A retention mechanism for a pair of bi-parting doors of a transit vehicle includes a first track connected to a first door of the pair; a second track connected to a second door of the pair; a first retention assembly connected to the transit vehicle and configured to retain the first track in the closed position; a second retention assembly connected to the transit vehicle and configured to retain the second track in the closed position; a first engagement member connected to the second track, the first engagement member being configured to engage the first retention assembly to cause the first retention assembly to move to retain the first track in the closed position when the second track is in the closed position; and a second engagement member connected to the first track, the second engagement member being configured to engage the second retention assembly to cause the second retention assembly to move to retain the second track in the closed position when the first track is in the closed position.