To kind of jump on what Scott said, you are going to have some problems with these units. First of all, these are complicated, with the electronics on board, and that introduces an element of risk right there, these simply are a lot more complicated that post war engines, for example.
Secondly, these are relatively low run items. In some ways, it is a lot easier to produce items that work out of the box with large runs, because they produce so many, A)they are more willing to keep marginal equipment out of the retail flow and B)if they are using any kind of statistical quality control, given how many they produce, it is likely that they quickly will find the common production issues (bad parts, bad design, bad assembly steps) and fix them. The other issue with large runs is they aren't as concerned about high margins to make profits, you can make as much profit selling 1000 of an item at a buck margin, as 1 with 1000......
With the toy train manufacturers, it is a different story:
1)Small runs relatively, with complicated parts, doesn't even really allow much basis for statistical quality control.
2)With the need for large margins, they aren't going to spend a lot of time on quality improvement at the source, so you won't see lean production techniques and such, that lend themselves to quality, their model is based on using cheap assembly resources, with a relatively unskilled workforce. The biggest factor in quality and productivity is capital,i.e investing money and time in producing things from the get go with quality in it.
3)Inspection quite honestly only improves quality for items that are really DOA, where it is evident, it does poorly with marginal items. So if an engine comes off the ship, and whoever is their QC inspector runs it at the factor, running some basic checkout, it could work great, by the time it has sat in a wearhouse, gotten shipped to you or an LHS, and taken out of the box, that marginally connected wire, that chip who was marginal to start with, the circuit board with the tendency to crack, might fail.
For cheaper items, they might inspect at the factory, where if they put it on the track and it seems to run, it passes, they won't notice the rear light is out, the grabiron is bent, the paint is scratched, because quite frankly, their job is to see if the thing runs briefly, period, and they aren't exactly going to be hobbyists themselves.....
4)With limited markets like toy trains, the competition quite frankly is limited, and when all of them are using the same model, not surprising we may not always be happy with the quality (and again, I am not saying that the quality on these units is bad, good or indifferent, my experience has been good, but I don't run command and have relatively few new units).
What usually drives quality improvement is what is known as cost of quality (really, cost of low quality), which basically is how much does it cost us when a unit is defective? That cost is the cost to repair the item, plus the opportunity costs if the lack of quality causes them lost sales. If those losses still allow them to make money, if the cost of quality is less than the cost of addressing the issues, they don't do it. The US auto industry for years operated on a model where they didn't care about the cost of quality, they were making so much money, that the cost of quality in dealer repair work and such, and dissatisfied customers, didn't matter (in large part, like the toy train companies, they all used the same model and had the same issues, so jumping from Ford to Chrysler didn't help). It was only when foreign cars, with lean production techniques and true quality control, i.e a valid alternative, came into the picture that the big 3 was forced to change.
With toy trains, it is annoying, but quite frankly, it is something we will have to live with, until their is economic motivation in doing so, quality assurance/quality control is going to remain an issue at some level. It can be improved, few would say that PS2 or PS3, for example, is less reliable than PS1, changes in design will often get rid of old issues, I am just saying that there isn't the impetus for the kind of quality we have come to expect with other products, this is more like craft made stuff in some ways than modern mass production.
