A method of modernizing an existing railway installation with a plurality of railway tracks and a plurality of track-side objects selected from a group of points, signals, train detectors and level crossings, the railway installation including an existing interlocking having a plurality of interconnected relays and implementing a defined control logic associated with the plurality of track-side objects in order to control railway traffic on the plurality of tracks, the method comprising:
- arranging a plurality of dedicated object controllers along the plurality of tracks and connecting a respective dedicated object controller from the plurality of dedicated object controllers with a respective track-side object from the plurality of track-side objects;
- arranging an interface adapter at the existing interlocking, wherein the interface adapter includes:
- an analog input configured to receive an electrical input from an external source, wherein the electrical input includes at least one of an analog input current and an analog input voltage,
- an analog output configured to output an electrical output to drive an electromechanical relay circuit, wherein the electrical output includes at least one of an analog output current and an analog output voltage,
- a bidirectional digital communication interface configured to communicate digital data according to a defined digital communication protocol, wherein the digital data includes (i) first digital data transmitted via the digital communication interface and (ii) second digital data received via the digital communication interface,
- an analog-to-digital converter coupled to the analog input and configured to generate a first digital signal representing the electrical input,
- a digital-to-analog converter coupled to the analog output and configured to generate the electrical output in response to a second digital signal,
- a programmable logic control circuit including a control program, and
- a power supply configured to supply electrical power at least to the digital-to-analog converter,
- wherein the control program is configured to:
- produce the first digital data from the first digital signal,
- transmit the first digital data using the digital communication interface,
- process the second digital data, and
- produce the second digital signal in response to the second digital data;
- interconnecting the interface adapter to at least one dedicated object controller from the plurality of dedicated object controllers using the bidirectional digital communication interface;
- interconnecting the interface adapter to the existing interlocking using the at least one analog input and the at least one analog output;
- controlling the existing railway installation using the at least one dedicated object controller from the plurality of dedicated object controllers and using the existing interlocking by communicating the digital data between the at least one dedicated object controller and the existing interlocking via the interface adapter;
- building a replacement interlocking in the vicinity of the existing interlocking, while the existing railway installation is controlled using the existing interlocking and the interface adapter, wherein:
- the replacement interlocking includes a further bidirectional digital communication interface configured for communicating the digital data according to the defined digital communication protocol, and
- the replacement interlocking implements a replacement control logic based on solid state controllers;
- interconnecting, once the replacement interlocking is built, the replacement interlocking to the plurality of object controllers using the further bidirectional digital communication interface;
- and
- removing the existing interlocking and the interface adapter.