When were their last major overhauls? Was there a design flaw (or something) which affected the Cs? I would think that the answer is either that the Ts didn't need replacements while the Cs did (either due to wear, design, or retirement)...or that the Ts received the last replacements of the old type while the Cs were shopped later and received the newer parts. I doubt they'd make a point to change them over if they didn't have a reason other than to make them all the same.
Michael
Edited 1 time(s). Last edit at 03/15/2009 07:39PM by myork.