PC Mark Dempster of the collision investigation unit told the hearing there was no evidence of ice on the road:
"To move a wagon of this size across the road would require a large piece of ice- in the nine minutes it took the emergency services to arrive that ice would still be visible"
"On the balance of probability as to why Mr McQueen failed to negotiate the left hand kink it is possible he became distracted."
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The man made off with a small amount of money, after threatening a female shop assistant.
A man and woman on a motorcycle were killed in the crash, which happened on the A76 in Dumfries and Galloway.
Damage to overhead lines means all trains between Carlisle and Lancaster have been cancelled.