From memory of articulated engine installs I've done with Titan/Evo is that is a feature of these sound files...they can drift in and out the sync of both engines. It's the same as a double header with the same class of engines... Though there you have the prospect that one had new tires and the other worn and turned to a slightly different diameter... never to sync... And of course we can do that with a CV change...
Being around a the very birth of "electronics" for train control... the humble transistor(ized) throttle we would have gotten the the point of asking how can best get the locomotive to produce prototype sounds... from the locomotive...
This has to be corollary to Moore's Law... The neat and nearly impossible stuff doubles every two years...
