While Mike Cawdrey has managed to accomplish the impression of poorly maintained trackage to perfection, I don't think that many others would be so successful in their attempts to mimic it. I'm sure that reliable operation under such adverse circumstances calls for not only being rather selective in the choice of motivepower (limiting engines to only 4-wheel trucks) and rolling stock, but also over-weighting both locomotives and cars to maintain solid contact with the rails. Allowing enough play for trucks to pivot in both axis can also result in an unrealistic shaking of the cars when operated at mainline speeds elsewhere on a layout.
Even on the prototype, such poor trackage drastically limits operating speed and often results in putting cars on the ground. While having such trackage may be a novelty at first for the modeler, I think that in the long run it is more likely to become too unsatisfactory and troublesome to leave in place.
NYW&B