Question about broken truck

[Maletrain]

I bought a Roundhouse 50' Wood-sheathd express reefer on eBay, and it arrived with one side fram of one truck broken off at the bolster center area.

Does anybody have experience trying to repair a break like that?  I am not sure what sort of plastic is used by Roundhouse back in the day that these trucks were made.  If it is Delrin, I am not expecting to be able to make that truck useable again.

But, if it is a weldable or glueable (with epoxy) type material, maybe I can fix it.

So, has anybody here successfully repaired a Roundhouse truck like this, before?

[CBQ Fan]

 I would replace it with a Micro Trains truck.

[brokemoto]

I bought a Roundhouse 50' Wood-sheathd express reefer on eBay, and it arrived with one side fram of one truck broken off at the bolster center area.

I would follow the advice of @CBQ Fan .  It is what I did,  I used four wheel passenger trucks.  As a result, I  have more than a few extra original trucks.  MT does sell Commonwealth BX Express Trucks, but they do seem a bit small for the car.

If you want a pair of the original trucks, send me a PM.  They probably are missing couplers and some wheels, but, if you do need the wheels and original Rapidos, I can find some and replace them or simply put them into the package.  Let me know.

[thomasjmdavis]

The MTL truck is more "modern" than the Roundhouse truck.  But if you are modeling any time after about 1910, it is probably at least as correct, maybe more correct, than the Roundhouse.  The Roundhouse truck was also used under their "Overland" 55' cars (not to be confused with their "Overton" 34' cars), which are 1880s (?) era, and has the look of a wood beam or very early steel truck. (my opinion, anyway)  Although now that I think about it, my Overland cars were purchased 2nd hand, so I can only say those are the trucks on my Overland cars.

The other options that occur to me are the trucks that Athearn used under their 40' milk cars- which are shorter, but still of "express car" design.  I'm not sure about availability, but Spookshow lists a catalog number.
http://www.spookshow.net/trucks/cwexpress.html

Apparently (although I've never seen it in person), IMRC also makes a Symington-Gould express truck (which looks like a freight truck, only bigger).
http://www.spookshow.net/trucks/symington.html

[sd45elect2000]

Fine N scale products sells the identical trucks for their REA car kit. I think they are metal though.

Randy

[Lemosteam]

Drill a little oversize for a short piece of phosphor bronze wire, 0.010" diameter or something, in the approximate middle of the broken cross section on both parts. Use some UV glue on both parts in the hole and on the wire.  Hold them together, wick off excess glue with the edge of a tissue, make sure it is set where you want it and hit it with the UV light.  I like the JB Weld version of this glue very much.

[peteski]

IIRC, those trucks are made from the typical  slippery plastic (like Delrin).  Just as a test take some solvent glue (like MEK acetone, or Methylene Chloride) and dab a little drop on some hidden part of the truck (like under the bolster) and see if it has any effect on the plastic.  I doubt it.  That type of plastic is is also difficult to glue since nothing really bonds well to it, and you need decent bond for those parts to stay together.

I like John's ideal of pinning the broken parts together, but I have no trust in any UV glue (I'll be finally ordering some of it today as neither local Home depot or Ace hardware had any in stock).  I would the weld the broken parts together using a soldering iron,  That is the only way I found to produce strong repair in that type of plastic.

I'm also unclear on the description of the break.  Is the sideframe broken off at the end of the bolster, or the bolster itself is broken into 2 at the hole for the kingpin?

[Maletrain]

Thanks for all of the ideas, guys!

I looked into the other truck options, and compared the similar trucks that I currently have on hand.  The Overland and Atlas shorty and Bachmann shorty trucks look similar enough, but I don't have spares of any of those.  The MicroTrains trucks look substantially different.

The break is where the bolster reaches the circular section around the hole, so the hole is intact, and the angle between the side frame and the bolster is intact.

