A retention mechanism for a pair of bi-parting doors (12, 14) of a transit vehicle, the retention mechanism comprising: a first track configured to be connected to a first door of the pair of bi-parting doors (12, 14), the first track having a first end and a second end, wherein the first track is movable with the first door between an open position and a closed position; a second track configured to be connected to a second door of the pair of bi-parting doors (12, 14), the second track having a first end and a second end, wherein the second track is movable with the second door between an open position and a closed position; a first retention assembly configured to be connected to the transit vehicle and to retain the first track in the closed position; a second retention assembly configured to be connected to the transit vehicle to retain the second track in the closed position; a first engagement member connected to the second end of 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 second end of 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, wherein each of the first retention assembly and the second retention assembly comprises a retention hook configured to be pivotably connected to the transit vehicle, and wherein each of the retention hooks is pivotable between a retaining position in which the retention hook can engage the first end (32, 36) of the respective first track and second track to retain the respective first track and second track in the closed position and a releasing position in which the retention hook releases the respective first track and second track to move between the open and closed positions, and wherein each of the first track and the second track comprises an aperture (34, 38) defined adjacent to the first end (32, 36) thereof and wherein each of the first track and the second track is configured to be engaged at the aperture (34, 38) by the respective first retention assembly and second retention assembly. a first track configured to be connected to a first door of the pair of bi-parting doors (12, 14), the first track having a first end and a second end, wherein the first track is movable with the first door between an open position and a closed position; a second track configured to be connected to a second door of the pair of bi-parting doors (12, 14), the second track having a first end and a second end, wherein the second track is movable with the second door between an open position and a closed position; a first retention assembly configured to be connected to the transit vehicle and to retain the first track in the closed position; a second retention assembly configured to be connected to the transit vehicle to retain the second track in the closed position; a first engagement member connected to the second end of 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 second end of 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, wherein each of the first retention assembly and the second retention assembly comprises a retention hook configured to be pivotably connected to the transit vehicle, and wherein each of the retention hooks is pivotable between a retaining position in which the retention hook can engage the first end (32, 36) of the respective first track and second track to retain the respective first track and second track in the closed position and a releasing position in which the retention hook releases the respective first track and second track to move between the open and closed positions, and wherein each of the first track and the second track comprises an aperture (34, 38) defined adjacent to the first end (32, 36) thereof and wherein each of the first track and the second track is configured to be engaged at the aperture (34, 38) by the respective first retention assembly and second retention assembly.