Broken base - Rail defects

Broken base - Rail defects

Figure 1: Broken base.

Defect name: Broken base
Record No.: 2578
Type of defect (Internal/Surface): Internal, surface
Defect classification: Rail defects
Steel name: Steel
Steel composition in weight %: No data.
Note: A base defect is any break originating in the base of the rail. It should be noted that any defects in the base area cannot be currently detected by rail testing software. The most common base defects are: Broken base and base fractures Sizing for base defects is normally reported in inches.

Definition - A broken base is a progressive fracture in the base of the rail, with a vertical separation or split. A broken base is normally confi ned within the fl ange area of the rail base and is usually an ovalshaped break called a half-moon break.

Origin - Separation may be caused by improper bearing on ties or tie plates, or may originate in a seam, segregation, or inclusion.

Growth - Growth usually depends on the location of the break and the loading of the rail.

Appearance - Broken base defects appear as one the following:
• A crack starting near the junction of the base and web, extending outward to the edge of the base.
• A longitudinal crack extending along the junction of the web and base.
• A half-moon break in the base of the rail.

Hazard - A broken base is dangerous because:
• The remainder of the rail cross section becomes weakened.
• Upon service failure, the rail may break into several pieces.
Reference: Not shown in this demonstration version.