In a statement to the stock exchange on Wednesday, Balfour Beatty said: "We see no justification for manslaughter charges to be brought against our maintenance business or its former employees."
The company added: "The charge of manslaughter against our maintenance business will be firmly defended as we see no plausible basis for it in law or on the evidence. The individuals charged will have the company's fullest support in defence of the charges against them."
Four former BBRIS employees and the subsidiary itself have been charged with regulatory breaches of the Health & Safety at Work Act.
Four people from the then rail operator Network Rail have also been charged with involuntary manslaughter.