According to JR Freight, staffs of Goryokaku station discovered sparks came off from an axle of freight train(20 units) at Hakodate freight terminal in Minato, Hakodate, Hokkaido at 6 o'clock on April 26th.
The train ran with its wheel derailed ,and the wheel probably returned to normal.
No staff on the train was injured. The train departed from Hiroshima Freight terminal at a quarter past 9 o'clock ,and headed for Sapporo Freight terminal.
According to JR Freight, every train stops between Kamiiso and Nakaoguni on Esashi Line. JR East decided to suspend Limited Express"Hokutosei" and "Twilight Express" from Sapporo to Osaka.
Citation: http://www.asahi.com/travel/rail/news/TKY201204260292.html
Since May,2011, JR Hokkaido caused fatal accidents of 3 times. Though I don't know whether each cause is related mutually or not, JR Hokkaido will have to pay attention to safety.
