Investigation into the cause of failure of surge diverters on class 86 and 87 locomotives (TM-ETR-106)

Since their introduction, class 86 and 87 Locomotives have been fitted with primary side solid state surge diverters (Type BM32S) manufactured by E.M.P. Electrics. Other locomotives however, use horn arc gaps and electric multiple units use rod gaps. The reason for the introduction of surge diverters cannot be conclusively determined,...