The firm behind the high-speed rail (HS2) route has shown "disregard and complacency" to Warwickshire, the county council said.
The Conservative-run authority has written to the government over "additional route details" it said were only revealed at a community meeting.
Deputy council leader Bob Stevens said they included plans to repair trains at a maintenance loop in Priors Hardwick.
The government said HS2 Ltd was using the meetings to pass on such details.
HS2's first phase, between London and Birmingham, is scheduled to be running by 2026, after the project was approved by the government in January.
The government said the line was needed to link cities and boost the economy.
However, in the letter to Transport Secretary Patrick McLoughlin, Mr Stevens demanded "more transparent and meaningful dialogue with HS2".
He said there was "concern and dismay" in the village of Priors Hardwick over plans for the maintenance site, which were revealed by engineers at a community forum meeting.
'11th hour bombshell'
The letter expressed concern at the "apparent culture of disregard and complacency within the HS2 Ltd organisation towards Warwickshire".
"We are dismayed at the recent announcements, including an 11th hour bombshell that Priors Hardwick is to face the additional burden of a maintenance loop, along with the news that Warwickshire will now have six, maybe even seven, construction compounds," Mr Stevens said.
"The way this information has been revealed undermines the credibility of Warwickshire County Council."
The council is opposed to the HS2 scheme, which it says could ruin the county.
The Department for Transport said HS2 Ltd, the company it set up to deliver the high-speed link, was holding regular meetings "with all the affected communities and local authorities" along the line.
"As the design of the route develops from the one that was announced in January, these meetings are an important way to report back on issues such as the need for and location of maintenance loops and possible construction sites," a spokesman said.
He added HS2 "had a commitment" to put new information to communities and councils in the forums as early as practicable so they could share their views.