An Approach to Calculate Overall Efficiency of Rolling Stock for an Urban Rail Transit System

Inefficiency of urban rail transit systems (URTS) results in a lower standard of service than required and has negative economic impacts. Many efforts have been undertaken to calculate the efficiency of URTS or their subunits. Overall equipment efficiency (OEE) as a measure of efficiency is a simple, flexible, and efficient formula. The OEE measure ensures that equipment is available and fully capable of producing quality goods/services for the maximum time of operation and is being used in a proper way. This paper discusses the idea of the OEE from the field of production and how it can be applied to a URTS. Overall efficiency of rolling stock (RS) is a major influencing factor on the efficiency of URTS. Therefore, the three fundamental parameters of OEE—availability, performance, and service quality—are defined for the RS of a URTS, and a method for their calculation is presented. The usefulness of OEE for URTS is investigated. Introduction Improving and maintaining the efficiency of rail transit systems has become important due to limited public funds and an increase in transport demand (Sulek Journal of Public Transportation, Vol. 15, No. 1, 2012 20 et al. 2000). There are many ways to calculate the efficiency of a public transport system or one of its subunits. For schedule and operating personnel efficiencies of a transit system, we refer to Vuchic (2005) and Edwards (1992). In terms of economics, technical efficiency is measured by the ratio of output to input (Cooper et al. 2004). Depending on the type of system, there can be single or multiple inputs/ outputs. In the case of an urban rail transit system (URTS), multiple outputs are produced by multiple inputs. Currently, several inputs/outputs of a transit system are in use to develop a performance measurement system (Sulek and Lind 2000) . Additionally, each URTS has different subunits, with each subunit having a variety of inputs/outputs. Individual lines of network, transit units of a particular type in a vehicle fleet, parking management, park-and-ride lots, and collection of fares are some examples of subunits. Any subunit of a URTS that runs with low efficiency can cause the following: • less profit for the transport company • cost increases due to extra wages for drivers and maintenance and other staff who are in charge of overcoming actual deficiencies • increase in service costs because of rework • waste of energy, materials, and work force • impacts on pricing Therefore, the focus should be on improving the overall efficiency of URTS. One way of achieving this objective is to identify and improve the efficiencies of the individual subunits (Barnum et al. 2007). Another way to improve would be to adopt strategies that result in the more efficient use of transportation resources (VTPI 2011), which is called transport demand management. It is important that different measures for strategy and input/output for efficiency must correspond to the objectives of the transit agency. However, the core objective of any transit agency is to ensure that the transit system is available, fully capable of producing quality services for the maximum time of operation, and being used properly. This leads us to use a measure that is called overall equipment efficiency (OEE) and is taken from the field of production (Borris 2006). It focuses on the core objective mentioned above. OEE as a measure for efficiency calculation is a simple, effective, and flexible formula. It measures the efficiency of equipment during its planned operation time. This paper outlines the background of OEE and describes how it can be defined for URTS. Some issues regarding its application to URTS are addressed. It is investigated whether the OEE measure is useful for calculating the overall efficiency of URTS. What kind of information and results will be obtained for the specific case