as well as possibly other equipment due to flashover damage. The transformer was also protected by a Buchholz relay which monitored any gas build-up within the cooling/insulating oil, as the acetylene (ethyne) gas generated is highly explosive. All Class 302 and 308 stock were fitted with Stone Faiveley pantographs for current collection from the overhead line. A particular oddity of Eastern/Anglian region EMU stock was the fitting of fibre glass snow shields between the pantograph and the supporting insulators. One member of the class, 302 302, was experimentally fitted with thyristor control in the early 1970s. After the experiment it was converted back to the original tap changer control, although the guard's van remained slightly different internally. Refurbished Units On refurbishment the trailer coaches were fitted with B5 bogies for both driving ends, along with conversions of the Battery Driving Second Open (BDTSOL) to a Battery Driving Trailer Composite Open (BDTCOL) having moved the first class accommodation to a position over the Westinghouse CM38 main compressor which was noisy and caused vibration, Driving Standard Compartment to a Driving Standard Open DTSO having removed the compartments for an open layout. The centre trailer had B4 bogies fitted with the Trailer Composite Semi Open (TCSOL) design converted to Trailer Standard Open (TSOL). The motor coach retained its Gresley derived bogies after refurbishment with compartments removed for an open layout with guards van. All 30 units would also receive gangway connections between cars within the unit. Originally the vehicles were insulated with blue asbestos which was removed and sealed during refurbishment between 1982 - 84 with some of the compartments being removed and reconfigured to open saloons. Units that received the original facelift with just Motor Brake Second (MBS) and the Driving Trailer Second (DTS) having their compartments removed for an open layout with the (TCSOL) not receiving any layout changes and keeping the Gresley bogies were: 202, 204, 205, 213, 215, 216, 217, 218, 220, 225, 226, 227, 228, 231, 232, 234, 236, 239, 245, 251, 252, 254, 259, 261, 262, 263, 274, 277, 279, 280, 283, 284, 285, 292, 293, 297, 298, 299, 300, 301, 303, 304, 307, 308, 311 The 30 units that received the full refurbishment and would last until withdrawal of 302s from service on LT&S were: Class 302/9 - non-passenger conversions The sub-classification 302/9 was used for seven non-passenger carrying conversions. Units 302990-993 were reduced to three-car