear is shown assembled on the aft axle for the left cylinder.

The eccentrics can be made from either steel or cast iron. I prefer cast iron so I bought a length of 4” cast iron bar from McMaster. Expensive, but worth it in the long run. The straps were made from cored bronze stock. The tabs and strap are steel welded to the bronze bearing stock. (You need that TIG welder.) The link is made from ¼ X 1” and ¾” bar stock. I made the link straight for simplicity. The block is made from 1” square bar stock.
The Frame

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click to enlarge

The frame for the most part is fabricated using 1” square bars stock. The top rails should be bolted together and the slots machined in both pieces at the same time. This will insure that both side are identical. I purchased a 4 jaw scroll chuck to face off, drill, and tap the ends of the frame members. The 4 jaw scroll chuck also came in handy for machining the bearing cavities in the journal boxes.

“Building” the locomotive as a 3d model has several advantages. The builder will be able to see what the locomotive will look like before making any parts. If the builder sees something he doesn’t like, he can change it without having to spend time and resources making new or reworking existing parts that he already spent on. Another feature is that conflicts and collisions of parts can be eliminated.

Written by Bill Oberpriller

Visit Bill's Narrow Gauge 2-4-0 page

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