Grantham Canal Society's restoration fund has been given a boost of almost £7,000 thanks to the auction of two steam train plates.
The solid brass number plate and brass and steel nameplate from the Wollaton Hall, built in 1940, went under the hammer on Saturday.
It was estimated that the plates, owned by Peter Stone who is the secretary of Grantham Canal Partnership and also a trustee of the Friends of the Grantham Canal Society, would sell for £5,000.
But they almost tripled that figure to make £13,500, with the commission waived because the money was going to charity.
Mr Stone is donating the sum to be split equally between Grantham Canal and Derbyshire's Cromford Canal restoration funds.
He told granthampeople: "They did remarkably well to raise such a great amount – I'm extremely pleased.
"Almost certainly the £6,750 will go to buying and installing new bottom gates for lock 18 at Woolsthorpe which will cost in the region of £35,000.
"This money gives us an excellent start to an appeal to complete the work."
Mr Stone added that he hoped his gesture would encourage others to donate to the societies or volunteer.
The 33-mile Grantham Canal ran from the then market town of Grantham, through the Vale of Belvoir, to join the River Trent at Nottingham and served what was then an essentially agricultural community.
The canal is best-known for its towpath walks through stunning scenery – but leisure boating is also possible on the four miles between the A1 and Woolsthorpe. The purchase of 'Mudlark' and restoration of the Woolsthorpe flight of locks is also accelerating progress.