Dresine - Portuguese mow locomotive

[nalmeida]

I've been fiddling with the plans of a Portuguese mow locomotive for quite some time. Recently I got some plans for it so I decided to get started with the project. I decided to post in the Finescale Railroad Forums because I want this to be as accurate as possible and maybe I can get some help from you guys.

I'm doing this in Sketchup and then I will use the CnC to make some masters in blue foam, next I'll do some silicone molds and resin parts to work with and make the final masters. Well, that's the plan anyway.

This is the picture of the subject:



And some Sketchup preliminary work:









I still have to find the prototype to take some pictures of the details in order to continue.

[Ken Hamilton]

I really admire you guys who are so proficient with 3D drafting.....

[jacq01]

   Nelson,

   as you intend to built in H0 as accurate as possible, consider for the walls brass or thin down the material in the area around the large windows.
   Another possiblity is casting the walls including the windows with frames in a clear styrene or resin as Lima did with the german ET08 series.

   What sort of power unit you are planning ?

   I fully agree with Ken, especially with the plans for my next project taking shape.

    success and I look forward to see this evolve.

    Jacq

[nalmeida]

Thanks for the input Jacq, I know brass would be the obvious choice for this one, unfortunately I don't have the technology for this available and outsourcing would be way to expensive. So I was checking commercial plastic injected models and tried to use the same thickness they use (from 0,5mm to 1mm) At this point this is the first attempt so I might make the walls thinner. I also have an approach ready for the window glasses that I will try later on.

As for power unit I went with Bullant Power Bogie from Australian Hollywood Foundry, made the order today.

[Chuck Doan]

Interesting project Nelson. What guage was the RR this ran on?

[nalmeida]

Thanks Chuck.

It's the Iberian gauge, 1,668m (The international gauge is 1,435).

The Iberian gauge is only used in Portugal and Spain ans is slightly larger than the rest of Europe standard.

[nalmeida]

Hi there guys, well the blue foam plan went away, there's not enough quality, I might use the method for the roof since it's a complex shape. Angular shapes are difficult to do using this method. Here id one of the blue foam experiments:



So, with blue foam out of the way I tried my hand at styrene, I used 0,75 mm (030") thick plain styrene and this was how the parts came for the first version:



And the first test build:





Following Jacq's advice I made the walls thiner and at the same time got placement for the glasses which will be machined in clear styrene next week, this is version two of the walls:



According to Hollywood Foundry my motors are still 4 weeks away so I'll try to move on with the rest.

[Ken Hamilton]

Styrene seems to be working well......!
I like the rounded corners of the inner window frames.  Nice attention to detail!

[Frederic Testard]

A very precise assembly, Nelson. The dresine looks nice.

[Ray Dunakin]

Looks good so far!

[JohnP]

Very nice styrene work for the sides Nelson.

For my bridge kit master parts I have had many complex and precise parts cut with a laser. Some were cut from a sign plastic, and I have had VectorCut Dave cut eyebar parts for me out of styrene. The laser will leave a slightly textured edge that is easy to clean up if needed. You can design the parts using layers for the steps such as for your windows. The laser does a great job with arcs and circles.  Try it sometime, I enjoy having the parts delivered ready to use without fussing over mistakes.

John

[jacq01]

   A very clever solution to achieve a good thickness and seats for the windows. This is benefiting inside and outside.

   Jacq

[nalmeida]

The power train arrived from Australia, I've been making some progress with the rest of the project but haven't taken any pictures yet. I recently made a visit to a a Portuguese railway facility and took a lot of pictures and dimensions for this project so I might have some more progress real soon.

Although not my craftsmanship the power unit looks wonderful, great work from the guy at Hollywood Foundry:

[artizen]

How do you intend to hide the electrical pickups?

No rubber band drive?

[nalmeida]

Since the prototype has some tanks and hardware on each side I'm hoping the electrical pickups will be "lost" among the hardware!