Hi folks. I have an Atlas GP9 and a Kato RS2, both of which run very well! However, they run in opposite directions on the track? There are no wires to reverse in these... ideas? I am quite stumped!
If it they are not DCC but DC one of the motors has been put in with the contacts reversed. Most likely candidate is the RS unit. Simple fix to disasseble the frame halves and simply turn the motor over.
If it's DC, borrow a third locomotive to break the tie, otherwise you'll possibly end up with two wrongs by accident. One of the two is wrong on the motor orientation in the frame, but without an electrical meter to check rail polarity vs. direction, you're kind of in a heads/tails dilemma.
I do have a meter, and yes, they are DC. How should they run? I do have a third loco on the way, but as it's coming from Canada, it will be a bit.
Have you had any of them disassembled and the motor out? If that is the case then that is the one. I have had more than a few apart over the years and I have reinstalled a motor back in wrong way before, then got in the habit to take a marker so I could mark the correct orientation. Maybe a simple test is to use the power pack and with a locomotive set on the tracks engage the throttle for forward. The locomotive that moves forward is right while the locomotive that moves in reverse is the one you need to turn the motor over in. Not rocket science but just an easy way to diagnose.
This is the Kato RS2's motor. Looks like a real strong suspect for accidentally installing it rotated (about the motor axis) 180 degrees.
Another question is what do you mean "backwards"? Depending on the railroad, the GP9 could run forwards as "long hood forward" or "short hood forward". As this is the Atlas GP9, I have seen the shells installed to try to be "faithful" to the road, and they are completely reversible. George (@mtntrainman ) was kidding, but the solution could be just that easy - flip the shell.
It is possible for the Atlas GP9 shell to fit on the frame in either direction. The correct orientation would have the air tanks next to the fuel tank under the long hood end.
With the right hand rail positive, the loco should move forward. It's one of the oldest standards in two rail model railroading. Doug
Doug - in the interest of avoiding (further) confusion in this thread, let's be more specific. If you are looking at the side of a locomotive, and the rail closest to you is positive, are you suggesting that the loco should move to the left or right?
Look on the shell for an "F" around the walkway level. That's the forward end. As RBrodzinsky said, some roads run long hood forward, others short hood.
Right. If the farther rail is positive, it moves left. But regardless, if the front of the loco is pointed in either direction, if the rail on the loco's right is positive, the loco moves forward, from the loco's perspective. Doug
This is becoming almost comedic..... There is a standard in two rail DC, and it doesn't matter if the locomotive has a cab on one end, cabs on both ends (GG1), F markings or no shell whatsoever. If the motor is installed per standard practice, the mechanism will move in a specified direction based upon polarity of the track. I think Doug captured it (but then perhaps re-confused the audience by mentioning "forward, from the loco's perspective.") Back on topic. The OP apparently has a loco mechanism that will allow the motor to be (mis)installed in a manner that will reverse its polarity. Most mechanisms won't allow this, but based upon the photo I posted of the Kato RS-2 motor, it could easily happen.
Confusion reigns anytime this subject is broached. Some older locomotives made it easy to determine the motor orientation (the mounting hole being threaded or the motor frame only fitting one way in the loco frame) but there have been many throughout N scale history which are easy to mix up. The old original Atlas/Rivarossi E8 or FM, for instance (or actually, any of the Rivarossi locos using that motor). The can motor will fit either way 'round even though the slots to mount the plastic motor cover are different shapes on the bottom to indicate the correct orientation. A typical user, having removed the motor, will most likely never see those different shapes and will randomly get the motor in wrong. But, back to the original subject, all you have to do is decide which is the front of your loco and make sure the rail on the right is positive to get it to move in that direction. If it doesn't, either wiring or motor orientation is incorrect. Doug
People, people, people. His locomotives are trying to have a tug of war. It doesn't matter which way the locomotive is facing. That's irrelevant. If the near rail is positive, it should move left to right, and if the far rail is positive, right to left. Regardless of which way it's facing, if it's moving away from you the right hand rail should be positive. If it's moving toward you, it should be the left hand rail. That is what Doug said. Once they're straightened out, they'll both go the same direction together whether tail-to-tail, nose-to-tail like elephants, or even nose to nose. I'm an HO guy and not familiar with these particular units, but swapping trucks end-to-end can create this problem too. Generally one side of each truck connects directly to ground through the frame and the other is carried by a wire. On an all-wheel-drive unit you can't connect the worm to the flywheel when you put the trucks in backwards, so you assume you did it right. But if you put the front truck in the back and vice versa, you've reversed polarity.
Yes, that is also true. Anything that changes the polarity one way or the other, will affect which way the loco moves on the track. If you take your two locos and face them so the front of the locos are facing left and the farther rail is positive and one moves to the left and the other one moves to the right, the one that moves to the right is wrong. And speaking of HO, I finally found, after months of waiting, a boiler front for my Rivarossi 0-4-0 with tender! I bought it last year and that part was missing, the rest being excellent. What is it about boiler fronts and people losing them? Doug
Doug - why are you still confusing the issue with "front of the locos are facing left?" It doesn't matter! I know that you know this from your posts.
