National Express, the transport group, is suing insurer CGNU over the losses it incurred after the Hatfield rail crash.
The train and bus operator said its lawyers, Barlow Lyde Gilbert, had served a writ on CGNU claiming the insurer was liable for substantial damages under a "business interruption"policy that it wrote.
National Express said it is covered for the loss of revenue growth due to the crash for three years from the date of the accident.
Prior to the crash, revenues were growing at 10% per year. They are now back at pre-Hatfield levels but revenue growth has ceased.
