For more than a decade, Infrabel has been intensively modernising its signalling systems to allow more efficient route management and to offer control centre operators better support. In an initial phase, the operation will be centralised in 31 state-of-theart control centres. In a second phase, operations will be further centralised in ten control centres. In addition to the control centres, this goal can only be achieved by also changing a great deal of the existing interlocking equipment from wired to programmed interlocking. This article deals with the latter aspect. In different phases a greater standardisation of the external installation was achieved. We would like to share our experiences. As far as we are concerned, this is already a huge step forward in making the programme more efficient. This article aims to give the reader a highlevel insight into the standardisation steps and the level at which advantages and disadvantages are to be expected.