When I started on the MILW in the mid 60s we had Flexi-van service on both FRT and PSGR trains. Trains 57 train 1 and train 55 carried them as did trains 56 train 4 and train 58 between Chicago and the Twin Cities. I remember FRT train 72 would havethem between StPaul and Chicago. This might have been left-overs that missed eastbout Psgr trains don't know for sure.

All Flexi-Van service carried mail and express. There was a transfer that operated daily from CUS Chicago Union Station to LaSalle St Station for NYC trains Flexi-Van service.

Somewher around 1968 train 4 had a Flaexi-Van towards the hind end. Somewhere just east of the Brookfield,WI depot the chains let lose and the van started swiveling. If I remember correctly they could swivel around 180 degrees. Anyway...it took out every way side signal and crossing signal on the eastward track between MP 99 and MP 91. The bridgein Wauwatosa straightened out the errant van and upon arrival in Milwaukee depot the damaged van on flat was set out. The crew and some of us Hostlers were highly suprised. As luck would have it there were no opposing trains on the westward from Elm Grove in.The van looked like it had gone thru a war zone.