Reducing Earthquake Risk on the East Japan Railway through Investment in Safety

Earthquakes can cause catastrophic accidents to the railroads in terms of serious facility damages and large number of passenger fatalities and injuries. To reduce earthquake risk, various safety counter-measures can be employed. Among them, performing an accelerated construction program of track strengthening, retrofitting rail viaducts, installing warning systems, and improving the braking systems are considered by JR East. This thesis first modeled and estimated the collective earthquake risk which includes the physical damages due to track or viaduct failures and passenger fatalities and injuries due to the train derailment when running trains hit the track failures. Both the base collective risk and the perceived collective risk are calculated by employing the concepts of Safety Performance Index (SPI) and Perceived Safety Performance Index (PSPI). After assessing the earthquake risk, benefit-cost analyses are carried out for each of the four safety counter-measures. The design of the most cost efficient plans for both single and multiple track strengthening projects are studied here. Based on the benefit-cost analyses, the thesis uses a case study to develop a safety management plan in terms of allocating the investment among the counter-measures to reduce the earthquake risk. In the case study, the optimal investment allocation plans are obtained under different budget restrictions. When the risk level decreases, the marginal investment for reducing one additional unit of risk increases no matter which safety counter-measures are used as the optimal. In addition, if different risk measures in terms of different conversion factors to calculate the PSPI are used, the optimal investment plan may be different. Thesis Supervisor: Joseph M. Sussman Title: JR East Professor, Civil and Environmental Engineering