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Discussion Starter · #1 ·
My friend acquired a Rivarossi UP Big Boy and SP Cab forward locomotive (probably from the 1970's or 80's), but he's having some issues. He wasn't able to get the tenders for them, and neither of them will run even though the motors are in the locomotive. He actually hooked up an MDC Roundhouse tender to the Cab forward and it ran, but the Big Boy still didn't run with it hooked up. My questions are, why would the Cab forward run with an MDC Roundhouse tender hooked up, but not without a tender? Is there anything that can be done to get them to run without tenders? We're also not sure if the Big Boy is supposed to work without a tender or not.
 

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There is probably electrical pick-up wheels in the tender, and the current runs to the motor through the draw-bar….
 

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Every steam Rivarossi I have had has electrical pickup through the tender, no tender, no power to motor. Have not owned the big boy but would be surprised if it was different
 

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I remotored my 70's Cab Forward, with a faulhaber 12v coreless. I added a Soundtraxx decoder. I putthe decoder and speaker in the tender, and like said above, the tender is an electrical pick up. Your Bowser tender should work with both, but you need to check the polarity of the tender's electrical pick up. That may be why it works on one and not the other. You can also use a multi meter to see which side of the locomotive and tender has pick up. Then with out the tender, with the locomotive laying in a cradle, touch one wire from the transformer to the draw bar and the other to the drive wheels.
 

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I have a cab forward and yes, the tender provides power from one rail. there's a thin wire on the bar joining loco and tender, and the tender has a metal pin wired to the trucks which pick up power from brushes. Mine was missing the tender too so I bought a shell off epay and had a spare pair of trucks.
Your big boy is probably either missing the thin wire or something isn't connected right. Also, the contact between the wire and tender needs to be solid, I always push the wire across the hole with the pin when joining them so (hopefully) it's under a little tension.
 

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What is the Number on the Big Boy and when you have it on the track is it getting power? As far as I know the Big Boy & Challengers didn't need the Tender with power pickups to run. Go through your progressions on wheel cleaning especially Front Pilot on the Big Boy. Check your drivers for kinks do they move freely and especially with age how it is lubricated. Old grease that dries out can bind your gears. Go on YouTube and there are some excellent video on maintaining these terrific locos. I have a fleet of Berkshires, Challengers and my 2 Big boys and once you get them running will really feel great!!
 

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Discussion Starter · #7 ·
What is the Number on the Big Boy and when you have it on the track is it getting power? As far as I know the Big Boy & Challengers didn't need the Tender with power pickups to run. Go through your progressions on wheel cleaning especially Front Pilot on the Big Boy. Check your drivers for kinks do they move freely and especially with age how it is lubricated. Old grease that dries out can bind your gears. Go on YouTube and there are some excellent video on maintaining these terrific locos. I have a fleet of Berkshires, Challengers and my 2 Big boys and once you get them running will really feel great!!
It's 4005. The headlight comes on dimly so seems like it's getting power.
 

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It's 4005. The headlight comes on dimly so seems like it's getting power.
Well that in fact is a good sign. I can't grind on this enough.... Check the wheels again for dirt/grime and clean your track again..use a Bright Boy Eraser, Isopropyl Alcohol on the track & Wheels, a clean dry rag to wipe both off with or cotton swab..making sure you don't get fibers in the gear box or motor. Put the Big Boy on the clean track and put your transformer on very low speed...sometimes these old Locos are just grumpy and the motor needs some warmth. Do Not give it full power if it does start to move...let her settle in. Like I said there are some video's on YouTube that can be very helpful. Let us know how it is progressing and good luck!
 

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Discussion Starter · #9 ·
Well that in fact is a good sign. I can't grind on this enough.... Check the wheels again for dirt/grime and clean your track again..use a Bright Boy Eraser, Isopropyl Alcohol on the track & Wheels, a clean dry rag to wipe both off with or cotton swab..making sure you don't get fibers in the gear box or motor. Put the Big Boy on the clean track and put your transformer on very low speed...sometimes these old Locos are just grumpy and the motor needs some warmth. Do Not give it full power if it does start to move...let her settle in. Like I said there are some video's on YouTube that can be very helpful. Let us know how it is progressing and good luck!
He did those things. He was getting full power to the motor but it still wasn't doing anything. He thinks the motor windings are fried so he's going to get a new motor.
 

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Did you guys take a look at the motor itself...can be a pain with articulated Rivarossi but take your time and that motor could be salvageable as they are built tough...or just remotor 🤣 🤣 🤣 (y) Love opening up these old steamers and seeing how they are built and why they last so long. Good luck and keep us posted that Big Boy is something else. Are you guys doing a Layout together as well...hey take some pictures and post them as well!!(y)
 

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Discussion Starter · #11 ·
Did you guys take a look at the motor itself...can be a pain with articulated Rivarossi but take your time and that motor could be salvageable as they are built tough...or just remotor 🤣 🤣 🤣 (y) Love opening up these old steamers and seeing how they are built and why they last so long. Good luck and keep us posted that Big Boy is something else. Are you guys doing a Layout together as well...hey take some pictures and post them as well!!(y)
He's doing all of the work, I am just doing research for him. I am not sure if he has the knowledge to salvage the motor; I know I definitely don't. He sounds pretty set on getting a new motor. Nope we're not doing a layout together. He has a pretty full house with two kids, and he already has a combination standard/O gauge layout in the basement. His HO track is just an oval on a small table. Plus he is into older trains; he has no DCC. Mine are are newer and mostly DCC.

I've attached the picture sent me, one of them after he removed the motor.
 

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I have one of these older Rivarossi/AHM Big Boys with the cab motor, too. Mine had the round motor (looks like a can motor but still uses the pancake style round peg brushes). It doesn’t need the tender to run, but seems to be wired such that the front wheel set picks up power on one rail and the rear set picks up on the other rail.

Mine also needed some wake-up work when I got it. As another post above mentioned, what I found was one of the two 90-deg gearboxes had dried grease in the brass gears that was binding up the drivetrain, while the other one was fine. Once I cleaned it all up and re-lubed everything, it started to run.

The motor ended up being pretty weak (with age? wear?), so I also ended up upgrading the motor to the Canon EN22 (if I remember that correctly), and it still runs great. Best of luck to your friend!
 
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