AL6 Load Measuring Wheelset
| Following the introduction of
the Liner trains, which consisted of bogie flat wagons carrying various
lengths of containers, several track-buckling
derailments occurred in the late 1960's involving these vehicles 1.
In both the cases referred to, the cause of the track buckling was the incorrect installation of the then new Continuous Welded Rail (CWR) combined with the excessive hunting of the Gloucester three-piece bogies of the vehicles, which imparted excessive lateral forces into the track This lead during the early 1970's to the DM&EE successfully experimenting with a Load Measuring Wheelset (LMW) under a Freightliner wagon (see here). The LMW was borrowed from the R&DD who further expanded this area of investigation with the HSFV1 and later Decapod. Around the same period the AL6 locomotives, with their nose-suspended traction motors giving them a high unsprung mass, were knocking seven bells out of the WCML infrastructure and the locos were suffering from various problems themselves. One aspect of the larger investigation into the performance of these locomotives was the manufacture and fitting of a LMW to an AL6 locomotive for a trial period. The wheel set was very expensive as each spoked wheel was machined from a solid blank wheel. The author was a junior on the Testing Section at the time and was roped in to attach the myriad of strain gauges to the wheels. Gauges were attached to measure vertical, lateral and longitudinal forces - so there were a lot of gauges on each wheel. Once completed the wheelset was wired up into bridges and painted to protect it from the elements. |
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AL6 locomotive No:E3164 similar to the locomotive fitted with the LMW BR Official |
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The AL6 LMW - note the painted ID numbers on the 12 spokes. From the state of the wheel it looks like it has some way to go before completion. Author's Collection |
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The problem of passing the electrical signals from the rotating wheel was solved by the application of slip rings on each end of the axle. I remember that it was taken to the DB Testing Station at Minden West Germany for calibration - but I didn't get the chance of a trip there! This went to the senior engineers The wheelset was trialled on the locomotive for a period on WCML but was very problematical and the Project was eventually abandoned. 1 Track buckling derailments involving Freightliner trains occurred on CWR at Berkhamsted on 12th June 1968 and Auchencastle on 14th June 1968 |
