Swinney says work is under way on a competitive public sector bidpublished at 12:30 Greenwich Mean Time 7 February 2019
Mr Harvie says there is clearly a need for wider structural change, such as bringing Network Rail under the control of the Scottish government, "but we cannot wait for that".
The Scottish Green Party co-convener asks what preparation is being made for publicly owned railway.
Mr Swinney says if an operator of last resort was to replace Abellio in 2020, using the break clause, it could only be temporary.
He adds work is under way on a competitive public sector bid.