Maintenance: Types and Costs

Lesson objectives:

• Classify maintenance types using the resources provided, (i.e., you don't have to memorize)
• Demonstrate relationship of various factors to maintenance costs
• Identify impact of maintenance on transit system success

Maintenance Goal and Variables

Goal: keep the maximum number of vehicles in service at all times, balancing the costs to do so.

Key variable: Whether the maintenance is scheduled or unscheduled.

Key cost variable: Maintenance salaries

Key operating variable: Operating spares ratio (OSR)

Based upon historical experience, the agency must plan for some number of vehicles to be out of service at any time, both for scheduled and unscheduled maintenance. Once these spares have been added to the peak vehicle requirement, the operating Spare ratio can be determined. For instance, these are WMATA figures for buses:

Peak Vehicle Requirement:	1,161
Vehicles for Scheduled Maintenance:	139
Vehicles for Unscheduled Maintenance:	36
Total Vehicle Requirement:	1,336
Operating Spare ratio:	175/1161= 15.1%

WMATA says 90% of breakdowns inconvenience passengers. Imagine how much greater the inconvenience would be without spare buses!