Greaseball's Gang are diesel engines, bullies who back up their boss at all times. They open the show, skating in formation with helmet lights piercing the dark. The gang all appear near identical and menacing.
In the original production, the three gang members with spoken lines were named "Tank", "Gook", and "Lube".
The actors who play the gang also usually play the National Engines, Freight, and Components. The Gang also turn into the track Marshalls. It is debatable whether Trax are included in the Gang.
The Gang costumes are generic black diesel engines, lacking any particular eye-catching features. The Broadway-style costumes originally featured the Confederate Flag on the chest, and subtle coloured details to differentiate the costumes close-up. The Confederate flag was removed in 2017 when its political significance had been highlighted in world events. Originally the Gang had wigs while not wearing their helmets, these were phased out during the 1990s.