For clarity, as Craig mentioned FEC's operating employees are represented by the UTU. The lockout lasted from 1963 to 1978, and was the result of a legal strike by the clerks union after FEC declined to accept the conditions imposed by a Presidential Emergency Board that had been accepted by all the other railroads. When the clerks union struck, most of the other operating crafts honored the picket lines, which was management's basis for locking everyone out. After the 1978 settlement, following some lengthy negotiations the UTU signed a so-called "Syetem Agreement" with FEC, which is much more liberal than those of other railroads. Included was a reduced manning agreement and an hourly wage.

According the Progressive Railroading article linked in the original post, FEC has not yet determined if it would operate the proposed servie itself or enlist an outside contractor. If an outside contractor is used, there would be no requirement that it be unionized.

From the article: "FECI has not yet determined what type of trainsets it will need to purchase or what firm will operate the trains."

For those interested in reading more about the strike and lockout, here's some good information: [caselaw.lp.findlaw.com]