Alco C425 modeling

[fishbelly]

Doing some work on an Atlas Alco C425. I am not going to go deep into detail work, but I will do some modeling work. Correcting some things and adding just a few bits of detail.

My base model is the Atlas/ Kato version. I had three chassis all ready done with sound installed and then put the brakes on. I have to do some modeling to the fuel tank and frame. Just a little to spruce it up. The first thing I came upon is the fuel tank. Judging from photos, the Atlas fuel tank is to short in length. The ends of the base fuel tank should come out to the tips of the brake clasp adjuster. This makes the Atlas fuel tank 0.200" short. That is 17.5" and is very noticeable. I have two choices. Build one from plastic or design one and have Shapeways print it. I know the surface will have print lines, but since all surfaces are flat with no detail, I can simply sand it all. The extension bulges will be made as a separate part to add on. They will have to be slightly longer too. I'll use the fuel sight glass off the Atlas tank as the sight glass detail. Since the tank will be glued to the frame, All other details will be made from styrene. Those other details are just the tank hangers.

I think this will work out well. Today I did a test with a single speaker enclosure I designed and had Shapeways print. It has internal sound chambers and they were pretty well clogged with the wax they use. I immersed it in boiling water and it worked. The walls were 0.040" thick, so no issue with them warping. Everything came out very clean. I mention this because I can do the same thing with this tank. I can boil it clean. Also, if I make the tank walls slightly oversize. Like maybe 0.005" on each side, I can then use the mill to clean up the sides and make them very smooth.

I have already cut the I-beam detail into the frame. I cut the bevel off the frame and then cut the I-beam portion. This makes it so I do not have to build all this with plastic. Prior to cutting this, I filled all the holes and gaps in the frame with styrene. As I mentioned above, I had already finished the chassis and then weathered it before I decided the bevel had to come off. It is not one of those slippery slope things. More like I could not live with the bevel and since I have the tools to easily take care of it, well it just had to go.

[nsc39d8]

Brian,

Love ALCO projects. Now for the fuel tank. You will have to pick out the exact prototype to match the fuel tank as they almost all varied.
The most reliable source I know for the fuel tank sizes was the Tiger Valley Models catalog. It has the fuel tank listing with each road name seperate.
I think when I counted them when I did my N&W C425, hence the photos I sent you from Scranton.
Anyway here is the N&W C425 from an Atlas C425 and C420 parts. Fuel tank bulges and air tanks were done by Tony Sissons from brass.

[fishbelly]

James,

Are you talking bulge sizes?

Right now I am simply working on the base rectangular tank. I have a pretty good broad side photo. Blowing it up a bit to match an architecture scale so that 1" = 1', I measure the length of the tank to be 16' - 3 1/2" front to back. That measurement seems to fall correct on the Atlas model with the trucks in the bolsters and comparing the distance from the tank ends to the brake hangers.

The Tiger Valley catalog information does not do me any good since I do not have one. I am going to go with the single bulge that I measured at 12' - 4" long.

I measured the air reservoirs to be about the same diameter as the Cannon & Co. reservoirs. The length is shorter so I will cut them down. 

[fishbelly]

A big thank you to James Wall for sending me the Tiger Valley Catalog pages.

Tells me two things. First, the tanks are 16' long. Full length bulges are from front end of tank to back end of tank and those bulges are listed as 16'. Second, my measurements off the screen were pretty darn close. Close enough for model work if I did not have the real measurements.

[edwardsutorik]

I thought I might make the fuel tank bulges out of 3/8" brass rod, cut in half lengthwise. It'll add a bit of weight. About an ounce and an eighth.


Ed

[nsc39d8]

Brian,

ALCO air tanks are a little larger than EMD tanks but the difference is not that much, maybe 1 inch.

Ed,
The fuel tanks bulges on my C425 were from brass rod cut on a lathe. It actually took four pieces, two each side, to make correctly.
The rod needs to be cut off center so you get the full diameter of the rod at 0.390 so 3/8 rod is good.

Now the bulges are not fitted flush with the bottom of the tank they are actually a couple of inches up from the bottom, 0.053 in HO.

[fishbelly]

One thing to keep in mind is each end of the bulge has a lip.

Atlas placed the bulges correctly in relation to the top and bottom of the tank.

I have decided to recreate the tank and bulges with 3D printing. The surfaces really do not have any detail on them so sanding them smooth is a non-issue. What details the tank does have can be added after the tank is assembled.

[Paul Cutler III]

One thing that might affect the fuel tank length is the "original sin" of the Atlas/Kato RS-11, namely that it only has 30' truck centers vs. the prototype's 31' centers (they did fix that with the Atlas/China version). Is that going to cause a problem?

