“About half of what we do goes out on rail, and now we’ve had to find a total of 300 to 350 [road] trucks a day, so we’ve had to find an additional 150 trucks a day just to ship Nucor materials,” Petersen was quoted saying.

Norfolk Iron and Metal and the Louis Dreyfus Ethanol plant also had to bring in additional trucks to ship their products out.

The RAIB’s preliminary examination identified no evidence that the condition of the signalling system or the track contributed to the accident.

As a result of the accident, both main road and rail routes to Oban from central Scotland remained closed for an extended period, due to “major issues” in removing the derailed train. A 1,000 tonne crane was brought in from Cumbria to lift the leading carriage, which was left hanging over an embankment. Engineers had first to ensure the crane could be safely supported by the adjacent A85 road – “effectively a bridge on stilts over the northern edge of Loch Awe”. The crane lifted the front carriage on to a road low-loader while the rear carriage, which remained upright but above the track, was lifted on to a rail wagon. A spokesman for Network Rail said it was a “very complex operation”

According to the RAIB’s preliminary examination, the boulder fell down a slope onto the railway from within Network Rail’s boundary. There is a system installed at the accident location to warn drivers of approaching trains of fallen boulders but this is only operated by falling rocks or boulders from outside Network Rail’s boundary and therefore played no part. There was no evidence that the condition of the train, signalling system or track contributed to the accident.

A temporary timetable was put in place until the train could be recovered. A replacement bus service operated directly between Oban and Glasgow Queen Street and other buses ran from Crianlarich to Oban via Ballachullish, according to the Edinburgh Evening News

The trials are being led by aerospace research agency Deutches Zentrum für Luft- und Raumfahrt (DLR), which is providing researchers from its institutes for transportation systems and robotics & mechatronics. DLR partnered with train operator Bayerischen Oberlandbahn (BOB) for the trials – BOB offered use of an Integral dmu and crew. The other vehicle used was DLR’s own “RailDrivE” road-rail unit.

“RCAS is a system for preventing train collisions that operates independently of other safety technology deployed alongside the railway track”, Professor Dr Thomas Strang, project director at DLR explains. The DLR researchers delivered lectures and showed models to participants during a day of demonstration on 11 May. Observers were able to travel on the Integral, which was equipped with RCAS to communicate with the road-rail vehicle.

The two trains simulated three scenarios: one where the two were running alongside each other, simultaneously approaching a section of single-track line. In the second, one train headed for a set of points beyond which one route was occupied and the other clear, but the setting of the points was unclear. In a third test run, a train was left stationary near a set of points but did not constitute a hazard, and the system successfully recognised this.

In all cases, RCAS assesses the situation automatically. If it detects a conflicting move, the RCAS onboard interface prompts the driver to apply the brakes.

“RCAS is initially intended for routes and situations where, at present, no other protection systems are employed – for example, routes with very low volumes of traffic, industrial railways, construction sites or shunting areas”, according to Dr Michael Meyer zu Hörste, a DLR rail transport researcher. RCAS is in no way intended to replace ERTMS, he added. “It is an add-on system – RCAS can act as a safety overlay in places where conventional technology is not being employed.”

According to DLR, the existing prototype is based on “standard commercial hardware and software”, which in its existing form does not hold official approval for safety-critical fields of operation, and this will not be sought.