Rail boss Graham Smith concluded his evidence by insisting there was space for goods trains as well as passenger trains on the Midland Main Line.
He said the council's analysis that tried to prove south-bound freight trains would catch up with passenger services in central London, was based on a misunderstanding of how the Thameslink tunnel from St Pancras to Blackfriars operated.
The hearing has broken for lunch with his cross-examination due to start at 2pm.
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