Repairing Rivarossi Cab-Forward Engine

[nitratefury]

Hello, fellow train folk! At our train club, my son uncovered an early Rivarossi Cab Foward engine that is currently not running. I brought it home and confirmed that both motor and drivetrain are functional. What is missing is whatever parts connect the drivetrain to the motor. I attach a picture showing what we have—can someone tell me what’s missing? I’m guessing one piece is the hard black plastic tube that is used to join turning parts together. But what meshes with the gear that comes right off the motor?

 

[logandsawman]

Check this out:

You can find more diagrams on HO seeker : https://www.hoseeker.com/ahminstructions.html

There are different diagrams depending on the year of mfg.

Dave LASM

 

[MikeGTW]

I don't think that motor belongs on that engine None of them used a open face gear like that The motor should have a half flat to work with a coupling part 67 in that diagram If you can't find one you could use a can motor
A old friend of mine Mel Perry rebuilt a few cab forwards He passed away in June of 22
He and I redid several athearn bb engines ran better then ever
here's a link to his blog about those cab forwards

http://melvineperry.blogspot.com/2019/11/rivarossi-cab-forward-motor-replacement.html

 

[bnsf971]

That’s a standard Rivarossi 3 pole motor.
What’s not standard is that brass gear on it.
It looks like somebody was trying to put in some kind of reduction gear to get better low speed performance.
What should be there is a plastic shaft similar to the one between drive towers.

 

[Iron Horseman]

I attach a picture showing what we have—can someone tell me what’s missing? I’m guessing one piece is the hard black plastic tube that is used to join turning parts together. But what meshes with the gear that comes right off the motor?

Totally agree with the others. That is not a stock arrangement for any of the years that locomotive was produced by either AHM or Rivarossi.

If there is enough shaft once the gear is removed normally I would say that a short piece of fuel line would work. But I also have to say some things from the the photo. One, it looks like they have modified the shaft out of the gearbox with a notch for some specific connector. Don't know if a fuel line can bite it tightly enough. Then, It looks like the angle from motor shaft to the gear box is, umm, awkward. Motor mount is not stock, so looks like it needs to be shifted to align better with gear box shaft.

 

[MikeGTW]

That shaft fom the gearbox does have that notch in it to connect to the plastic shaft piece #67 The motor shaft should have the same notch
He may never find the right motor and even so those 3 pole motors wern't the best

 

[Smylietom]

Sorry for joining so late, but that is actually a stock setup. I bought one in 1979 and it was setup the same way. Later on the did away with the gear box.
MikeGTW; I would like to connect when you have time to talk about how you modified the zinc weight to repower. I have a couple Cab forwards that have a solid zinc mounting for the motor. I would assume that it would need to be cutoff to place a new motor. I wondered if you had any of Mels old pictures.

 

[Iron Horseman]

Sorry for joining so late, but that is actually a stock setup. I bought one in 1979 and it was setup the same way.

Interesting. That configuration is not in any of the "blueprints" on HO SEEKERS. You wouldn't happen to have the doc that could be uploaded to them do you?

 

[Smylietom]

Unfortunately I don't. I have been looking but the only one I have found is the one above by HO Seekers. There also seems to be another configuration with a solid mount where the tender is not required. The one in the pictures above that I posted came in a plastic case bought in 1978 or 1979 just after I graduated from University.
I have attached two pictures of different Rivarossi Cab Forwards that have the solid mount, which do not require the tender to run. There is no wire on the connector where the tender attaches to the engine. Incidentally if anyone has a source for the zinc weight that is pictured, please let me know. The one in the picture appears to have been affected by "zinc mite" from what I have been able to google. It is deformed and the front mount for the drivers is broken. It would be equivalent to number 58 in HO seekers diagram above.

 

[Smudge617]

As Hornby own Rivarossi, have you contacted Hornby USA to see if they could help ?

Or ask on the Hornby International forum.

Hornby International

uk.hornby.com

 

[Smylietom]

As Hornby own Rivarossi, have you contacted Hornby USA to see if they could help ?

Or ask on the Hornby International forum.

Hornby International

uk.hornby.com

Thanks, no I have not, but I will now. Cheers

 

[MikeGTW]

Unfortunately I don't. I have been looking but the only one I have found is the one above by HO Seekers. There also seems to be another configuration with a solid mount where the tender is not required. The one in the pictures above that I posted came in a plastic case bought in 1978 or 1979 just after I graduated from University.
I have attached two pictures of different Rivarossi Cab Forwards that have the solid mount, which do not require the tender to run. There is no wire on the connector where the tender attaches to the engine. Incidentally if anyone has a source for the zinc weight that is pictured, please let me know. The one in the picture appears to have been affected by "zinc mite" from what I have been able to google. It is deformed and the front mount for the drivers is broken. It would be equivalent to number 58 in HO seekers diagram above.

That first one looks to be in bad shape no saving it And that set up on your first one I've never seen before with the gears like that
That last one in the first picture from Mel sure looks like it could have been the same set up He just wanted a can motor
Also I never had a cab forward just a big boy and some others 4-6-4 and a 2-10-2 that i put a Kato can motor in ( 31-500 or HM-5 )
A few others smaller ones It was Mel that did all the cab forwards He made a couple brass frames when one of his went bad