Unfortunately your words did not provide too much encouragement.  I sense the beginning of a trend here but, I don't want to jump to conclusions.  I have to give Bachmann a fair chance considering I have not even sent the loco in for servicing yet.

I did realize one other thing: I was inspecting the loco's tender and noticed that the wheels all appear to be insulated on one side (I do have to turn one set of wheels around to match the others in one of the trucks).  It seems possible to use them as electrical contacts and run a discrete wire or two from the tender to the loco's motor.  Maybe that will provide better and constant contact with the rails, and provide smoother motion.

Of course, care will have to be taken to make sure the wiring from the tender's wheels matches the flow that the loco should be getting from the rails, in order to avoid a short circuit.  Also, there is the question of whether I can find wire thin enough and flexible enough so it does not force either the loco or the tender to derail.

However, this does nothing to address the issue of the loco's wobble.

I may attempt this if Bachmann's remedy is unsatisfactory.

I recently purchased the Empire Builder set to run around our Christmas tree.  Eventually I plan on building a small scene to run it in.  Being entirely new to n-scale (and never having built a model railroad further than having an oval of track tacked to plywood in HO scale a few decades ago), I unfortunately am having a few issues with the loco that comes with the set.  It is a 4-8-4 Northern, and It has a very choppy, jerky motion, in addition to a bit of a wobble.  Obviously the jerkiness is due to the loco not making good contact with the rails.  Although the set is less than a week old, I did take the initial measure of using alchohol to clean the rails and loco's wheels in an attempt to improve the contact, to no avail.

In further examining the loco, I noticed that the little sliver of copper serving as an electrical contact between the loco's body and the pilot truck was providing too much spring, resulting in the front two sets of drivers (both left and right side) hovering slightly above the rails.  I removed the pilot truck and relaxed the springiness and reassembled it.  It seemed to help somewhat.  Now, instead of running smoother in reverse (note: smoother, not smooth), it runs smoother going forward at the expense of being more jerky going in reverse.

After further examination, it still seems that the first two drive wheels are hovering almost imperceptably above the rails, though now only on the right side.  I can't relax the springiness of the contact under the pilot truck any more than it is.  At this point, I don't know if it is even making contact and providing any current, although it does run better.  It seems that the loco may only be getting current from the rear drivers (the third set of drivers has the traction tires).  But even at that, I am not so sure the rear most driver on the left side is making good contact with the rails.  In addition, it is still unclear to me if the trailing wheels provide a pathway for current, though I do see plastic insulators inside the wheels on the right side (as opposed to plastic insulators on the left side of the pilot truck).

This intermittent performance can result in the loco crapping out at lower speeds, sometimes only for a second; sometimes I have to tap the loco, or the track near the loco to get it to resume.  It will not even budge if I set the power-pack dial to anything less that 30% power.  As a result, I can not get the loco's wheels to turn slow enough to determine what the origin of the wobbling is.

I do understand that there is a difference between toy trains and model railroading.  And I am also aware of what Bachmann's reputation was as little as a decade ago, and that they have done a great deal recently to clean that reputation up.  They should be rightly proud of bringing the company from what they were to what they now are, and believe me, it is not my intention to bash the Bachmann product line.  In all honesty though, I believe it is fair to say that this particular set is not exactly the top of the line.  I wanted to start out with a relatively inexpensive set, and maybe build a small winter scene to put under the Christmas tree to run it in for my 3 year-old daughter's (and my) enjoyment.  (I don't want to go to expensive, because I figure she will probably go Godzilla on it).

I have read on these forums that many users have been impressed with how their Bachmann's have outperformed their Kato's, creeping tie by tie at a scale 5 mph.  Am I mistaken to expect this sort of performance from this loco?

The obvious course of action is to send the loco to Bachmann for repair/replacement under their Lifetime Limited Warranty, which I will be doing shortly after the holidays.  Of course, there is also the possibility that someone can suggest a simple quick fix, though I wouldn't want to tamper with it too much for fear that Bachmann's service department may declare that it has been altered to much to consider it still under warranty.

The only two remaining options I can see are returning the set (which I'd hate to do because I am actually very pleased with it otherwise) or sell the loco on ebay and buy a similar one from a different manufacturer (for as much as I paid for this entire set).

I am just wondering what other people's experiences have been regarding this, or similar models.  Are my expectations too high?  Can it be something other than the loco itself?

Aside from that, assuming that I do get satisfaction from Bachmann on the above issues, I was wondering if anyone can tell me if this 4-8-4 Northern would have any problems running on code 55 track, or does it have "pizza cutters" as I have heard them referred to on the forums?