One wheel of a Metro subway train carrying a work crew derailed early yesterday as the train went through a switch, Metro officials said. There were no injuries.

In an unrelated development, two Takoma Park men were arrested and charged with placing obstructions on railroad tracks after a Metro train ran over planks near the Takoma station.

The derailment occured at an X-type crossing switch between the Penetro officials said they were still investigating the reason for the derailment. The switches were locked into normal operating possition in preparation for the morning rush hour.

The Takoma incident occured about 5:40 a.m. A train carrying a crew to work at Metro stations along the Red Line hit the planks at the point where the tracks cross Piney Branch Road. The planks splintered, but there were no injuries.

Metro official and police were called. The first to arrive was Cody Pfanstiehl, Metro's public affairs director. Pfanstiehl and Takoma Park policeman Craig Murphy found a 49 pound concrete block and a bent steel reinforcing rod placed across the Chessie System railroad track that parallels the Metro line. They removed the debris.

Murphy then spotted two men in the area and arrested them. D.C. police were called because the arrest took place just a few feet inside the D.C.line. Then men were questioned, then charged.

Police indenrified the men as Warren W. Wilson, 21, and Alan L. Daugherty, 18, both of Takoma Park. Arraignment is scheduled today.