Today's track maintenance operations require anywhere from one to 30-plus machines, and they are required to perform the work in a track possession of anywhere from one to perhaps 12 hours. Each machine has a production capacity set by the manufacturer's design, the condition of the machine, the density of work required, the skill of the operator and even which side of the bed the operator got out of that morning. In addition, for some operations, several gangs, each with different production rates, may be working on the same section of track.

In short, it is a planner's nightmare. So the question is, how do you coordinate machines and gangs at a given location to maximize production in a given track possession? It's not easy.

The first question is what work is required. All the tasks must be clearly identified, not only by overall task, such as tie replacement, but by the number of ties to be replaced, the number and size of grade crossings and the number of switches in the track section. The list and variation of tasks is almost endless.