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<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">Computer-based interlocking</span></span>
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<p><b>Computer-based interlocking</b> is <a href="Railway_signal" title="Railway signal">railway signal</a> <a href="Interlocking" title="Interlocking">interlocking</a> implemented with <a href="Computer" title="Computer">computers</a>, rather than using older technologies such as <a href="Relays" class="mw-redirect" title="Relays">relays</a> or <a href="Mechanics" title="Mechanics">mechanics</a>.
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<div class="mw-heading mw-heading2"><h2 id="General">General</h2></div>
<p>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.
The European Union is working towards an EU standard within this area, called <a href="ERTMS" class="mw-redirect" title="ERTMS">ERTMS</a>.
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<div class="mw-heading mw-heading2"><h2 id="Brands">Brands</h2></div>
<p>Different manufacturers have their own brands of CBI such as
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<ul><li><a href="Solid_State_Interlocking" title="Solid State Interlocking">SSI</a> (Solid State Interlocking) - <a href="British_Rail" title="British Rail">BR</a>, <a href="Invensys" title="Invensys">Invensys</a>, GEC-General Signal</li>
<li>Microlok II</li>
<li><a href="Smartlock" class="mw-redirect" title="Smartlock">Smartlock</a></li>
<li>Westlock</li>
<li>Germany - Alister CBI from Funkwerk IT<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup></li></ul>
<div class="mw-heading mw-heading2"><h2 id="Interface_between_different_brands">Interface between different brands</h2></div>
<p>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 <a href="Channel_Tunnel" title="Channel Tunnel">Channel Tunnel</a> where French and British signalling equipment meet.
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<div class="mw-heading mw-heading2"><h2 id="Competition_Rules">Competition Rules</h2></div>
<p>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.
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<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>
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<li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><a href="Railway_Gazette_International" title="Railway Gazette International">Railway Gazette International</a> of July 2012, page 18</span>
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