How do I change loco direction?


jasonelki

jasonelki

Milwaukee Roader
Hoping the wiring forum will help me out on this! I've got an old athearn BB GP7/GP9 that runs in the opposite direction of all my other locos. I read the article on "how to upgrade your athearn BB" and while it was mentioned to mark part of the truck prior to taking it apart to keep it running the right way, I haven't a clue how to get it working correctly. I would guess the only way to make this happen is to resolder the wires opposite(as it appears someone "upgraded" this loco awhile back)?
Any help is appreciated!
Not that its a big deal but more curious than anything.:D
thanks!

Oops, forgot about the photo!
 
Last edited by a moderator:
That would be the quickest solution. If it runs well, but backwards when the shell is oriented to all other engines (I assume DC?), then you can reverse both trucks or reverse the wiring at the motor contact and frame, depending on how it is currently wired.

-Crandell
 
You can't reverse the wiring withot minor surgery.

The truck pickup clips pick up a certain side of the rail and it goes to the top clip on the motor. The truck contact with the frame picks up the other side and that goes to the bottom motor clip which has contact to the frame.

If you were to simply reverse the wiring, you'd have a short.

To reverse the wiring, you'd have to take the motor out, isolate the bottom clip from the frame, then wire the trucks to the bottom clip, and add a wire from the frame to the top clip.
 
diburning said:
You can't reverse the wiring withot minor surgery.

The truck pickup clips pick up a certain side of the rail and it goes to the top clip on the motor. The truck contact with the frame picks up the other side and that goes to the bottom motor clip which has contact to the frame.

If you were to simply reverse the wiring, you'd have a short.

To reverse the wiring, you'd have to take the motor out, isolate the bottom clip from the frame, then wire the trucks to the bottom clip, and add a wire from the frame to the top clip.
Click to expand...

Can the contacts coming up from the trucks(I think this is called the L bracket?) be switched to the other side?
Sounds like this might be too much work for what its worth!
 
The easiest way is to change the trucks from one end to the other. I have found this 2 or 3 times from engines I have bought off EBay. Reversing the motor won't help either.
 
You can do what Larry said and move the rear truck to the front and vis versa. Or, I think you can flip the magnets in the motor, I'll have to check but I think I've done it before.
 
Just heat up those solder joints on the top motor clips & remove them, switch the trucks & resolder. Beleive me it's the easiest way. LOL
 
Larry said:
Just heat up those solder joints on the top motor clips & remove them, switch the trucks & resolder. Beleive me it's the easiest way. LOL
Click to expand...


So do I just swap them front to back, or do I need to not only swap them but spin them 180 degrees as well?

Prior to asking in this thread I swapped the worm gears hoping that would fix it. Not so much.
 
The way you have the trucks now, just switch ends. You still have to have the gear facing in the right direction to hook up the driveshaft. What we were talking about was, 180*, means to switch ends.
 
Larry said:
The way you have the trucks now, just switch ends. You still have to have the gear facing in the right direction to hook up the driveshaft. What we were talking about was, 180*, means to switch ends.
Click to expand...

I really should have had the loco in hand prior to my last post. For some reason I thought you could just spin the truck around where it was, but it doesn't work that way!

Project complete, just swapped front to back.
Took longer to warm up the soldering iron than to do the job!

Thanks for the info!

Maybe someday I'll make some upgrades to this unit, until then I'll keep my eyes open for a Proto Milwaukee Road GP7 or GP9! Train show in a couple weeks in Madison:D
 
You must log in or register to reply here.



Back
Top