The N&W SD50S: The Atlas/Bearden secret now revealed

[chessie system fan]

Mark, before you panic, remember that the SD50S shell has a thicker walkway than the regular SD50 shell. So you don't need to remove material to make it thinner above the fuel tank. You need to add material everywhere else.

That said...  the Atlas regular SD50 sill (and SD60, too) is too thick. That's probably what's confusing you.


Daniel's question is a good one.  Of the GMM fret options, does anyone know which one is closest to an EMD later GP/SD cab? Like this?
https://trainiax.net/drawings/18-emd/sd40-2/r18-emd-sd40-2-nw-ph3c2.GIF

[u18b]

We had to pause a bit on mine.
I was ready to add back the jacking pads on the rear.... only to discover that SD60 and SD50 shells have different jacking pads...
(and I had a spare SD60 walkway)   

So I went shopping and found just a walkway on ebay.

That will come in a bit.

[Mark5]

Mark, before you panic, remember that the SD50S shell has a thicker walkway than the regular SD50 shell. So you don't need to remove material to make it thinner above the fuel tank. You need to add material everywhere else.

That said...  the Atlas regular SD50 sill (and SD60, too) is too thick. That's probably what's confusing you.

All of the above.

I still need to get my train "work" area set up - I haven't found my scale rule yet (I have at least three!  ).

As for the the GMM all weather cabs, I have a few sets, but not enough to equip my fleet. I haven't gotten to the point of trying to determine which is closest to 2nd generation EMD cabs.

In terms of this thread, I am still a spectator - looking forward to learning Ron's handrail "fusion" approach. 

Mark

[u18b]

In terms of this thread, I am still a spectator - looking forward to learning Ron's handrail "fusion" approach. 

Mark

Made some good progress yesterday.  I'm developing a new method.  Hopefully I'll be able to post something in a day or two.
Since it's new, it's very tedious.  But now that I solved some problems, I should make more progress.   I didn't take many photos since I was still experimenting. 

I'm experimenting on putting spliced handrails on a U18B and completed one side last night.   
The final results will not look better than GMM stanchions and fine wire handrails (nothing looks better), but should be acceptable.

And even though it's a little challenging, it's not more challenging that all those intricate bends in fine wire, bending stanchion tops, getting the rail straight, etc.

[peteski]

I have had some success  in welding thin cross-section parts made from Delrin-like materials using heat from a soldering iron. But it is tricky and not reliably repeatable.

[u18b]

Had some success on the practice run.

On fusing handrails.
As others have surmised, this is done by melting.
And as @peteski  has observed, it's not easy.

The first time I did this years ago was in taking a stock early phase Kato NW2 and kitbashing it into a later phase that CSX owned.

The pilots of the stock model have three posts and no possible drop step.



So I bought extra handrails and isolated extra posts and created a four post pilot with drop step.
I used a soldering iron to take extra Delryn material from the sprue and paint it onto the back of the joint.






The results were excellent.




So in transitioning to the SD50S, I knew it could be done.

However, what I've learned it that for this process, the shiny slippery plastic that Kato uses is superior to the stuff Atlas uses.

[u18b]

So I decided to practice this procedure on a locomotive that has been sitting in my drawer for decades.

Our target is a U18B.




In the past, I always made fine wire handrails with GMM stanchions- which are no longer made.   So I thought I would try to install spliced Atlas U23B handrails on this model.



Now, this was a good test because what I'm about to do is a lot harder than what I need to do for the SD50S.   The great advantage is that on the SD50S I already have perfectly straight mounting holes.   That's not the case here with the U18B.


First step was to get ready.   I found some fairly side-on shots and that handrail stanchion spacing was pretty similar to the U23B rails.   My splice will be in the area of the rear jacking pad.




My first attempt to get started did not work very well.
To get the stanchion holes drilled right I thought I would scan and print the Atlas U23B rails.



I could then use a pin to mark the locations.   But it was hard to see how to line up the paper.

[u18b]

So I started over and decided to "eyeball" it.

Here are my U23B handrails.   I isolated the portion I'm working on.




The first thing I did was remove the mid-rail supports.    Keeping the rails on the sprue keeps them perfectly straight.




But I had a problem....
It was hard to get to the mounting pins.    The sprue had massive obstructions preventing me getting the rails close to the walkway.




So I got my motor-tool and shaved the back side of the whole sprue.   This was a bit time consuming but needed.




The results were successful.   Now I could lay the whole piece up close.
I started with the mounting holes near the cab.

[u18b]

To get some indicators on the shell, I used a fresh Sharpie marker and wet the back of a mounting pin.   I then quickly put the handrails in place and touched the sill leaving a mark.
I only did one or two stanchions at a time.




I then marked the holes with an awl (a pin mounted in a pin vise)




That mark with the awl kept the drill bit from wandering.   I then drilled a stanchion hole with a #78 bit.
In this shot, from left to right, you see:   Hole, awl starter, marker spot.

[u18b]

Of course, when I got to the rear jacking pad, I had to start measuring from the rear pilot forward.  So I now have all holes drilled.   

I removed the handrails from the sprue.




The rails are test mounted from the front side.    I decided to remove the stanchion directly over the jacking pad.
My splice will go in that area.




I then cut my rails and mount the front and back portions.   The fusing will be done on the sidesill with the rails mounted.




I created a tool for this process.    I split a    3/16"      1/16th K&S brass tube.   This is actually too large but it was all I had.   A tube with a smaller diameter hole would be better.   The handrails measure at about .5 mm.    The tube is soldered onto a handle.   I then cut a groove for a stanchion.




Using some spring loaded self closing tweezers to hold everything in place.....
(notice the stanchion is in the groove).






I then use the old sprue as a source for new plastic.




I melt some on the soldering iron (fresh tip, lowest setting, fine tip)...






And paint it on the back of the handrail joint.

[u18b]

Here is the fused joint from the front side.   The round tube/tool kept this side looking nice.




Here is the backside.




I then used a FRESH Xacto knife to cut the excess off and smooth everything.

This macro-photo shows one little bump on the left side that could be removed (I could see it with my eyes).




While not perfect, this definitely worked.   It passes the 3-foot rule and looks great.
Now, painting could be a different matter.   For example, it this was painted gray for Seaboard System, then the minor flaws might show up.
But in this locomotive, I'm painting it black for SCL.     The SD50S will also be black- so a good match for this process.

[Mark5]

Love it.  It used to be easy to find K&S, these days uh ... (I need to scout out hobby shops in a few hundred mile radius - maybe Hobby Lobby carries K&S)

[u18b]

Hobby Lobby and some hardware stores carry some.  Usually, not the whole line.

[NorthWestGN]

Nice techniques! And great closeup photos as well, thanks for posting this.

Brent

[peteski]

Ron, using a brass "cradle" to keep the handrails alined for the weld is brilliant.

The tubing you used might have been even better it was smaller.  Special Shapes used to sell thin-wall brass tubing that was quite small, but after K&S bought them out, then discontinued that line.   I believe Albion Alloys in US still sells that type of tubing.