Onaga ? Union Pacific says it’s found the cause of one of two coal train derailments in northeast Kansas in recent days.

Twenty-three cars of a 133-car train bound from Wyoming to southeast Missouri derailed Thursday near Onaga, in Pottawatomie County.

Union Pacific spokesman Mark Davis told The Topeka Capital-Journal on Monday the derailment was caused by a broken axle near a wheel bearing on one of the cars.

On Saturday night, 43 cars of a 134-car Union Pacific coal train went off the tracks near the town of Silver Lake in Shawnee County. Some of the coal spilled into Soldier Lake.

The cause of that derailment is being determined. The train was traveling the same route — Wyoming to southeast Missouri — as the one involved in the July 8 incident.