RAILTRACK'S ENTIRE Paddington signalling system, which includes signal SN109 at the centre of the investigation into last week's Ladbroke Grove train crash, had not been approved by HM Railways Inspectorate, NCE discovered this week.
A loophole in the law meant that Railtrack was able to operate the signals without approval from HMRI. To date inspectors have still not given the all clear for the remodelled signals.
At least 30 passengers were killed last Tuesday as a commuter train collided with a Great Western Intercity service heading into Paddington station.
A spokeswoman confirmed on Tuesday that the HMRI had raised serious concerns about the visibility of a number of signals on the approach into Paddington, not just signal SN109.
Inspectors had deferred the decision on whether to approve the signalling pending the outcome of the inquiry into the 1997 Southall crash. This accident left seven people dead and 147 injured and happened only 11km away from last week's crash site on the same stretch of track.
News that the signals had not been approved directly contradicts the impression given by Railtrack chief executive Gerald Corbett in statements since the accident. On Monday he claimed work to remove the flashing yellow lights at signal SN109 had been approved on March 17 this year, but did not mention that the wider system still had to be cleared.
The Paddington track and signal layout was remodelled in 1993 to accommodate the Heathrow Express service and reduce the number of slow trains having to cross fast tracks.
NCE has now discovered that there have been at least 22 incidents of signals passed at danger (SPADs) in the Paddington area since the remodelling, including an incident at SN109 in early 1998 where two trains avoided a collision by inches.
Signal SN109 has been passed at danger eight times since August 1993. But signal SN63 - part of the same system - at Subway Junction has been passed ten times since February 1994. Two other signals on the same system - SN41 and SN61 - have been passed twice.
Railtrack's press office said it could not comment on the story as zone engineers close to the Paddington signalling scheme were 'uncontactable' .
The loophole allowing the fatal signalling system to be used is contained in Section 4(4) of the Railway and Other Transport Systems (Approval of Works, Plant and Equipment) Regulations 1994. It allows works to be introduced without approval 'to avoid interruption'.
The HSE spokeswoman explained: 'New railways are not permitted to be brought into use before they are approved. However, for existing lines to be improved or updated there is a chicken and egg situation. The infrastructure controller always agrees design proposals with the Inspectorate but formal approval can only be given to the completed works. It is common for small items of detail to prevent final approval, although the works are in daily use.'
She also revealed that the HMRI still faces a shortage of approvals inspectors. In July NCE reported that it had been forced to increase the number of schemes brought into service without approval because of this shortage. It was looking to double its number of approvals inspectors from 12 to 24 (NCE 15 July) but since then has filled only three positions.
Paddington crash - pages 4,5, 6.