MTC - fictional characters in:

* The Life and Death of Colonel Blimp

In the general shake-up that followed Dunkirk Clive is relieved of his command. He feels old and useless, but his friends Theo and "Johnny" (Deborah Kerr), a girl in the Mechanised Transport Corps, in whom he again sees a likeness to his beloved Edith, suggest there is still one way in which he can serve his country - The Home Guard.
http://www.powell-pressburger.org/Reviews/43_Blimp/Synopsis.html

* Foyle’s War

Vicar's daughter Samantha Stewart was transferred from the Mechanised Transport Corps to become a very unconventional driver for Foyle.
http://www.foyleswar.com/people/stewarts.htm