Aylesbury Vale District Council has pledged another £100,000 towards fighting HS2 and petitioning for mitigation if the line goes ahead.
The council has already pledged £150,000 fighting the railway and has spent £130,000 so far with £65,000 on technical expertise and the other half on legal challenges.
The latest contribution brings the total amount pledged to £250,000.
By petitioning the Hybrid Bill the council will seek to secure mitigation for the Vale should HS2 go ahead. These could include noise and environmental measures to reduce impact during construction, preventing the loss of local amenities and measures to protect wildlife.
Council leader John Cartwright said: “This is the very piece of work that this authority absolutely must be part of. It’s all about getting a better deal for the Vale.
“The increasing numbers of sceptics can also only help as the proposals move towards the government decision.”
Labour leader and councillor Robin Stuchbury said: “This is about us actually trying to mitigate the actions of Whitehall. This money might reap massive benefits in the long term to prevent the damage and the upset.”
Conservative councillor Jackie Phipps said HS2 would cause damage when it is being built, too.
She said: “The petition stage is where we can have the most effect by letting the select committee know just how strongly people feel about it. People will suffer along the line during the construction stage as well as when it’s up and running.”