I admit that in more recent times the name of the district did change 
Hi Carol

Oh dear, I'm feeling pedantic today

The full name of the Registration District has never changed (although its boundaries may have done). It was called Newcastle upon Tyne right from the start and is still called that today: this can be verified by looking at the various census 'enumeration district' pages available on Ancestry, and also at the Place-name index available on Genuki
http://www.ukbmd.org.uk/genuki/places/regindex2-1.pdf'Newcastle T' was simply an abbreviation used at one time in the GRO indexes, which is why it appears as such on freeBMD. Other abbreviations used for the name of this Registration District, and thus reproduced on freeBMD, were Newc. Tyne and Newcastle Tyne. These were never the name of the Registration District.
For the record on both FindMyPast and Ancestry Olga Buch's birth is indexed as being in Newcastle on Tyne R.D.
(By the way, I don't live in Newcastle upon Tyne, but I do live near the Tyne - in fact I can see a tiny bit of it from my window

)
Jennifer
