Purpose - The purpose of this study is to identify maintenance related losses, and their causes, in order to describe different deviations in the maintenance process that contributes to incidents and accidents at the Swedish Railway. Design/methodology/approach - In this paper incident and accident reports from 666 derailments and collisions at the Swedish Railway during 1988-2000, stored in a national database, are studied with respect to possible maintenance related causes. Findings - The railway is a complex technical system used for both freight and passenger transportation. Maintenance is one way to achieve safety and dependability of the railway. However, at the same time badly performed maintenance may also cause accidents. The study shows that maintenance related causes represent 30 percent of all rail and track related incidents and accidents represented in the database. About 80 percent of the maintenance related accidents happen during the execution phase. The most common cause of maintenance related accidents is imperfect communication and information between the maintenance personnel and the operators. Rule violations, especially lack of permission to perform maintenance work on the track, are the second most frequent causes. Originality/value - Identifies maintenance related losses, and their causes, on Swedish railways but is of value to all concerned with transport maintenance and safety.