Back in the early 70’s, I was working for the contractor charged with installing track on the first 4.6 miles of the Washington, DC Metro. For the underground and aerial sections, the installation required a grout pad to support the elastomer-coated rail fastener pads. Our company ordered a custom Gomaco machine to lay a continuous grout pad, after which we could drill holes and install anchor bolts to hold down the pads. This worked well on the aerial structures, but not so well in the tunnels.
The concrete inverts placed by the tunneling contractors varied from the specification tolerances and was often too low or too high for the Gomaco to perform properly. Subsequently, we ended up having to locate, form and pour individual track pads throughout a significant portion of the tunnels, greatly increasing our costs. We conducted our own survey of the tunnel every 50 feet to demonstrate the out-of-tolerance inverts, and carefully tracked costs by location. At the time, we were already utilizing a computerized job cost accounting system, so tracking actual costs was not difficult. We benchmarked our typical cost to perform a 100-foot section of aerial track, including the Gomaco and anchor-bolt installation. Although it didn’t have the name at the time, this in effect was our measured mile. We successfully negotiated all costs above and beyond the benchmark for the out-of-tolerance sections.
The measured mile has become an accepted method of proving and quantifying inefficiency cost. In the example above, the identification, causation and quantification were clear-cut, but in many situations, it is not. Sometimes there is no clear-cut section to establish a benchmark, or to separate the increased actual costs. In an excellent paper on the subject, William Ibbs and Josh Chittick provide a review and synthesis of project management literature and court and appeal board decisions to present practical considerations in the identification and application of measured miles. The intent is to help contractors, owners, consultants and other parties step through a logical process for preparing and presenting a credible measured mile analysis. The paper is available free to ConstructionPro Network members but is available for purchase in our bookstore for non-members. Click here for the report.