A cracked rail delayed some Metro rail riders on Thursday morning, the latest in a string of problems with tracks breaking.

The crack was found around 8 a.m. near the Stadium-Armory station on the Blue Line by the automatic train safety system, said Metro spokesman Dan Stessel. He said normal service resumed by 10 a.m., after causing 10-minute delays for Blue Line riders heading west.

It was the latest cracked rail on the system. On Feb. 29, another crack was found on the Green Line near Southern Avenue. That was at least the eighth found so far in 2012.

In January, the agency had six cracked rails. The numbers of cracks have been increasing in recent years, as The Washington Examiner first reported in February.