The national rail operator restored full service on the northern line after engineers cleared a signalling fault at a regional control centre that had disrupted travel for close to forty eight hours.
The fault was traced to a failed interlocking unit that forced controllers to move traffic manually through a section carrying both passenger and freight movements. Manual working reduced capacity on the section to roughly a third of normal throughput.
Effect on passengers
At the height of the disruption, more than ninety services were cancelled and a further two hundred delayed. The operator arranged replacement road transport between the four worst affected stations, though capacity fell well short of demand during peak hours.
Refund arrangements have been extended to cover all tickets booked for travel during the disruption window, including advance fares that would ordinarily be non refundable. Claims can be made through the operator for the next sixty days.
Manual working is safe, and it is slow. Those two things are related, and passengers felt the second one.
The operator said the failed unit belonged to an installation scheduled for replacement under the resignalling programme running through the next three years. Six of the eleven control centres on the route have been upgraded so far.
The regulator has asked for a written account of the incident, including whether the redundancy arrangements at the centre performed as designed. That report is due within a month.
