When a long-established industry claims it cannot afford to renew one of its vital systems, something is clearly awry. Back in 1998, Railtrack Chief Executive Gerald Corbett told me the company could no longer make a business case for renewing signalling: a policy of patch and mend life extension showed a better Net Present Value.
Concern over signalling costs did not go away with the arrival of Network Rail. The focus for cost reduction was the labourintensive mechanical signalling on lightly used lines.
Around 2007-08 this resulted in a challenge to the signalling majors to develop a lowcost modern equivalent. This proposal was known as Modular Signalling, or Modsig for short.