For the first half of 2017, Metro reported a 9 percent drop in customer injuries. (Jabin Botsford/The Washington Post)

Metro’s efforts to crack down on track fires appear to have yielded some progress — even if arcing-insulator headaches continue to plague Metro riders.

In Metro’s latest safety report, which summarizes the system’s safety performance from January to June, the agency logged 50 fires on the tracks, a 39 percent reduction compared with the same six-month period last year.

Much of that improvement came from efforts to reduce the number of non-electrical fires, which occur when trash, leaves or other debris become overheated on the tracks and begin to smoke or smolder. Those incidents were down by 56 percent in the first six months of the year.

Arcing incidents, caused by stray electrical currents, also appear to be on the decline: Metro logged 34 of those incidents in the first half of 2017, which is 13 fewer than the year before.

Still, arcing incidents persist, and they continue to affect on-time performance and riders’ perceptions of the system. On Monday morning, hours before the safety report was released by Metro, a pair of arcing incidents reported on the Red Line halted train traffic between the Medical Center and Friendship Heights stations, sending ripple effects through the rest of the line.

The customer injury rate in early 2017 was down 9 percent from last year, with 308 reported injuries — two injuries per million passenger trips. That falls short of Metro’s goal of 1.75 injuries per million trips.

Many of those injuries were caused by passengers tripping, slipping or falling. In the report, Metro officials outlined some of the problems they believe put passengers at risk. Hard braking on buses causes customers to lose their balance. And loose floor tiles and poor station cleaning can lead to uneven or slippery surfaces where passengers walk.

Recently, Metro installed audio warnings on station escalators particularly plagued by passenger injuries to alert riders that they are reaching the end of the escalators and should hold onto the hand railing.

“WMATA is monitoring the effectiveness of the piloted automated precaution announcements which were installed at the escalators experiencing the most injuries,” Metro said in the report.

On the rails, there were five red signal overruns in the first half of 2017, down from six the year before, according to Metro. Operational rail collisions stayed about the same, with 10 incidents logged last year, and nine logged this year, the report said. Six of those nine incidents involved “road maintenance machines,” rather than trains providing passenger service.

“Operational collisions include minor bump post contact, hard couplings, and unsecured components of RMMs (e.g., arms) striking shop equipment and walls,” Metro said.