In June, Chicago Metra’s on-time performance rate was 95.8% — up from 93.1% in June 2014. This improved performance follows three months in which Metra’s on-time performance met or exceeded 97%: 97% in March and 97.2% in April and May. For the first half of 2015, the systemwide on-time performance rate was 95.8%.

“A critical part of Metra’s on-time reports is a comprehensive analysis of what causes train delays,” said Metra Executive Director/CEO Don Orseno. “Our goal is to identify delays that could have been prevented so that we can continue to improve our performance.”

As part of its continuing efforts to increase transparency and accountability at the agency, Chicago’s Metra announced the top 14 causes for train delays in June 2015. The list breaks down whether the causes were the primary or a secondary reason for the delays and then ranks the causes by the total number of delayed trains per month. In June, 735 of 17,433 trains were tardy by six minutes or more.

The most common cause for delays in June was mechanical problems, either due to a mechanical problem on the train itself or a delay caused by a mechanical problem on a train or trains ahead. Although some mechanical delays can be prevented, the age of Metra’s rail cars makes it increasingly difficult and time-consuming to keep engines and cars operating smoothly.

The second-most common cause for delays in June was train loading, which occurs when trains remain at a station longer than expected. Factors that impact loading include the need to load high a volume of luggage, strollers or bicycles, and delayed boarding due to poor weather conditions.

The third-most common cause for delays was freight train interference. In some cases, Metra and its partners have operational control over freight traffic. However, on many lines and at many crossings, Metra has no control and must coordinate closely with freight operators to keep all trains on schedule.

Signal or switch failures, right-of-way accidents, weather and track construction were other major causes of Metra train delays in June.