[5] All Class 46s were delivered in BR Green with a broad horizontal grey stripe on the lower bodyside and small yellow warning panels on the ends.

From the late 1960s all were repainted into the corporate image Rail Blue, although repaints carried out at BR depots between works visits did vary and at least D138 (later 46 001) was recorded in Rail Blue with full yellow ends, but retaining the grey stripe on the lower body side.

Whilst seeing intermittent use on freight trains, Class 46s were regular performers on passenger turns, particularly North East-South West, Trans-Pennine and secondary North East-London trains,[2][8] and depot allocations reflected this with locos at Gateshead and Plymouth in 1977[9] giving a typical spread.

[10] In the 1980s, the remaining locomotives were concentrated at Gateshead depot, and the final booked passenger workings for the class were the dated summer Saturday services Bradford - Weymouth (between Bradford and Birmingham New Street), Newcastle - Plymouth, Newcastle - Blackpool North, and York - Blackpool North.

[6] On 17 July 1984, 46 009 (formerly D146), hauling three Mark 1 coaches, was deliberately crashed into a "Flatrol" wagon loaded with an empty nuclear waste flask and lying on its side.

At the point when the locomotive hit the flask it was travelling at about 100 mph (160 km/h), and the resulting impact was recorded and later broadcast publicly.

[13][14][15] The test was intended to demonstrate to the public that there would be no leak of radioactive material in the event of a rail accident involving a train carrying a nuclear waste flask.