DCC Santa Fe Loco not moving

[BuzzRickson]

I have a Santa Fe locomotive that connects to the track and receives power but can barely move - very sluggishly. I took the shell off to inspect it and while doing so I noticed a small black rod that was jammed in between the wheel and the wheel cover. Thinking this was my problem, I pulled it out and re-ran the train but there was no improvement. I think the rod may actually be part of the transmission assembly and somehow fell out through the axle connection area. It’s hard to inspect the guts of the loco because of the top circuit board. Here’s a picture of the black rod I’m talking about.

 

[gabby]

That looks like part of the drive train from the motor to the bogies

I guess you will have to take it apart and see which end it belongs to

 

[BuzzRickson]

That looks like part of the drive train from the motor to the bogies

I guess you will have to take it apart and see which end it belongs to

When I took it apart I could see that the rear one was in place. This one came from the front. I just can’t get into the chassis area since the circuit board is blocking it.

 

[flyboy2610]

You'll need to remove the circuit board. It may clip on or use screws. You shouldn't have to remove any wires, but if you do make careful note of where they go. You may wind up having to remove the upper gear tower clip to allow the driveshaft to slide back onto the universal joint. Once you get the circuit board moved aside you'll see what I mean.

 

[D&J RailRoad]

Most likely the top clip to the driven truck has come loose and allowed the worm gear to lift up.

 

[BuzzRickson]

You'll need to remove the circuit board. It may clip on or use screws. You shouldn't have to remove any wires, but if you do make careful note of where they go. You may wind up having to remove the upper gear tower clip to allow the driveshaft to slide back onto the universal joint. Once you get the circuit board moved aside you'll see what I mean.

So I was able to just barely work around the bread board and loosen the gear tower screw. I found the universal joint had slipped off the worm gear. I was able to get the joint back on the worm gear and slid the driveshaft back into the joint. Everything looked fine but it’s still encountering the same problem when I try to run it. One thing I noticed is that the universal joint on the motor side could be easily rotated manually which doesn’t make sense because I would think the motor should put up a lot of resistance. So now I’m thinking the motor itself may have a problem?

 

[flyboy2610]

One thing I noticed is that the universal joint on the motor side could be easily rotated manually which doesn’t make sense because I would think the motor should put up a lot of resistance. So now I’m thinking the motor itself may have a problem?

OK, now we're getting somewhere! I think what has happened is that the universal joint on the motor side has come loose on the shaft. That would explain why the driveshaft fell off, as well as why the locomotive won't move. You will need to remove the circuit board and reattach the universal joint. CA glue would probably work. Is this locomotive new or have you had it for a while? If it's new you may want to send it in for repairs under warranty.
Edit: I just noticed you said the u-joint fell off the worm gear. You'll need to reattach it to the worm gear. Are you certain the u-joint on the motor shaft is spinning and the motor staying still? Mark the motor shaft and see if it turns. Use a Sharpie or felt tip marker.

 

[BuzzRickson]

OK, now we're getting somewhere! I think what has happened is that the universal joint on the motor side has come loose on the shaft. That would explain why the driveshaft fell off, as well as why the locomotive won't move. You will need to remove the circuit board and reattach the universal joint. CA glue would probably work. Is this locomotive new or have you had it for a while? If it's new you may want to send it in for repairs under warranty.
Edit: I just noticed you said the u-joint fell off the worm gear. You'll need to reattach it to the worm gear. Are you certain the u-joint on the motor shaft is spinning and the motor staying still? Mark the motor shaft and see if it turns. Use a Sharpie or felt tip marker.

Thanks for your help. Turns out, the first time I tried re-inserting the drive shaft, the motor side of the shaft was seated correctly but not on the worm-gear/tower side. I went back in and made sure it was seated properly, now I’m back in business and the loco runs fine. I’d take a picture but I’ve already reassembled everything lol. Not really sure how it came out in the first place. Also, I noticed the rear one looks very securely locked in but after putting the front one back in place theres still a few millimeters of clearance between the end of the drive train and the bracket that it sits in (U-joint? I may be mixing terms up here) on the motor side. At least now if the problem reoccurs I can fix it.

 

[flyboy2610]

You need a little bit of play in the system to avoid binding up. I'm glad you got it running, and glad I could help! If you have any further issues just post them, and we'll help you!

 

[KB02]

I have a Bachmann Loco That has a similar problem. I've stopped short of having to glue it back in place. Glad you got it running again. For what it's worth, you're not alone.