to permit lateral movement of the tongue rail

to maintain the two tongue rails at the exact distance

to ensure exact gauge at the toe of the switch as well as the nose of crossing

to prevent any vertical movement between the wing rail and nose of crossing

center line method

right angle method

isosceles angle method

none of the above

Vi cot(cc/2)

cot(oc/2)

cot(a )

Vi cosec(a/2)

1 in 8′/2

1 in 12

1 in 16

1 in 20

heel of the switch to the toe of the switch

heel of the switch to the theoretical nose of the crossing

toe of the switch to the theoretical nose of crossing

toe of the switch to the actual nose of crossing