Railroad execution and planning need to be dealing with the same range of significant digits.
For those of us who began our engineering studies before the 70’s, the practicality of the slide rule is well appreciated. This intriguing device of sliding scales, that miraculously performs multiplication and division via the addition and subtraction of non-proportional linear distances, minimized the terror of dealing with an endless flow of variables encompassed in complex engineering equations. That was the heyday for analog mathematical devices as digital computers were being somewhat reluctantly infused into the engineering ranks, and accordingly, it was the pinnacle for the art of approximation, the art of defining squishy limits. Using the slide rule required thinking in terms of powers of 10 as well as understanding that there was a clear rationale to acceptable precision, what was referred to as “significant digits”. For example, did the resulting answer of 8.something shown on the slide rule’s “D” scale after multiplying and dividing a series of 27 numbers actually mean 8.2 ? or 8.25 ? or perhaps was it .0082 ? or maybe 8200 something? Back then, “being close” was good enough, in fact expected, as test scores were partially determined by the proper use of the slide rule.
With the introduction of the personal calculator, arrived the immediate requirement for precision. This was not a level of precision, however, that one had to work for, but instead it was that which was instantly provided to the user on green-lighted displays. If one required the square root, or even a discounted cash flow, one needed only to push the appropriate function key once the data had been entered. And, there was no limit to the number of digits of preciseness it seems. The mind was given the answer, without thought, without question and, unfortunately, without the opportunity to truly understand the underlying mathematics.
Interestingly, for major railroads in North America and across the globe that are either primarily non-scheduled or without moving block operations, the planning and execution processes for traffic management employ opposite extremes of understanding the underlying mathematics and the discipline of approximation. Practically speaking, there is a very real opportunity for railroads to transition train dispatching from an art to a science by including mathematics-based movement planners. Currently, the approximations inherent to moving trains are so broad that the railroads are running below capacity in critical corridors. These inefficiencies are due to the lack of both timely train position and speed and the tools to handle the continuous mathematical processes, specifically reactive and proactive planners. The former would assist the dispatchers with the current approach of crisis-based traffic management, whereas the latter would provide for the prediction of traffic conflicts and subsequently the ability to avoid them.
Whereas the execution side skimps on the mathematical processes, thereby resulting in broad approximations, the planning side of operations embraces the other extreme. Supported by incredibly complex mathematical algorithms being endlessly massaged on digital wizards capable of truly mind-boggling computations per second, the railroad planners pursue the absolute opposite of approximation with the concept of significant digits being totally unknown in their profession. To them, precision is a truly achievable dimension that is to be expected and respected. As such, the Planners proudly serve up their precise results to the execution side, only for many of those results to be dismissed either directly or during execution as reality sets in. This rejection is the inevitable result of either the inability or unwillingness of Operations to handle the significant problems and changes that come with execution and that inevitably make the Planners “precise” schedule an impossible reality. Operations, of course, accepts this lot in life and their thus “un-planned” execution as…inevitable, since they rationalize the events that befall the schedules to be beyond their control. However though, most are actually within their control.
The execution side has a long way to go in tightening their processes. They need the data and tools that will permit them to approach the level of performance that the planners are attempting to achieve. Conversely, the planners need to back off. They need to incorporate squishy limits into their planning processes. I have seen some asset planning tools that have managed to do that, but I assume most still do not . In a rather simplistic way, one could say that execution and planning need to be dealing with the same range of significant digits.
They clearly aren’t today.