For the truck repair to make it functional, I will need to make what is basically a thin butt joint across the boslster be flat, and resist flexing forces.  Not sure what could do that to a sufficient degree.  Putting pins in the joint would help with shear forcess, but not much for bending forces, except maybe phosphor bronze wire. like Lemosteam suggested.  I do have some to try.

I will try some solvents on the material today and see if that does anything.  I have acetone, MEK and ethyl chloride.  At least I have suitable substitutes if (when?) I make a total mess of this part.

[peteski]

Could you post a photo of the broken truck?

[Maletrain]

Well, methylene chloride had no effect on the plastic.

And, trying to hold the 2 pieces in the right position is really difficult, because there aren't corresponding flat surfaces on opposite sides of the break for easy alignment.  And alignment needs to be good for a truck, so that all wheels contact the rails and the bolster is level.

The repair seems like doing it right would require a microjig to hold the pieces and then a steady hand to do melt welding with an iron.  And, then it could still break when I insert the wheels.  Oddly, the OEM axles measure 0.548" and 0.549". ESM 0.553" axles roll nicely in the intact truck, with about zero side-play.

So, I am going the replacement route. 

Just to show folks where the break occurred, I am attaching a quick and crappy cell phone pic.  To really show the lack of easy alignment surfaces, I would need to dig out the macro lens, tripod and lights.  Not worth my time or yours.

[ Guests cannot view attachments ]

The easy way seems to be to take brokemoto's offer and get another OEM part from his parts drawer - and I really appreaciate the opportunity for an easy solution.

Great to have a support group like TRW!

[peteski]

Yes, I agree that a jig would have to be built to keep the parts inc correct alignment.  I would then take  couple of short pieces of 0.010" phosphor bronze wire, and using a soldering iron melt then into the parts creating embedded splints. Then I would probably do some more "welding" around the broken pieces.  Yes, it would be a fairly precision task.

Finding replacement trucks sounds like a good solution.

[nkalanaga]

My solution is to use a razor saw to cut vertical slots in the two pieces and glue a matching piece of brass or aluminum in the slots.  Once the truck is on the car there shouldn't be much stress on it, so ACC should hold, with a good, tight mechanical joint.

To make sure the slots line up right, fit the two pieces together, pin them to a piece of wood, foam, or whatever you have that will hold pins, and scribe a line across the joint, where you want to cut.

But, yes, replacing the entire truck is probably the best bet, since a replacement is available!  After it's installed, you might want to try one or more of the suggestions on the broken one, to see if they work for you, in case you ever need them.

[Maletrain]

In order to do any of the suggested fixes, and come out with a truck that is level side-to-side as well as front to back (so that all wheels reach the track and the car does not lean to the side), it would be essential to make a jig that holds the 2 pieces in perfect alignment.  And that jig would need to be very rigid to deal with the forces of cutting, welding or whatever.  Plus, the upper surface by the bolster pivot point needs to remain unblemished by the fix process.

The only way I can see to do all that is to make a metal support that gets all of the pieces to the correct elevation off the work surface, which would probably require some milling of the support surfaces to get the proper off-sets between the bolster arm and the pivot point support surface and the top of the truck frame, which are not flat across.

In theory, I guess I could do all that.  But, to resurrect a cheap, replaceable truck - why bother?  I have other challenging things to try to make that I can't just buy somewhere, and not enough lifetime left to make everything I want.

[peteski]

In theory, I guess I could do all that.  But, to resurrect a cheap, replaceable truck - why bother?  I have other challenging things to try to make that I can't just buy somewhere, and not enough lifetime left to make everything I want.

You asked for possible fixes, and were presented with several more or less workable options (one of them was to get another unbroken truck).  What you chose sounds like a win all around.

[Maletrain]

Thanks, everybody.  Brokemoto's care package arrived this morning, and I swapped in the coupler and added ESM wheels.  All is good and rolls really freely.

When I decide what couplers I want to standardize, I will swap those out.  Basically waiting to see if the Npossible or Protomate couplers get into production and the mainstream, so that I can expect continued availability