The switch angle depends on
(i) Heel divergence
(ii) Length of tongue rail
(iii) Flange-way clearance
(iv) Throw of switch

The correct answer is

Explanation:

• Switch angle is the angle between the stock rail and the tongue (switch) rail at the point where the tongue rail starts diverging.

• It determines the divergence rate of the moving rail from the fixed stock rail in a turnout or switch.

• A smaller switch angle allows smoother transitions and is suitable for higher speeds, while a larger angle is used where space is limited.

• The switch angle plays a key role in determining the length of the turnout, comfort, and safety of train movement through diverging routes.

• It directly influences how quickly the rail diverges, thus affecting the lateral force exerted on the wheels and track.

Additional InformationHeel Divergence

• Heel divergence is the horizontal distance between the tongue rail and the stock rail at the heel end, which is the rear end of the tongue rail.

• It represents the total lateral shift the tongue rail achieves from its starting (closed) position.

Flange-way Clearance

• Flange-way clearance is the gap provided between the rail and the check rail or wing rail to allow free movement of the wheel flange.

• It ensures that the wheel flange doesn't strike the check rail or crossing nose during passage.

• It is a critical factor in the design of crossings and check rails, but not related to the switch angle.