Dumfries and Galloway MP Russell Brown is to meet with representatives from Abellio to ask for further information on its plans for the region.
The Dutch firm, which was awarded the ScotRail franchise by the Scottish Government in October last year, has agreed to meet the MP on 6 February.
Mr Brown said he will be highlighting concerns over proposed changes, including plans to reduce the number of direct services to and from Stranraer, as featured on the front of The Galloway Gazette last week.
He will also raise concerns that improved services on the Nith Valley line will not come into effect until 2017.
Mr Brown said: “There are a number of positives from the franchise such as the introduction of two hourly services from Stranraer but the loss of direct services to and from Glasgow is deeply disappointing.
“Unfortunately, the Scottish Government has now awarded the franchise so has agreed with these cuts, therefore overturning them will be difficult.
“However, I will nonetheless make the case for the provision of at least three direct services between Stranraer and Glasgow a day – including a service from Stranraer in the morning and a late night service back from Glasgow in the evening.”
Mr Brown added: “I am seriously worried that the electrification of services in the rest of Scotland but very little investment in the South West will leave our region even more marginalised than it currently is.”