Broadway Limited J9000 4-12-2 - Video


Sounds like you got it squared away. Like the last video. Reminds me of riding in the some car on the North Coast Limited.
 
I took my J9000 apart tonight to see what the inside looked like. It seemed to be binding but I couldn't see any problems on the outside. The motor has a single flywheel that isn't much weight at all. I don't think there would be much difference if there wasn't a flywheel. The motor links to a gear tower that is over the third axle from the rear. The side rods are what turn the rest of the drive wheels. I had disconnected the tender from the loco to disassemble it and that gave me some insight to the electrical and mechanical connections. The draw bar seems to have some spring action to it. I pulled the draw bar pocket out of the tender and opened it up. There is no electrical function to it, just a mechanical spring action. Some thought that the spring action may be a sensor point for the load detection for the decoder. The boiler body and cab disconnects from the frame by removing the single screw that holds the front wheel truck in place and the two rear facing screws on each side of the 8 pin socket. Ya have to wiggle it a bit to separate the two pieces. I added some nano lube to all the axles and drive rod connectors. I also added it to the motor bearings and gear tower. I connected a 9 volt battery to the motor to run the nano lube in for a few minutes. I notices some squeaking went away that was present before. While I had that apart, I pulled the tender apart too. Inside, there are two 1" speakers. The decoder is mounted on the ceiling of the tender with the speakers mounted below it, facing down. The wire harness can be pulled out of the forward facing slot toward the loco to move it out of the way for installing weight. The two trucks of the tender provide electrical pickup for the model but only the front and rear axle of each truck pickup. Two wheels on the left, two on the right. The drive wheels on the engine provide right and left pickups and is routed to the decoder in the tender through the electrical plug. The wire harness, when connected to the loco may cause the front of the tender to be slightly lifted off the track. I would recommend adding some weight inside the tender at the front to keep good electrical contact with the track. There is plenty of room in there for weight to be glued against the sides of the tender. I will reassemble the tender in the morning and run it on the layout.
 
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BEMF can detect motor stresses, such as going up hill the engine would slow down, but the BEMF gets that and applies more power and equalizes the speed, same for downhill, speeding up it will cut back on the power. Putting a microcomputer into the mix (decoder sized) has gotten decoders to do simulated throttling (synthesized, like synthesizers make sound, a synthesized throttlling simulates real world throttling) Its hard for me to believe the tender is the only pickup, the engine has to power pickup as well. I'll look for these on mine when I get it. Are the drivers positioned in "thirds" than "quartered"?
I'm just thinking about the siderod issues and not having problematic powering sync being on a third. You can never see both sides of the engine at once you could easily make them in a quarter making sure there is no sync problem. The prototype would not do that, it would be in a third but they would have some system to keep the drivers in check. BTW the QSI Titan decoder is amazing, it needs no cam for the chuffs, it calculates the motor revs and syncs the chuffs perfectly. The Huuuuge manual for it describes a lot about its throttling and how to tinker with it.
 
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That frame connect seems to be very similar to some brass engine standards. They're making some pretty good tight fitters today, because of the high degree of technology in it. Their 4-4-4-4 tender has ZERO screws, all a tight fit, pull it correctly.
 
Instead of adding weight to the tender, which IS a reasonable option, why not just ream out the draw bar hole a couple of thou with a suitable Dremel bit and smear a tiny dab of white grease around the tender's post? Also, after connecting the tether to the locomotive's socket, try to shove some of the wire back into the tender. The more wire left out and in a tight bundle, the worse the tracking for the tender.
 
The draw bar between the tender and engine isn't a pin. It's more of a slot in the bar on the engine and a tab on the bar from the tender.

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