British Rail Class 506 was a locomotive commissioned by British Rail in England. It was an electric multiple units powered AC locomotive featuring the TOPS system. Logo of British Rail British Railways (BR), later rebranded as British Rail, ran the British railway system from the nationalisation of the Big Four British railway companies in 1948 until its privatisation in stages between 1994 and 1997. ... Royal motto (French): Dieu et mon droit (Translated: God and my right) Englands location within the British Isles Official language English de facto Capital London de facto Largest city London Area â Total Ranked 1st UK 130,395 km² Population â Total (mid-2004) â Total (2001 Census) â Density Ranked 1st UK... A wide variety of Locomotives and Multiple units have been operated on Great Britains railway network. ... The Total Operations Processing System, better known by its initials TOPS, is a computer system for managing the locomotives and rolling stock (railroad cars) owned by a rail system. ...