Business Process Design for Optimizing Car Fleet Availability

We designed and developed a Vehicle Out of Service for Parts (VOSP) system for redeployment of used parts on subway cars, with the ultimate goal of returning more cars to service earlier than otherwise possible.  At that time, the subway was suffering from a decade of neglect and disinvestment, where there was a non-homogeneous fleet and many cars had outstanding defects that have not been repaired due to a lack of immediate resources.  Investment dollars were scarce and major parts were difficult to come by, requiring multiple level of approvals, and even when approved a manufacturer may or may not be found due to some having gone out of business in the interim.  The net result was that many cars were “stopped” on shed, each requiring a different major component, and special attention by skilled fitters.  To maximize the utilization of assets, working with mechanical engineers at the overhaul shop, we developed a concept of component replacement where labor dollars would be invested in swapping a functional major component between two “stopped” cars to make one functioning vehicle.  Whilst this ultimately does not reduce the shop workload, it does allow more vehicles to be available for service, which was an important performance measure.  We developed a process by which each defective car entering the barn would be subject to a diagnostic examination to determine the components likely to have failed (in some cases this was obvious, such as a traction motor flashover; in some cases it was less obvious as the failure symptom may indicate an underlying issue that should be addressed prior to renewing a failed component).  A database was kept of all cars on shed and a mechanical engineer would review the defective car inventory and authorize major components to be swapped between cars when appropriate, taking care to ensure that any underlying defects are identified as not to risk destroying more serviceable components.  This system also enabled the depot personnel to better plan for the shop’s backlog workloads in each major systems, e.g. if many brake components were awaiting specialist attention, those specialists would be asked to put in overtime to reduce the backlog.  Overall this was a substantial contribution to the productivity of the shop and the consist compliance performance on the road, and formed the basis of the preventative maintenance system that was deployed by the car maintenance dept. many years later.