Transport of container handling vehicles between storage grids of different heights

An automated storage and retrieval system includes a first track system and a second track system. The first track system includes a first set of parallel tracks arranged in a first horizontal plane and extending in a first direction of the first track system and a second set of parallel tracks arranged in the first horizontal plane and extending in a second direction of the first track system which is orthogonal to the first direction of the first track system. The first and second sets of tracks of the first track system forming a grid pattern in the first horizontal plane including a plurality of adjacent grid cells. Each grid cell of the first track system comprising a grid opening defined by a pair of neighboring tracks of the first set of tracks and a pair of neighboring tracks of the second set of tracks. Storage columns are located beneath the first track system for storing storage containers in a plurality of stacks. Each storage column is located vertically below a grid opening. The second track system includes a third set of parallel tracks arranged in a second horizontal plane and extending in a first direction of the second track system, and a fourth set of parallel tracks arranged in the second horizontal plane and extending in a second direction of the second track system which is orthogonal to the first direction of the second track system. The third and fourth sets of tracks forming a grid pattern in the second horizontal plane including a plurality of adjacent grid cells. Each grid cell of the second track system including a grid opening defined by a pair of neighboring tracks of the third set of tracks and a pair of neighboring tracks of the fourth set of tracks. Storage columns are located beneath the second track system for storing storage containers in a plurality of stacks. Each storage column is located vertically below a grid opening. The first horizontal plane of the first track system and second horizontal plane of the second track system are arranged vertically displaced relative each other. The automated storage and retrieval system further includes a vehicle lift device for transfer of at least one vehicle arranged on the first track system to the second transfer system and vice versa. The vehicle lift device includes a platform arranged to carry the vehicle and a lift mechanism arranged to move the platform between: a first lift stop position establishing access between the platform and the first track system for enabling rel