Switching the wires shouldn’t be necessary. Under DC control, “forward” and “reverse” are relative to the track, not the way the locomotive is facing. If you turn the engine around, you’d find it runs the “right way.” Likewise, if you switch the wires, next time you turn the engine around you’d find it running “backward” again. Just think of that little switch on your power pack as “this way” and “the other” instead of “forward” and “reverse” and you’ll do fine. [:D]
Actually, you do need to switch the wires - - but not “under the hood” of your locomotive. You need to switch the wires on the terminals on your power pack.
Believe the important point is that the if the loco in question moves to the right while all other locos on the track move to the left, or vice-versa, then the loco in question is miswired. If all locos move in the same direction then, as suggested, turning the loco in question around would fix things.
Actually, there is an NMRA standard on direction. It reads something like with the left hand rail positive and the right hand rail negative the locomotive shall move forward. If you really care, you can find the NMRA standard at the NMRA website, read it very carefully and check things out. The standard only becomes important when you are doing things like running an ABBA consist of hood diesels, all units powered, and you really do need all four locomotives to move in the same direction. If the B units try to go one way and the A units the other, nothing good will happen.
HO manufacturers are pretty good about getting electrical polarity and direction of motion right, I’ve never had a factory locomotive run backward. I would be reluctant to go about switching motor wires inside the locomotive unless I was VERY sure I had it right. As long as you are only running a single locomotive, you can make the locomotive’s notion of forward and reverse match the legends on your power pack by either switching the wires between track and power pack, or simply placing the locomotive on the track facing in the opposite direction. Once you are double heading locomotives, as long as they all run in the same direction, you are good.
If this loco is different from your others, switch the wires in the loco. If ALL locos run the opposite way the direction switch is labeled, reverse the wires at the power pack.
I have the same problem with a S2 switcher from proto 2k.
Fact is: switching wires on the powerpack is just like switching the direction switch, problem stays. So, not being good at opening delicate locomotive shells I just use my switcher alone, while no other trains are running on other blocks. DC speaking, of course.
If you have other locomotives and they all run the way that you think they should, then your latest acquisition needs to have the wires switched.
I worked on a brass steam locomotive for a friend, adding all-wheel pick-up, and while it was wired backwards to the NMRA standards, it still ran the same as all of my own locomotives. As work progressed, I discovered that a previous owner must have had the drivers out of the frame and re-assembled them flipped left-to-right. Then, as a simpler fix than re-doing it right, they simply turned the tender trucks and moved the wire on the motor to the other brush.
When I took it apart to rectify the situation, I discovered the probable reason for the original disassembly: most of the driver tires were loose on their wheels. The flipping wouldn’t have cured the problem, so I suspect that it was simply a quick re-assembly to get it somewhat saleable. Fortunately, since the all-wheel pick-up puts wipers on the driver tires, it caused no problems to use ca to affix the tires to the wheels, even though it makes both sides of the tires insulated from the frame.
Atheran locomotives used to be Truck Sensitive. If you switched the trucks fore and aft, then the locomotives would run in the opposite direcdtion.
TAKE A LOOK AT THE LOCOMOTIVE… Find the F on the frame of the locomotive. THAT is the Front. Sometimes the front of the locomotive is not where you think it is. Some roads run locomotives long hood forward, others the short hood forward.
Thus trains should not run in the same direction if you have them pointed the same way.
The engine in question appears to be an F unit possibly an E unit.
As Steve Otte said “forward” and “reverse” are relative terms.
I’m thinking you want all of your locos facing in the same direction to all move in that relative direction.
When I ran DC I setup the track polarity to match the position of the switch on the power pack with the direction of travel.
If the direction switch was to the left (<) I wanted the trains to move from right TO left <<<<. If the switch was to the right (>) I wanted the trains to run from left TO right >>>.
To change the overall direction relative to the direction switch on the power pack, switch the wires feeding the track.
From what you’re describing when the direction switch is in one position the locomotive you just purchased runs opposite to relative to the others when facing in the same direction.
In my last post to you I talked about consisting. With F units it was prototypical to run the lead unit “forward” and the second unit “backwards.” When the train arrived at it’s final destination this tail to tail configuration meant that the crew simply switched to the unit facing in the other direction and that became the lead unit without having to physically turn the engines around with a turntable.
I suspect that the previous owner might have wired this loco for this type of MU’d operation by either switching trucks front-to-back or re-soldering the motor connections.
If it was manufactured overseas the polarity might not have been wired to the NMRA standard.
Who Knows???
Once you have determined which way is “forward” on your pike (mine is clockwise) set up the track polarity so that the direction switch represents this with the bulk of your locomotives.
If you have any that run “backward” relative to the others this is the one
That i did before without knowing it will happen and you can take the Athearn motor apart and rotate the middle and the same will happen a great way to have a head on if you run DC only.
Ah, the AHM C-LINER! I’ve had plenty of experience with these. If it’s running in the opposite direction from anything else you own, switch the two wires on the motor around. They should be soldered to clips, so it’s a simple matter of popping them off and switching them.
Not unlikely. You have to read the NMRA standard very carefully and make sure you understand what they mean by forward and backward, left hand and right hand, and some other stuff. And it’s still easy to get it wrong. For myself, until I have units in a consist, running in opposite derections, I would avoid messing with the insides of locomotives. If all the locomotives in a consist run in the same direction, all is well.
I didn’t bother to read the NMRA standard befoe posting, I just quoted from memory to give a feel for the issues it addresses.
If the engine runs left while all the others run right, the wiring on the loco is switched. Reversing the wires will fix the problem.
Is it a used loco? Some model railroaders reverse the wires on a few of their locos because a loco running “backwards” is usefull in their their operations.
The wiring does not have to be reversed to MU in DC. NMRA standard is if the engineer’s side (right) rail is positive, the loco runs forward, which with a cab unit is obvious, with a hood unit, look for the F because some railroads run long hood forward and some ran short hood forward, most these days is short hood forward. Then there are the ringers - where the prototype was dual control, so the label on the frame would be F1 and F2. Which one is the Front Front? Pick one.
Now, if you have a loco, say an F unit, and it is facing to the right, and moves forward when the right hand rail is positive, perfect. Now take that loco and pick it up and put it back in the rails facing left. Now the left hand rail, relative to the position of the engineer, is positive, and the loco should run backwards. So to couple a pair of F7 A units back to back, no rewiring is needed.
That’s the way they SHOULD work. Altered gearing, or a motor replacement that was hooked up backwards, or a loco just designed to run the “wrong way” per prototype, will affect this. I never tried one of my P2K Geeps on DC power, but Reading ran them long hood forward. P2K has the F on the end of the long hood, correctly, but with a DCC decoder plugged in in the proper orientation, forward moves them short hood forward (and they have the crew figures facing the short hood!). I suspect that on DC they will do the same, the ‘forward’ direction will be towards the short hood instead of the long hood. Fixing that simply means reversing the motor wires.