The "Trib Train" was introduced in 1972 and ran until the early 1990s, measuring wheel/rail adhesion profiles around the BR network. It was hauled by the Railway Technical Centre's own locos, beginning with a Baby Deltic or Co-Bo until Class 24 97201 "Experiment" was introduced.
97201 was the staple motive power until the mid 1980s when a new livery was applied and a 31 used.
Electra's kit consists of overlays for the three vehicles, Auto-Trailer RDB975076, Monitoring Van RDB 999900 and Lab 11, RDB 975046. These are designed to fit on two Mk1 BSKs (not the new ones) and one VBA wagon.