The Post's series on Metro late last spring [front page, June 5-8] showed the need for transit systems to rethink the way they maintain their fleets in order to reduce maintenance costs and improve service. The problem is using limited resources against seemingly unpredictable problems. And given Murphy's Law, things always seem to break at the worst possible time.

But what if equipment were monitored so that potential trouble were detected early? Wouldn't that help avoid an overheated bus in the middle of rush hour or a stalled train on the Green Line?

In St. Louis, a sensor system for engines and transmissions is being tested with 20 buses to see if it can improve efficiency and service and lower costs.

As The Post's series demonstrated, most fleet maintenance is done after something breaks or on an unvarying schedule, regardless of need. The sensoring system, in contrast, is reactive, so if a bus starts burning oil, it gets noticed.

In the St. Louis test, an ideal performance model was built for each bus outlining how the engine and transmission should behave. Information from the sensors is analyzed for deviations from the standard, and the transit system then can decide on maintenance.

The sensor system spots small problems before they become big ones. In one instance, the St. Louis system showed that part of a transmission was overheating. The problem was corrected before it grew into an expensive and disruptive repair.

The more a system can reduce unscheduled equipment downtime, the more it's spared the expense of extensive repairs, overtime for technicians, express charges for shipping parts and, most important, customer delays and dissatisfaction. "Predictive monitoring" also can extend the life of vehicles while reducing the overall cost of ownership and maintenance.

Emerging technology, such as predictive monitoring, can help Metro improve its performance. Avoiding the bus breakdown that leaves 30 passengers stranded for an hour and blocks a lane of traffic is a goal for the system that everyone can agree on.

-- John Maguire

is a managing partner in

the company conducting

the St. Louis bus tests.