If you want something done right, hire a nerd.
I know that's not the way the saying really goes, but let's face it, for most things, you couldn't do them yourself anyway. If you want your computer fixed properly, you should almost certainly not do it yourself. If you want someone to tell you exactly how much equity you have in your home based on current appraisal value and time value of money, you should probably not try to figure that out on the calculator that came with your cell phone.
And if you want to set up a toy train display that will bring in crowds and impress everyone, you should not leave that to the local craft club that meets at the rotary club on Tuesday nights after the crochet class leaves. Unfortunately, if you go see the trains at the mall, that's what you're likely to see.
Christmas, that most despised and odious time of year, brings out many horrible things, like rude shoppers, crappy parking, and repeated airings of 'Feliz Navidad.' But it does have a great benefit - people break out model train dioramas left and right. These run the gamut from 'holy crap, that crane is actually unloading the cars!' to 'why is that guy's head bigger than the front window of the store next to him?' And of course, Christmas brings out the uninspired, unoriginal, profiteering bastards who put less time into actually creating the spectacle than they put into marketing it for ten-year-olds and hiring moody teenagers to sell tickets.
The mall shows that get all the publicity are frequently publicized by local news stations, who are giddy to tell people about the pathetic train shows because the marketing people are giving a sliver of the money to some nationally known charity that buys hats for bald kids while they're on chemo. If you're trying to decide if the train show is worthwhile, avoid any affiliation with Marines at Ronald MacDonald's Toy Box Christmas Tree. If you see those big-name charities, it's a sure bet the trains will suck.
If you are interested in seeing some great train displays (and I am - I once saw a scale model of the French Quarter that filled a large display hall, and I spent two hours looking in the windows and checking out the inch-tall street walkers), then you need to find nerds. Look for local model train clubs. Especially around this time of the year, these enthusiasts shake off their mantle of secrecy and open their doors to allow the unwashed masses to walk slowly past their thousands of hours of hard work, allowing their preschool children to lean on the plastic retaining walls and pull parts off the scenery. This, of course, causes incredible consternation among the train modelers, but if you're naive enough to think that you can invite seven hundred people to look at your painstaking effort and carefully constructed dioramas and none of them would be rude enough to just break your crap, then you're high. Any place you put more than ten people, someone is a douche bag.
Still and all, if you want to see some examples of careful, cautious, devoted model-train nerdery, you simply cannot beat an enthusiast's club for dedication and attention to detail. Avoid the mall trains entirely - they seem to think that they've built a whole scene if they have a ceramic old man with his dog next to a model car that would bruise his kneecaps if it hit him in a high-speed chase, and put them both next to a caboose built completely from cheap Chinese plastic, decorated with the names of whichever loser family decided to give ten bucks to Angels of Christmas so that every loser stupid enough to get duped into a six-dollar ticket could see that they were an upright and holy family. The mall train sets have no sense of scale. They lack the obsession over detail that marks the true nerd, and thus are less than merely adequate.
On the other hand, if you can handle having very uptight hobbyists staring down their noses at you and slapping the hands of every street urchin who wants to drop his gum into the tiny model creek, you should treat yourself to a real train show. And now is the perfect time of year to do it - especially if you can go while everyone else is at the mall.