Correct Answer - Option 3 : +0.8 mm to -0.4 mm
Concept:
The rail specifications (IRS-T-12-96) for flat-bottom symmetrical rails, the tolerances allowed in the various parameters of a rail section are given below:
Parameter
|
Permissible Variation
|
Overall height
|
+0.8 mm to -0.4 mm
|
Width of head
|
± 0.5 mm
|
Width of Flange
|
± 1 mm ( If section < 60 Kg/m
+ 1.2 mm and -1 mm ( If Sections ≥ 60 Kg/m)
|
Thickness of Web
|
+ 1 mm to -0.5 mm
|
Vertical Flange
|
± 1.2 mm
|
Length of Rails
|
+2 mm to -10 mm
|