D
Derail
A track structure for derailing rolling stock in case of an emergency.
Detail Fracture
A progressive fracture originating at or near the surface of the railhead. These fractures should not be confused with transverse fissures, compound fissures or other defects which have internal origins. Detail fractures usually have their origins in the following types of defects, and progress crosswise into the head of the rail:
1) Shell - Where a thin shell of metal becomes separated from the head, usually at the gage corner.
2) Head Checks - Usually at or close to the gage corner where movement or flow of surface metal is sufficient to start a hairline crack.
A track structure for derailing rolling stock in case of an emergency.
Detail Fracture
A progressive fracture originating at or near the surface of the railhead. These fractures should not be confused with transverse fissures, compound fissures or other defects which have internal origins. Detail fractures usually have their origins in the following types of defects, and progress crosswise into the head of the rail:
1) Shell - Where a thin shell of metal becomes separated from the head, usually at the gage corner.
2) Head Checks - Usually at or close to the gage corner where movement or flow of surface metal is sufficient to start a hairline crack.
