Building Archbar Trucks for Flatcar #5121
Building a railroad is a lot of work! Even things that seems like a relatively small, simple project can take a lot of time to finish. Just for fun, I decided to document everything it takes to build a pair of a "Cheap and Dirty" archbar trucks for flatcar #5121. The original trucks used for #5121 were built when I was in High School as a shop project. I finally finished them and put them to use under the flatcar back in 2000. Even though they served well for the past eleven years, they had some problems so I decided to build a new set of trucks for the flatcar so I could rebuild the old trucks for use under a new caboose! Lots of pictures on this page, scroll down with me to see what it takes to do this "simple" project! Step 1: We have to begin somewhere... in this case it starts on the internet. New bearings and springs are bought on Ebay for a cheap price. Bearings are 6205 ball bearings with seals, springs are small block Chevy valve springs. Also, 12" of DOM 2" ID - 2.5" OD steel tube is at the top of the picture, courtesy of Speedy Metals. ----- Step 2: First, the DOM (drawn over mandrel) steel tube is cut into 1-1/8" long rings. ----- Step 3: Next, the rings are faced on the lathe so they are 1" long, then bored 0.75" deep to 2.050" diameter. This will allow the bearings to have a slip fit into the rings. This picture shows a ring being bored on the lathe. ----- Step 4: All eight rings machined! The one on the lower right has a bearing in it. Next, I will need to cut out and bend the steel for the frames. The rings will be welded to the steel. ----- Step 5:
OK, there is a lot going on in this step. All the individual parts of the sideframes have been cut out of 1/4" x 1"
hot rolled steel strap. The bottom sideframe is clamped together and ready to weld.
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Step 6:
This is the finished archbar truck sideframe after welding. I have cut out and welded on rectangular covers
over the bearings. Not pretty, but good enough for a utility truck under a working car!
Keep in mind that we have to weld up 4 sideframes for the 2 trucks, so there is a lot of repetitive work.
Next up: axles & wheelsets!
----- Step 7: Four axles have been rough cut to length from 1.250" diameter cold rolled steel. Wheels are hand-me-downs from the WF&P RR - Originally cast in 1945! ----- Step 8: The axle is chucked up in the lathe with a steadyrest to hold the far end in place so it can be centerdrilled. ----- Step 9: With the end centerdrilled, the tailstock is moved back so the end can be faced square. ----- Step 10: This is the faced end of the axle. Because of the setup, I do steps 8, 9 & 10 on all four axles before going on to Step 11. ----- Step 11: Each axle is chucked up in the lathe again, with the faced end even with face of the chuck. By lining this up, I can set the carriage in one position for facing the other end of all four axles. This will make sure they are all the same length. Once again, because of the setup, I perform steps 11 - 14 on all four axles before continuing. ----- Step 12: The other end of the axle is center drilled, just like the first end of the axle. ----- Step 13: After center drilling, this end of the axle is faced, which determines the length of the axle. ----- Step 14: Both ends of the axle are now faced square, center drilled and the axle is the right length. After all four axles are center drilled & faced, the steady rest can be removed from the lathe. ----- Step 15: The axle is now chucked up with the far end held in place by a live center in the center hole we drilled before. A line is scored directly in the center of the axle. These axles are 17.25" long, so the line is 8.625" from either end. ----- Step 16: A second line is scored 5.625" from the centerline at the tailstock end. The center of the axle isn't machined, just the part from this line to the end of the axle. ----- Step 17: The axle is machined back to the second scored line. In this case, it will be turned to a diameter of 1.128" - just ignore the measurement in the next picture! ----- Step 18: After machining the diameter for the press fit of the wheel, a mark will be scored 0.625" from the end so I can machine the journal for the ball bearing. ----- Step 19: Here the journal for the ball bearing has been machined to size. A line will now be scored 1.625" from the large, unmachined diameter of the axle. ----- Step 20: A paltry 0.010" is trimmed up to the line I just scored. This makes it easier to press the wheel into place, since it doesn't cover this part of the axle. ----- Step 21: The axle is swapped end for end in the lathe, and steps 16 through 20 are repeated for the other end. ----- Step 22: The finished axle is removed from the lathe. Step back and admire your work! Now we just need to perform steps 15 through 22 on both ends of the other three axles. But before I do that, we will press the wheels on the finished axle with the 20 ton press! ----- Step 23:
The wheel is set flange side up on the press plates with the axle in place. A piece of aluminum protects the other end of the axle from the press. ----- Step 24: The axle has been pressed into the first wheel. ----- Step 25: The other wheel is placed flange up on the press plates and the axle is swapped end for end. The axle is pressed in the second wheel just like the first wheel. ----- Step 26: The wheelset is removed from the press. ----- Step 27: The bearings are tapped into place. The bearings have very light press fit on the axle. ----- Step 28: With another wheelset done, it's starting to look like an archbar truck! OK, this isn't really a step. I just wanted to see what the wheelsets looked like with the sideframes. I still have two axles to machine and press on the wheels, but after that I will start building the bolsters and springplanks.
