A method creates a reduced set of feasible transfers T(t, L′) for a trip t of line L, for each target line L′ from a set of all transfers from line L to all other lines, by computing, for each origin line L, feasible transfers between stations of the origin line L and a destination line L′; sorting the computed feasible transfers to create a transfer set T(L); determining, for each trip t of origin line L, and for each transfer in the transfer set T(L), an earliest trip t′ of L′ wherein the transfer is feasible; and adding, for each trip t of origin line L, the determined transfer from t to t′ to the reduced set of feasible transfers T(t, L′) when trip t′ is the only destination trip of the transfers in the reduced set of feasible transfers T(t, L′) passing at the destination station and when it is earlier than all the previous destination trips of the transfers in the reduced set of feasible transfers T(t, L′) passing by the destination station.