Alliance coupler lock lifter securing arm

A latch lock mechanism for a railcar rotary-dump coupler is provided for an Alliance coupler having a more narrow inner housing cavity for the coupling mechanism than the standard coupler housing chamber, and the latch is operable to extend from a locklift assembly at a coupler and railcar inverted position to contact a top wall recess of the cavity to constrain the locklift assembly from movement past the lock thrower to thereby constrain movement of the lock thrower and coupler head, which latch maintains the coupler in a closed or coupled state at the inverted position.