Rail bosses have upgraded Welsh Secretary Cheryl Gillan from standard to first class train carriages six times in the past 19 months, the Government said.
Mrs Gillan scrapped taxpayer-funded first class rail travel for herself and officials when she took office in May 2010.
But figures from the Wales Office show she was moved to the more comfortable seats on First Great Western trains, which run between London and South Wales, for "operational reasons" on half a dozen occasions.
Wales Office Minister David Jones said: "The Secretary of State and three officials did travel first class - at no cost to the Wales Office - as guests of First Great Western when they attempted to set a new record for the fastest journey between Cardiff and London, and on six occasions the Secretary of State and two officials have been upgraded, again at no cost to the Wales Office, for operational reasons."
Answering a written parliamentary question, Mr Jones added: "All tickets bought from May 2010 onwards for myself, the Secretary of State and officials have been for standard rail travel, which has resulted in a saving of £86,824 when compared to the previous year."
Mrs Gillan is reportedly set to quit the Cabinet unless the Government's proposed High Speed 2 rail route is switched so it avoids parts of her Chesham and Amersham constituency in Buckinghamshire.