OSL have rapidly established themselves as one of the leading independent signalling design and testing companies in the UK market and are currently working towards achieving similar status outside of the UK.


Signalling capability statement


An exemplary track record has led to OSL becoming the delivery partner of choice with many major rail industry companies on both the client and supply-side, including Network Rail, Jacobs and Signalling Solutions.

Link Up Approved

OSL is a UK rail industry Link Up approved supplier in a wide range of categories, including:

  • Design, Build, Test and Commission of Signalling Systems;
  • Design, Build, Test and Commission of Telecoms Systems;
  • Design, Build, Test and Commission of Power Systems;
  • Project Management and Consultancy Services Signalling

OSL offer a full range of services as part of a whole system rail infrastructure solution. This includes:


  • Signalling testing and commissioning;
  • Signalling design;
  • Signalling data preparation and principles and control table testing;
  • Verification and validation testing and management;
  • Functional testing;
  • Signalling maintenance testing;
  • Signalling bonding and immunisation;
  • Signalling equipment correlation;
  • Asset Surveys;
  • Signalling failure and fault rectification support;
  • Design management;
  • System engineering;
  • Project and programme management;
  • Project planning and project control;
  • Interface management and systems integration;
  • Project engineering and engineering management;
  • Construction and installation management;
  • Testing and commissioning management;
  • Bidding and supply chain management;
  • Independent technical advice and consultation;
  • Turnkey signalling related projects (including associated OLE, E&P, telecoms, P-way, civil engineering works, M&E and building Services) for works between £50,000 – £10 million+.

Engagement Mechanisms

OSL have experience of and are willing to participate in a full range of engagement mechanisms including:

  • Cost /Emerging Cost;
  • Target Cost (Pain/Gain – following a fully BS11000 collaborative approach);
  • Framework Call-Off;
  • Fixed Cost Lump Sum.

Products & Technologies

OSL have extensive experience in working with a wide range of railway control systems products and technologies including:

  • Mechanical;
  • Electro-mechanical: RRI and other electro-mechanical signalling systems;
  • SSI Interlocking systems;
  • CBI systems including ACC & Smartloc;
  • IECC, MCS and RCC control centre systems;
  • Modular Signalling Systems;
  • ERTMS systems;
  • Microlok.


In addition to our core business systems, OSL also operates a number of systems specifically beneficial to the rail industry:

These include:

  • Rail industry specific project delivery processes and procedures (design, installation, testing and commissioning, project management, finance, quality assurance, health, safety and environmental management, etc.);
  • IHS standards;
  • Hazard Directory;
  • Signalling Tracker and Test Log management System.