<sod >Members of the Rail, Maritime and Transport union who work on the Central Line will walk out at 9pm on Wednesday Mick Cash, RMT general secretary, said: âRMT negotiators have made strenuous efforts through the Acas machinery to resolve this dispute but the door has been slammed in our faces.< eod>< sod > Members of the Rail, Maritime and Transport (RMT) union who work on the Central Line will walk out from 9pm on Wednesday.< eod>