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Step 29:
The Final Axle! Boy am I glad to get it done. Wheels were pressed on right after I took this picture.
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Step 30:
Now that all the wheelsets are assembled, the spring planks were cut out of steel and drilled to bolt
to the sideframes.
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Step 31:
With the spring planks bolted in place, the bolsters are cut from 3" channel.
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Step 32:
Step 32 is a lot of little steps. Many different parts are cut, drilled and tapped so the trucks can be built.
The parts above will be welded in the ends of the bolsters, so endplates can be bolted on.
I try to arrange work so the bandsaw is cutting some parts while I am drilling, tapping and deburring others.
Remember, I have to make at least 2, 4 or sometimes 8 of each type of part.
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Step 33:
These are the various parts that were cut, drilled and tapped in Step 32!
Look carefully in the following steps and you will see where each part is used.
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Step 34:
A large hole is torched in the bolsters for access to the kingpins.
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Step 35:
The welding begins! These little blocks ride on the inside of the sideframes.
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Step 36:
The center plates for the kingpins are welded in place.
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Step 37:
The parts I tapped earlier are welded in the ends of the bolsters.
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Step 38:
The (almost) finished bolsters!
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Step 39:
The Trucks are assembled. They are still incomplete; I will weld on the plates on either side of the
kingpin plate after I inspect the flatcar. They keep the car from rocking too much.
In case you are wondering why I didn't just turn the bolster over so the flat side was up, it is really about the same
amount of work either way. If I would have put the flat side up, I would have to weld in plates so there would be a
flat place for the bolster to rest on the springs. I have done bolsters both ways... feel free to use whichever
method you want when you build your trucks!
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Step 40:
This is our victim: Flatcar #5121, built Eleven years ago. I made the original trucks as a High School
project when I was a teenager. They have friction bearings and aluminum wheels, not to mention
a bad habit of spitting out the springs at inconvenient times! They will be rebuilt with old WF&P
cast iron wheels, new bolsters and new springs for use under a caboose.
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Step 41:
First things first, unload the flatcar. This is a length of SA-106 pipe for future boiler construction.
It weighs more than I do, so it is carefully rolled off the flatcar.
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Step 42:
A couple of the deck boards are removed from both ends of the car.
At this point, I measure the car height so I can make the proper thickness spacers for the new trucks,
and I also look to see where the side plates need to be welded to the bolsters.
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Step 43:
The flatcar is rolled off the old trucks!
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Step 44:
How do I transport trucks from the shop to the railroad and back? A 12" gauge moving dolly!
The old trucks are ready to take to the shop, while the supervisor carefully observes my work.
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Step 45:
The old and the new, albeit with really old wheels!
As you can see, the old trucks have a cast aluminum Bettendorf style sideframe.
I made the pattern, rammed the molds and poured the aluminum when I was a teenager.
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Step 46:
With the information gathered from the flatcar, the plates on either side of the kingpin are welded to the
bolster. A spacer plate for the kingpin has also been cut, drilled and welded to the bolster.
Why am I welding it on? Well, I may or may not have drilled too big of a hole in the original plate...
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Step 47:
The new trucks are finally complete! Obviously, the supervisor approves.
I'm not even going to bother spraying any paint on the trucks, they will get a nice layer of rust pretty soon!
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Step 48:
The new trucks are set in place, and the body will be rolled on top of them.
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Step 49:
The trucks in place. It got dark, so I didn't get the flatcar quite finished.
As you can see, the deck boards are just resting in place. This car uses wood blocks on either side of the
kingpin that bear against those plates we welded on in Step 46 to keep the car from tipping.
I need to cut new blocks to the proper height and assemble them along with the deck.
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Step 50:
It is hard to see in this picture, but new wood blocks have been cut out and screwed to the underside of
the deck so that they line up with the steel plates welded to the top of the bolster on either side of the
kingpin plate. The deck boards have been screwed back into place. With that, this project is pretty
much finished! The car has been rolled through some switches and will be put into service ASAP.
Just one more thing... although I said I wouldn't paint the trucks, just let them rust...
I don't like the blue springs! So, I will probably shoot some flat black paint on the springs and
sideframes, just to make them disappear into the darkness under the car.
Until then, here is #5121 ready for service with new archbar trucks:
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#5121 with new archbar trucks, in service:
A little black spray paint helped the blue springs and trucks disappear under the flatcar.
By now, the car has had a few trips over the railroad to make sure the new trucks work OK.
With the seats in place, the flatcar is ready for passenger service, or the seats can be removed if
it is needed for freight. Either way, it can easily carry heavier loads than before.
I hope you enjoyed this detailed look at building some simple trucks!