Computer-based interlocking is
railway signal
A railway signal is a visual display device that conveys instructions or provides warning of instructions regarding the driver’s authority to proceed. The driver interprets the signal's indication and acts accordingly. Typically, a signal mi ...
interlocking
In railway signalling, an interlocking is an arrangement of signal apparatus that prevents conflicting movements through an arrangement of tracks such as junctions or crossings. The signalling appliances and tracks are sometimes collectively ...
implemented with
computers, rather than using older technologies such as
relays
A relay
Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts
An automotive-style miniature relay with the dust cover taken off
A relay is an electrically operated swit ...
or
mechanics
Mechanics (from Ancient Greek: μηχανική, ''mēkhanikḗ'', "of machines") is the area of mathematics and physics concerned with the relationships between force, matter, and motion among physical objects. Forces applied to objects ...
.
General
CBIs are mostly implemented in two parts; a section that implements the safety and failsafe requirements, and a second section that implements "non-vital" controls and indications.
Brands
Different manufacturers have their own brands of CBI such as
*
SSI (Solid State Interlocking) -
BR,
Invensys
Invensys Ltd. was a multinational engineering and information technology company headquartered in London, United Kingdom. It was formed in 1999 through the merger of BTR plc and Siebe plc. It had offices in more than 50 countries and its produc ...
,
GEC-General Signal
*
Mircrolok II
*
Smartlock
* Germany - Alister CBI from Funkwerk IT
[ Railway Gazette International of July 2012, page 18]
Interface between different brands
When interfacing different brands of CBI equipment, it may be necessary to use relays of each regime, which are then hardwired from one to the other. This happens in the middle of the
Channel Tunnel
The Channel Tunnel (french: Tunnel sous la Manche), also known as the Chunnel, is a railway tunnel that connects Folkestone ( Kent, England, UK) with Coquelles (Hauts-de-France, France) beneath the English Channel at the Strait of Dove ...
where French and British signalling equipment meet.
Competition Rules
Since only some of the major signalling organisations make CBI equipment, it was agreed that to prevent other players being left out in the cold, CBI equipment would be made available to those players at cost.
References
Interlocking systems
Rail infrastructure
{{rail-transport-stub