Maintenance firm Metronet went into administration in July 2007
A union has warned of "potentially disastrous" safety risks over London Underground (LU) plans to cut its spending on maintenance by £60m.
The Rail, Maritime and Transport Union (RMT) said the cuts would also put "yet more" Tube staff jobs on the line.
But an LU spokesman said the cuts were efficiency savings made after Transport for London took over Tube maintenance from collapsed private firm Metronet.
He said: "We are reducing the costs but not cutting any maintenance work."
Metronet was upgrading nine London Underground (LU) lines before it went into administration in July 2007.
The RMT said £26.1m would be cut from track and signal maintenance, £18.9m from fleet and train maintenance and £18.5m from stations on lines formerly maintained by Metronet.
RMT general secretary Bob Crow said: "These are real cuts that will hit track, signals, trains and stations maintenance as well as putting yet more tube staff jobs on the line.
"The consequences of these kind of cuts on the underground could be potentially disastrous."
An LU spokesman said the cuts would be made as Transport for London (TfL) reduced back office roles duplicated by TfL and Metronet.
LU managing director Richard Parry said there was "absolutely no truth" in the RMT's claim that safety standards had been reduced on the former Metronet lines.
"Following its transfer to London Underground virtually all measures have improved, including the service for Tube passengers," Mr Parry said.
"Metronet's costs had spiralled out of control and to claim that the £2.5bn we have managed to save fare and taxpayers can be equated to a reduction in safety standards is wholly untrue."
A National Audit Office report revealed that Metronet's collapse cost taxpayers up to £410m.
Last week the RMT staged a 48-hour Tube strike over pay and staffing on the Underground.