I followed your link to Deltic Chonicles 34C and found it to be vey informative as it listed duties that were exceptional. I typed "Cambridge" into the search box and the initial hit
D9015/9015/55015 was for D9015 Tulyar:
16.07.72
With yet another failure in service for 55015, this time on Sunday 17th July 1972 with the 1N29 18:00 King's Cross - Newcastle (the second failure in two days) the DME commented...
"following this second casualty in two days the locomotive returned to King's Cross where at test run to Cambridge, with technical staff riding, quickly showed up the defect. These two casualties illustrate the undesirability of returning a locomotive to normal service with no fault found".
18.07.72
1B66 15:33 King's Cross - Cambridge and 1B66 17:35 Cambridge - King's Cross.
05.10.73
1B66 11:30 King's Cross - Cambridge and 1B66 13:30 Cambridge - King's Cross.
I also discovered that the EE maintenance contract ended in 1966 but prior to that date all scheduled overhauls had been undertaken at Doncaster. That's not to say that the installed diesel engines or generators were not sent back to the manufacturers for refurbishment. I am unclear about that. I also found references to Darlington Works being involved.
What I ask myself is how on earth I managed to miss all the occaissions when the GN main line workings north of Hitchin were diverted via Cambridge. I recollect that my main aim in those days was to combine a day trip to Peterborough with a clandestine bunk of March shed, which i did innumerable times (I was always thrilled to find a visiting ex NER loco. Even then I would have seen ECML workings passing through March and Ely ... but I never did. Later, when I finally moved back to Cambridge in 1983, I did witness such diversions and somewhere I have photos of HST's passing through Cambridge (though they usually halted on the through road for a crew change - in my observational experience).
I followed up on Deltic Chronicles to find references to Pinza, the model that i have purchased, with this enquiry
Search results which combines D9007 with Cambridge though I have not had time to go through all the references yet.
Thank you for that link 34C. Hours of nerd type fun. When I am in my dotage (with this heat surely only a matter of a few weeks before I reach that stage) I will no doubt be tempted to match my notebook observations with the details in Deltic Chronicles ........... though restrictions on how much I am allowed to take with me into the nursing home may be a limiting factor. I do like to link my models back to the prototype railway as it adds much to the enjoyment of the hobby.
Best regards .................. Greyvoices (alias John)