Sir Richard Branson, boss of the Virgin Group, will give evidence to MPs on the controversial re-awarding of the West Coast mainline franchise.
Virgin has run the line since 1997 but last month it lost the renewed contract to rival operator FirstGroup. Virgin has launched a legal challenge to that decision.
Sir Richard is expected to question the entire bidding process, when he appears before MPs on the Transport Select Committee. The committee will also hear from the Chief Executive of FirstGroup, Tim O'Toole. He is likely to defend his company's bid and argue that its plans are realistic.