RSK Business Solutions
Anerley Court, Half Moon Lane, Hildenborough, Tonbridge
Phone: +44 (0) 1732 833111
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Service Description

RSK Business Solutions Ltd have carried out the Signal Overrun Risk Assessment Process on a multitude of infrastructure change projects within the Rail sector as well as being seconded on a number of occasions to assist Network Rail with the existing layout assessments.

Following the 1999 Ladbroke Grove rail accident and the subsequent public enquiry, RSK Business Solutions Ltd worked with Network Rail to develop the Industry Standards for assessing the risk of a train to train collision following a SPAD (Signal Passed at Danger).

These Standards were released in 2001 and since then RSK Business Solutions Ltd have remained the Network Rail Appointed SORA (Signal Overrun Risk Assessment) Authority. In 2013 this SORA process received an overhaul and was updated with the implementation of the SORAT system which was designed, coded, tested and continues to be supported by RSK Business Solutions Ltd. This tool is now recognised as a verified tool within the Railway Industry Standards RIS-0386-CSS published by RSSB.

Since the release of SORAT the RSK Business Solutions Ltd Rail Risk Management/Assessment team have used the tool to assess more than 3,000 signals on both new infrastructure projects and existing railway (as of May 2016) which represents around 30% of all assessments completed within the system.

As well as providing SORAT risk assessment, RSK Business Solutions Ltd is the sole external training provider in the SORA process and is also the competent body that issues competence certificates to other assessors within the industry.


The overrun risk assessment process as shown below includes JST and PA assessments for early design optioneering as well as SORAT assessment at the single option detailed design stage. RSK Business Solutions Ltd can assist with every stage of the process and are currently the Network Rail appointed

Signal Overrun Methodologies

Key terms

  • SORA - Signal Overrun Risk Assessment.
  • SPAD - Signal Passed at Danger.
  • VariSPAD - A list of 16 issues which may alter the probability of a SPAD at a signal.
  • VariSPAD Workshop - An expert judgement workshop held to discuss the higher scoring signals.
  • Risk Rank - A banded Risk score required for a comparative analysis of the results.
  • FWI/yr - Fatalities and Weighted Injuries per year.
  • CBA - Cost Benefit Analysis.
  • SAT/DA - The previous methodology that was replaced by the SORAT system in 2013.
  • TPWS - Train Protection and Warning System.

Key Projects

  • Crossrail Western Approaches and North East Section

    Client: Network Rail Crossrail
    Scope: SORAT assesment of 300 signals between Paddington and Heathrow Junction and 200 signals between Stratford and Shenfield as part of crossrail project
  • Euston Station HS2 Enabling Works

    Client: Network Rail HS2
    Scope: SORAT assessment of around 70 signals within Euston Station under current and proposed layout for HS2 enabling works
  • Birmingham New Street Area Resignalling Phases 4,5,6 and 7

    Client: Network Rail
    Scope: SORAT assessment of over 200 signals under Phases 4,5,6 and 7 of Birmingham New Street Area Resignalling including New Street Station existing and proposed


AM Rail Group has worked closely with RSK’s risk assessment team on the Doncaster Connectivity project. RSK Business Solutions Ltd proved that they were able to deliver and adapt quickly to changes in scope that are inevitable at GRIP 3 and 4 design stage. RSK Business Solutions Ltd SORAT and Level Crossing risk team continue to support AM Rail Group on a number of level crossing renewals and re-signalling schemes and we look forward to continuing and strengthening this partnership in the future
Miles Hancock | AM Rail | Managing Director
Colas recently worked with RSK Business Solutions Rail team to provide SORA support on the Thameslink London Bridge Stage works. Colas, as part of the Wessex Capacity Alliance, also contracted RSK Business Solutions Ltd to provide Operational Risk Assessment expertise to the Wessex Capacity Improvement Project – Waterloo Approaches. Their staff have always been professional and courteous and have been reactive to the pressures of delivering such large and high profile projects. We look forward to continuing this partnership on future projects
CJ Lansom | Colas Rail | Operations Manager (Signalling) - Rail Systems

DEG Signal have contracted RSK Business Solutions Ltd on many occasions in order to provide Operational Risk Assessments for our GRIP 3 and 4 signalling design projects. RSK Business Solutions risk team have proved to be experts in their field and make themselves available to give advice whenever it is requested of them. When working with RSK Business Solutions Ltd we can rest assured that the operational risk elements of our projects are covered so that we can concentrate on our core design and project management functions and deliver our projects to the satisfaction of our clients. We would look forward to continuing our collaboration with RSK Business Solutions Ltd on future projects.

Russell Gell FIRSE  | DEG Signal | Engineering Director

Mott MacDonald has contracted RSK Business Solutions Ltd for over 10 years to support us with operational risk assessment on many of our signalling projects. Their team of risk assessors have proved to be competent, approachable and have always worked with us to achieve some challenging deadlines.

David Teasdel | Mott MacDonald | Railway Signalling Consultant Engineer

Babcock International (then First Engineering Ltd) first worked with RSK Business Solutions Ltd in 2004 on the West Coast Modernisation Project Line Speed Enhancements. Since then they have provided operational risk assessment support on many infrastructure and signalling projects of varying sizes. The RSK Business Solutions Ltd team have always been attentive to our requirements and professional in their manner. They continue to be flexible and committed to meet the deadlines of our projects and as the technical experts we know that RSK Business Solutions Ltd can be relied upon to provide the right advice at the right time. I look forward to working with the team on future projects.

Brad Thompson | Babcock International Group | Signalling Design Consultant

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