Luton South signal box on right, it appears to be working with D5019 and I do not think these were common on the Midland main line so may be a special especially as the new pair were allocated to Derby for a brief two months from July 1959.The Derbysulzers website says :"1959 The August bank holiday weekend saw a considerable use of Type 2’s (both the BR/Sulzer & Metro Vick types) out of St Pancras, being common on Derby & Nottingham services, frequently doubleheaded".