[markfj]

Fishbelly, before you go and design all new parts, did you take a look at what Bowser has to offer?

I’ve posted these photos before when we were discussing the Atlas C424 fuel tanks a couple months ago. It may save some time using off-the-shelf parts.










Thanks, Mark J.
Reading, PA

[fishbelly]

Mark,

Never thought of the Bowser parts. Thank you. I will go ahead and design the tank, but I can use the Bowser parts to cut details off and use them. Especially the fuel sight gage. I'll pick up a pack of the air tanks too to see if I can use them.

Again, thank you Mark!

[markfj]

Here are Bowser’s part numbers for the items in the photos:

C628 air tanks p/n 107 front, 108 rear ($1.24 2016 pricing)

C628 fuel tank side p/n 87, right side ($1.24 2016 pricing)


Thanks, Mark

[lvrr325]

My C425 high hood, I was told, was made with Bowser parts and it has a nice split tank on it.

It was a Springfield show buy, $40 no box, a few years ago, which would have been a steal for an unaltered one.

I actually wondered if I could use the Bowser tank bottom and ends to save some work making the small square tank to make my Reading C424 more correct.

[12bridge]

The hobby is still sorely lacking Alco detail parts. I started buffer plates for Alcos that I hope to have done soon.

[fishbelly]

Oct 28, 2020 10:54:21 GMT -8 12bridge said:

The hobby is still sorely lacking Alco detail parts. I started buffer plates for Alcos that I hope to have done soon.

I did an Alco buffer plate a long time ago. Your post jogged my memory of it and I went looking for it in my system. I thought I had lost it. I know they work because I made them for Andy Harman and he used them on his Alco's. I saw them once at a show and they seemed to work out very well.

It was drawn from measurements taken from an Alco C425. I think I still have the paper work that was sent to me with the measurements. The portion that goes back into the pilot was built to fit an Atlas C424/425. I'll probably use it again, but change the draft gear portion.

[markfj]

Oct 28, 2020 10:54:21 GMT -8 12bridge said:

The hobby is still sorely lacking Alco detail parts. I started buffer plates for Alcos that I hope to have done soon.

Yes, and the parts that are currently available could use an update. 
This wheel slip indicator by Details West is a key Alco truck detail, but it is undersized when mounted on Bowser sideframes and the casting is showing its age.


Fishbelly: Are you going to make that buffer plate available at Shapeways or somewhere?

Thanks, Mark

[fishbelly]

I can make the Atlas one available. You have to cut the pilot open to use it, so you loose the ability to have the draft gear box hold the sill to the frame.

I also made the wheel slip cone and the speed recorder cone. It is just the cone without the bolt detail and you have to use the Detail Associate wheel slip unit. The speed recorder has a little different looking cap and I use a Details West speed recorder module for it.

These side frames are for an Atlas U33B project I have shelved for the time being. The truck on the right has the two wheel slip cones. The truck on the left has the speed recorder mount and you will notice it is not really a cone and has three gussets supporting the boss.



Here is what the assembly of the cones looks like. These are designed to fit the Kato AAR truck and I believe they will also fit the Atlas/Kato AAR truck. There is a pin on the back of each part. The four cylinders are tools that fit over the molded on journal cap and allow me to center drill the journal. After I center drill the journal, I put the side frame in my mill and using a 0.040" milling bit I carefully cut the journal cap off flush to the bolted surface.

[fishbelly]

While doing some truck retainer detail parts, I came to notice that the Atlas frame sits 0.060" to high off the rails. Judging from photos, the bottom of the tank is pretty much even with the bottom of the brake slack adjusters. This means the Atlas tank has to drop 0.060". When I do this and drop the bottom of the frame, it puts the distance from the top of the truck side frame to the bottom of the frame at roughly the correct distance.

So it look like I have to build out the bottom of the frame by 0.06". Interesting stuff and could make this model look even better than it is. It will definitely give that really tall frame look. To me something just was not right with the distance from the truck to the frame and now I know why.

Cool!

[fishbelly]

Getting back to this project. I did a little more research on the fuel tank bulges.

I am designing the full length fuel tank. Duplicating the ones that the PRR had. Found out some changes I need to make to my design. On the engineers side, the bulge is 14' long which leaves a notch at the front to mount the air filter. On the brakeman side the bulge is full length at 16'. I will make the change this weekend and order a new one. The one I currently have has both bulges at 16'. Looks cool though.

