55012 (D9012) "CREPELLO" lines up with 37128 inside the Crimpsall erecting shops at Doncaster Works on Sunday 19th August 1979. 55012 arrived at Doncaster with generator and traction motor damage on the 15th August and can be seen here minus both roof sections...
...A power unit and generator from
one member of the class at Doncaster Works on Sunday 19th August
It is most likely one of the units (425 or 435) destined to be re-fitted to 55012 which was present for generator and traction motor flash-over damage.