Switch angle depends on i) heel divergence ii) length of tongue rail iii) flangeway clearance iv) throw of switch The correct answer is A. (i) and (ii) B. (ii) and (iii) C. (iii) and (iv) D. (i) and (iv)

The correct answer is A. (i) and (ii).

Switch angle is the angle between the two rails of a railway track at a switch. It is determined by the heel divergence and the length of the tongue rail. The heel divergence is the angle between the two rails at the heel of the switch, and the length of the tongue rail is the length of the rail that projects from the heel of the switch. The flangeway clearance is the distance between the flange of the wheel and the inside of the rail, and the throw of switch is the distance that the tongue rail is moved from its normal position to its extreme position.

The heel divergence and the length of the tongue rail are the two main factors that determine the switch angle. The heel divergence determines the maximum angle that the switch can be turned, and the length of the tongue rail determines the minimum angle that the switch can be turned. The flangeway clearance and the throw of switch are not factors that determine the switch angle.

The switch angle is important because it determines the amount of space that is available for trains to pass through the switch. If the switch angle is too small, trains may not be able to pass through the switch without derailing. If the switch angle is too large, trains may not be able to maintain their speed through the switch.