In mass transit scheduling, the number of precompiled potential shifts would be extremely large, usually more than the exponential of the number of potential spells. To solve the integrated vehicle and crew scheduling problem (ISP) without the aid of precompiled potential shifts, a spell-based integer linear programming (ILP) model is proposed. The model can deal with the ISP with multi-depots. The integrated vehicle and crew schedule is formed simultaneously by linking the spells and assigning depots to the spells during the scheduling process. The computational complexity of the model is finally analyzed. Experiments have shown the validity and efficiency of the model.