WORK is continuing to solve software faults which have dogged the testing of ScotRail's new Class 380 electric units.

The operator has refused to accept the new Siemens fleet in its present state after a number of failures, having suspended commissioning on 24 September.

Siemens said some problems were ‘perfectly normal’ when new trains were tried out on actual routes rather than its test track, and remained optimistic.

But the difficulties with the 380s, costing £200 million, are sounding an ominous note because they are essential for December's new timetable.

The new units are due to enter service on the Inverclyde, Ayrshire Coast and Renfrewshire routes, displacing Alstom Class 334s which can then be cascaded to the restored Airdrie-Bathgate line.

It is now possible that the new route, which has been restored and electrified at a cost of £300 million, may be launched in December with a reduced service, because of the potential lack of trains.

A spokesman for ScotRail said: “We advised the manufacturer that all commissioning had been suspended and that we could not operate or accept these trains.

“We resumed running after modifications to the trains but will not accept them until all the problems are resolved and reliable operation is proven. We are in constant contact with the manufacturer and monitoring the extended commissioning trials.”

The spokesman predicted that the new Airdrie-Bathgate route would still open on 12 December, but with an ‘introductory’ service rather than the full timetable.