The family was heavily influenced by the Class 202[clarification needed] locomotives built in the mid 1970s.

Class 27s were frequently engaged in pulling heavy freights from the Flemish ports to the sorting yard at Montzen, near the German border.

They also pulled a number of passenger services including peak hour trains of M5 double deck coaching stock.

Locos 2742 to 2760 have been modified with MUX and automatic couplers at one end so they can work in multiple in push-pull trains made up of two Class 27s each with a rake of five M6 coaches running one behind the other.

These locos have been showing frame wear because they were not originally designed for this kind of service so SNCB is monitoring them closely.