9 October 2018. And so it begins. Testing of the 'new' traction for the Marston Vale line has commenced. Vivarail 230003 comprises former London Underground vehicles 7069 now numbered 300003 and 7127 now numbered 300103. Carrying Marston Vale branding, 230003 stands at Bletchley on test working 5Q35 2035 Bedford -Bletchley TMD.