CI╔ board members faced "psychological intimidation" if they asked awkward questions about the mini-CTC, a witness told the inquiry.
Mr Bill McCamley, a SIPTU worker-director on the board, gave evidence that other members tried to make him and a fellow worker-director feel that they did not understand the issue because they were not accountants.
He said it was suggested to them that what they were implying was unsubstantiated and should not be pursued in the interests of the company.
On one occasion "Mr McDonnell the late Mr Michael McDonnell, then CI╔ chief executive took me aside and said 'you are not doing CI╔ any good' and that the current Oireachtas inquiry that I was looking for was never going to happen".
Mr McCamley said he became aware that the mini-CTC was in serious trouble only at a board meeting on November 3rd, 1999.
Prior to that he had heard "vague rumours", mainly from railway workers who were asking him what was happening with the signalling system.
He said contrary to the minutes of the meeting on November 3rd, there was a heated discussion.
He and the other worker-director were very worried about the mini-CTC and "suspicious about the MNL people", the four CI╔ employees who left the company to work for MNL (Modern Networks Ltd), one of the contractors on the signalling contract.
He said the timing of their departure was strange, coming as it did "just as problems began to surface in relation to the delays in the contract".
He said he told the board he wanted an investigation and did not want a whitewash.
He was concerned later that PricewaterhouseCoopers (PwC), the consultants who were also CI╔'s external auditors, were to be employed to carry out the investigation.
"It was a tad too cosy for the kind of investigation I wanted. I wanted a completely independent inquiry. There were grave implications for CI╔ and our staff and it was important that whoever was responsible for the mess was identified."
A report was also prepared internally and presented to the board in June 2000 but Mr McCamley found it "very unsatisfactory".