A man has been found guilty of the manslaughter of four rail workers.
Connolly had denied all the charges
Four men - one from Cumbria and three from Lancashire - were working at Tebay, Cumbria, when a trailer ran out of control in February 2004.
Mark Connolly, 44, from Anglesey, North Wales, and Roy Kennett, 29, of Maidstone, Kent, had both denied four counts of manslaughter.
Connolly has been found guilty of four charges of manslaughter. The jury has yet to return a verdict on Kennett.
The four men who died were Colin Buckley, 49, of Carnforth, Lancashire, Darren Burgess, 30, also of Carnforth, Chris Waters, 53, of Morecambe, Lancashire, and Gary Tindall, 46, of Tebay.
Connolly was also found guilty of three counts of breaching health and safety laws and the jury at Newcastle Crown Court convicted Kennett of a single count of breaching health and safety laws.
The rail workers had no warning of the approaching wagon
The jurors are to resume their deliberations on the four counts of manslaughter against Kennett on Friday.
Prosecutor Robert Smith QC told the court Connolly was "grossly negligent" in his actions.
He said he had "scant regard" for railway safety and had deliberately disconnected the hydraulic brakes on two wagons.
He said the boss of MAC Machinery Services dismantled the brakes because it was cheaper than repairing the wagons properly.
Connolly had deliberately disconnected the brakes on the two wagons because both the hydraulic systems were in such a bad way they would not work properly in conjunction with a crane.
He then filled the cables connecting the wagons to the crane - which were usually full of hydraulic brake fluid - with ball bearings, giving the impression that everything was above board.
Bob Crow, general secretary of the Rail Maritime and Transport union said the incident was not an accident but the direct result of rail privatisation, with safety taking second place to profit.
He said: "Two years after Tebay, we still have a confusion of contractors, subcontractors, one-man-and-a-dog owner-operator plant-hire outfits, and a host of labour-only agencies.
"That means there is no consistent application of safety standards and no central line of command and communication."