Islineclear3_1
Established Member
I believe most of the slam-door Mk1 third-rail units bar the "Greyhounds" and 4REPs balanced at about 88 mph on level track.
When a many of these units were introduced in the '50s and '60s the Southern Region 'officially' had an 85mph ceiling anyway.
Maybe officially, but I remember seeing lineside "90" signs enabling 90mph running and on the straight between Tonbridge and Ashford, doing the "ton" wasn't unheard of in a Cep