Here's where I realize that I don't actually know as much about railroads as I like to think. I call myself a Conrail fan, and I don't know the answer. (Or maybe it's because; I know of the Trail Vans, and I never stopped to think why someone else might.)
Maybe it was at one time Conrail was the largest piggybacker in America.Years ago,CR ran 36 van trains on the system(in the 80's).No other Railroad,especially in the East,ran that many TOFC/COFC trains.Conrail set a record movement of containers(764,000)back in the late 80's.This traffic was inherited by CR from PC(PC was the reason the van trains were called Trailvans)Even to this day,go trackside and see how CSX and NS now have this traffic.Also,Conrail was having issues with D&H calling their trains TV's.On the Southern Tier, is was confusing to dispatchers as to which Railroad they were dealing with(not being funny about this).DH/NYSW trains were called DTV(DH) and NTV(NYSW)to avoid confusion.