GNR J52 0-6-0T No 68815 with a down freight leaving Grantham on 28 May 1955.
It's taking the Nottingham branch, but most likely only as far as Barrowby Road (whose distant signal is 'on'), there to propel its train along the siding to Ambergate Yard where there were several coal merchants, an oil and tar depot and the gas works.

Photo: J.P. Wilson / Rail Archive Stephenson