Can it run better?

[JRP]

Hello. I have the Santa Fe 4-8-4 Northern....the second 4-8-4 locomotive that Bachmann shipped me just last year after the first one (purchased Feb 2008) had a series of operating issues including staying on the track. This 2nd unit runs slightly better, but only after I changed the decoder to a Tsunami Heavy Steam and also clipped the capacitor across the motor circuit that effects the speed curve when using a quiet drive decoder (this last move was highly recommended from several other 4-8-4 owners on this Forum). Bachmann also admits it's "newer" 4-8-4 units run better. But I still can't get the locomotive to run "smoothly" at slow speeds. The drive wheels tend to "jerk" slightly when it is slowly moving or moving downhill and on clean track. I have read other folks messages saying with the same thing. QUESTION: is there a way to correct this or at least reduce the jerky movement? Would I have to take the entire motor assembly apart, or replace the motor? (I hope not). Any suggestions you have are welcome. I just would hate to send this back again. The steam sound, however, is wonderful with that Tsunami. Thanks. JRP

[Boise Nampa & Owyhee]

Jerking or hesitating could be quartering of some piece of linkage binding on the way around.

Place it on the track and watch the side rod location for where the bind occurs....... when it gets to that location rock the loco off of the track to stop it immediately.  Then turn the loco over and wiggle side rods and valve gear for something that is not flopping around.  All that monkey motion has to be absolutely friction free or the loco will show it up.

I've never been a fan of Bachmann so I'll quit there.

see ya

Bob

[JRP]

I don't remember if I ever ran it on DC, but it sounds like a good idea just to see if I have the same results.

[locoi1sa]

Is this one of the Bachmann locos with the cogged drive belt? I have a couple and if they sit for any period of time the belt gets a set and makes the loco jerky at slow speeds. If that is not the issue check for quarter of the drivers. The best way to diagnose the problem is to remove one side of the drive rods and try it. If it is smoother then you have a quarter issue.

  My observation of Bachmann products is that they either run good or not very well at all.

         Pete

[ATLANTIC CENTRAL]

John,

I'm going to assume this is one of the newer ones with tender wires/pickup and the improved drive.

Having considerable experiance with Bachmann locos, but little with this specific loco, I will make the following suggestions.

Check for binding as others have mentioned.

Add weight to the tender to insure better electrical pickup. Check the positioning of the engine to tender wiring, make sure it is not binding - it can lift the engine or tender and effect running and electrical pickup.

Check all lubrication issues, sometimes there is too much, sometimes too little, sometimes its dried up.

Reference another post about belt drive, your loco is not belt drive.

Do you have a continious loop of track? Put it on the track, run it at 2/3 throttle for a few hours, reverse the drirection, run it a few more - break it in. Maybe more so than any of the current brands, Bachmann locos seem to benifit from some "run in" time.

I have a large roster of Bachmann steam locos, but the Northern in question does not fit my modeling theme. While many people do not care for Bachmann, I find that most of their offerings are a very good value, and if they don't run perfect out of the box, issues are usually simple and easy to fix.

The drive in the new Northern is very similar to the drive in their 2-8-4. I have five of those which I have converted into heavy 2-8-2's and added considerable weight to, improving their pulling ability. They run very nice.

Sheldon

 

 

[wjstix]

I'd check the siderods too. I had a Bachmann / Spectrum engine that hesitated every rotation of the wheels. It turned out that somewhere between China and my mailbox, the siderods had been pushed in slightly so they were binding at a certain point every rotation. Bending the siderods out slightly solved the problem and ever since it's been one of my best running engines.

[JRP]

Great advice Sheldon. I will do just as the doctor ordered. I had not thought of any of this before. I do know I have not run this loco all that much, and now will attempt to break it in, along with the other suggestions. Will keep you and the forum updated on the progress as that is always helpful to other readers who may have the same issues. JRP

[JRP]

Thanks WJSTIX. Will check this out as well. I hope I can get this 4-8-4 to be one of my best running engines too. JRP