Signaling is the keystone of the railway transportation system and besides it, the interlocking system acts a central role granting the key issues such safety of the overall system.
In order to develop a new Interlocking System, in addition to study the interlocking principles and to have a reasonable background in computer based architecture we have to learn from the state-of-the-art of the existent railways vendor's proposal.
To cover the topic, this report brings together all the main aspects which relate to a choice of ones of the most used Interlocking Systems in Europe.
This include the overall architecture, fault resilience policy, software used to implement the main functions and to interact with railway operators.
Being SIL4 classified systems, they have some commonly features such as:
? the development process have to follow V&V model;
? formal methods to specification, validation, verification is mandatory.
It is also noticed that the interlocking logic: the core issue - is generally an abstract model of the relay circuit due the well-established railway's engineering knowledge. Indeed the main dialect is the ladder diagram or one to one translation from Boolean equation to code.
Conversely some newer systems use the new paradigm of object oriented design which leads to use an object model diagram ( and relative tools to generating code ) such as Harel's statecharts or proprietary language like ObjRail.
The document is structured in three major section with relative subsections:
-- Railways vendor's Interlocking
o Signaling solutions SSI
o Siemens (Ex-Invensys) Westrace
o Invensys Westlock
o Alstom Smartlock
o Ansaldo STS Acc
o AZD Praha Esa 33
o ECM HRM9
-- Other systems
o Thales Elektra
o Prorail Movares
o Bombardier Transportation Ebi-lock
-- Final consideration
Axmedis ID
urn:axmedis:00000:obj:1d485e7d-5f12-4bb9-8fca-ee16be1ee1cc
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