[fishbelly]

I understand that the Alco air reservoirs are a bit larger in diameter than the EMD air reservoir. I do have some photos of them, but none that I can scale off of. The EMD air reservoir is 16" in diameter. Looking at the Alco photos and comparing them to the Atlas model. I come up with 18" diameter. I cannot really imagine that these would be made in oddball dimensions and locomotive building is not precision rocket science. Especially back in the late 1960's. More like glorified tractors. I also theorize that they would use standard pipe or tube size and built the parts. After over ten years of visiting museums and getting up close to take measurement and photos. I have come to see that the structural components are no more than standard structural steel sizes.

Unless someone can prove me wrong and or give me the actual Alco air reservoir dimension, I am going with 18". I can use the Atlas representation to get the length as well as some profile photos I have of a C420. Then I can design it to be 3D printed. I think they will come out OK. I'll design photo etch for the straps or possibly instead just use 0.005" styrene and cut straps from it. That works too.

[fishbelly]

This is an Alco fuel tank I designed to fit the Atlas C424/ C425 model. From my research and logical measuring and scaling off photos. The Alco C424/ C425 fuel tank is 16' long front to back.

For my modeling, I chose the full length extra capacity side bulges. Similar to the PRR units, but not the same as I am not modeling a PRR C425. My design can use any configuration of the additional fuel bulges. I just need to change the lengths. You will notice one of the bulges is shorter. That is because on the right side of the tank (engineers side) the air filter is mounted on the tank. I want to model that. That makes the right side bulge 14' long as it is on the PRR units. If I wanted this to be a PRR fuel tank version. I would only need to split the long bulge into two parts.

I also designed the air reservoirs since nobody makes Alco air reservoirs. These are designed at 18" diameter. I made the air reservoirs the same length as the ones molded onto the Atlas tank.

The half circle part in the body of the fuel tank is a drill guide for the fuel filler and fuel pressure gage. It was hard to tell what angle the fuel filer is at so I put two guide holes. One at 25 degrees and one at 30 degrees. Looking at photos, that is what it looked to be. The little "V" shaped notched in it are so I can line up the holes with a line I put on the tank to locate where the holes need to be drilled along the tank.

I already have a test sample of an earlier design that is like this one and it cleaned up REAL nicely and glued together beautifully. This is just the base model of the tank and other detail parts will be added and designed to go with it. I think this tank will greatly increase the coolness of the model.

[canrailfan]

This is another top-notch thread about building models. This type of thread is why I joined the ARF (and the original AF before that). Thanks to fishbelly et al.

[fishbelly]

Thank you canrailfan. 

Today I finished the design for my early tall air filter. I had measurements from all my journeys to museums and short line railroads for the early short and for the early medium air filter. The tall filter is a combination of the two. I think these parts will clean up real good. I found that I can sand them smooth with the grit blaster if I shoot them between 60 to 80 psi. The bracket will fit in the location on the front of the fuel tank bulge as seen on some late PRR C425's. 

The brackets do look thick, but that is because everything else is so small. The thickness is the minimum for Fine Detail Plastic at 0.012". I could not make the drain valve that comes off the bottom of the air filter. It would have been way to fragile. I'll cut the part off the Details West filter and install it on mine.

Now it is time to just wait for the parts to come in. The fuel tank and these parts.

[ambluco]

You going to make available on Shapeways?

[fishbelly]

Feb 28, 2021 11:27:12 GMT -8 ambluco said:

You going to make available on Shapeways?

I will once I make sure the parts work out properly.

[markfj]

Please add the Alco buffers to Shapeways too (if they aren’t already)! Really looking forward to seeing this one completed.

Thanks, Mark

PS: You can “kind of” see how the buffer fits to the frame in this shot. And the filter mounted to the fuel tank is clear. What a sad looking pup, but would make a really neat modeling project.

[fishbelly]

Mark, Thanks for posting this photo. James Wall sent me some good photos of this area and it gives me a real good view of the draft gear box. I also have drawings with prototype measurements of the buffer plate that a fellow modeler sent me a long time ago

Yes, I will be redesigning my draft gear/buffer plate to look like the prototype. After I gat the fuel tank and frame bits sorted out, I will move to the draft gear and buffer plate. A slow process, but eventually it will get done.

It would be nice if I could find a museum or something that had one of these units on the east coast somewhere that I could go to and get information off of. Anyone know of a place?

[lars]

The Reading Company Technical and Historical Society has a C424 and a C630 www.readingrailroad.org/roster/roster_thumbs.shtml#diesel_locomotives  The U30C is gravy, too.

[fishbelly]

Lars, is this a museum? Do they let you have access to the locomotives? Not necessarily to climb all over them, but rather to photograph and maybe take measurements from.

[lars]

Someone else can confirm but I think the are accessible. The physical address they list for the museum is where the locomotives are located and the site shows there are yard tours www.readingrailroad.org/visit.shtml

[12bridge]

I have full access to a C420 if anyone needs anything.