Rivarossi N-scale Big Boy repair help

My local hobby shop sometimes asks for me to help on repairs that have them
stumped, and as a retired electrical engineer/nuclear submariner/hack
machinist, I've usually been able to help. Last weekend, they asked me if I
would tackle a Rivarossi N-scale Big Boy that is mechanically frozen. I can
see what would seem to be the problems - one rear driver on the front engine
free-wheels on the axle, a couple side rods with the sloppy 'U' ends are
loose from the respective main crank pins, and 3 of the driver sets are
rotationally out of sync with the other 5. My problem is holding the
drivers that are correctly aligned into the frame, while keeping the open
ended siderods in place on the main crank pins, and rotating the remaining
drivers into place against the idler gears so they are in proper sync when
seated in the axle slots. I've tried a half dozen times without success.
When I get the parts all together, it seems one driver set is always
misaligned with the rest and the chassis will not roll freely. Does anyone
know the trick to fixing these #%^$*&)!@$ things? Gary Q
Reply to
Loading thread data ...
Nope, no tricks...
All the old Rivarossi designed steam locos have this strange design where all the drivers are geared and linked via siderods at the same time. And the gears have plenty of play in them too!
Honestly, I've fixed similar locos and I just "played" around aligning the gears until they finally fell into alignment. You might have some luck trying to skip a tooth ahead or behind when placing the driver back in its place. It is a royal pain especially with all the idler gears in the way!
I suspect that when they assembled them in the factory, they had some sort of a jig and I'm pretty sure that they siderods were not applied until the drivers were all locked in place and aligned.
Good luck! Peteski
Reply to
Peter W.
On a second reading I see that it is even more serious than I thought.
If the drivers freewheel on the geared axle, it will be almost impossible to get them back into the designed locations (and glue them somehow).
You might have better luck finding a parts locomotive and just replacing the entire "engine" assembly.
I think Con-Cor still sells the replacement parts.
Reply to
Peter W.
Hiya, I was wondering after reading your post if the drivers are in quarter. Yes I know they are geared but........if one of the drivers has slipped out of quarter..............OUCH! I never understood why they made those articulateds so sloppy in the gearing dept.
Reply to
John Franklin
Peter and John - Thanks!! I finally got it together and it seems to run OK. I wound up making a cradle to hold each engine upsidedown in a vise while I worked on it, and made a thin weight to rest on top of the driver and idler gears that were aligned to hold them from popping out while I inserted the remaining drivers. I lightly pinched the end of the axle with the loose driver with the tip of a sharp new set of diagonal cutters to upset the factory knurl a bit and then for good measure added some LocTite Green as I seated the loose driver while in eye-ball quarter. I think I also dredged up every cuss word I ever heard in 30 years USN/USNR. Thanks again for your comments. Gary Q
Reply to
Good job Gary! :-) Peteski
Reply to
Peter W.
Dear Sir:
Obviously, the cuss words are what allowed you to fix it. This is more proof of my theory that salty language creates unique vibrations which:
-Loosen rusted fasteners
-Increase human muscular strength
-Dull the pain receptors of the nervous system.
-Even out variations in muscle contraction (allowing you to keep a steadier hand when placing obnoxiously tricky components)
I have conducted substantial lab work on various failed mechanical devices...
Cordially yours, Gerard P.
Reply to
Obviously, the cuss words are what allowed you to fix it. This is more proof of my theory that salty language creates unique vibrations *** -------------------------------------------------- I often use "salty language" to undo mistakes I've made. I find that it also rectifies things I forgot to do.
Bill Bill's Railroad Empire N Scale Model Railroad:
formatting link
History of N Scale:
formatting link
Railroad Bookstore:
formatting link
to 1,100 sites:
formatting link
Reply to

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.