Rapido Trains N 905008 BR 97281 Class 28 Metro-Vick Co-Bo D5705 RTC Blue & Red Livery
Needing regular motive power for its test train programme the Railway Technical Centre acquired Class 28 Metro-Vic D5705 in 1968, primarily to work the Tribology Train or Trib-Train. It retained its BR green until it was transferred to the Western Region in the 1970s for further service as a carriage electric heating unit.
Subsequent RTC locomotives carried distinctive liveries and 97XXX series TOPS numbers. So D5705 is presented here in the blue and red livery carried by the class 24 and 46 locomotives later employed on RTC duties.
Tribology is the science of interacting surfaces in relative motion, including the effects of friction, wear and lubrication (eg. surface contamination).
The RTC Tribology Test Train was designed to allow the wheel-rail interface to be investigated and studied in a scientific manner under 'real world' conditions. A VAA-type van was constructed with independent braking of the axles, allowing braking loads to be applied to the wheels up to the limit of adhesion and thereby measuring that limit and obtaining data on the wheel 'slip/slide' conditions. The train ran over the same routes repeatedly, allowing the scientific measurement of changes in adhesion characteristics due to rail wear, weather, ambient temperature and seasonal environmental contamination (eg. leaves on the line) on the same sections of track.