You have to open your minds. LCL was considered 2nd class freight and was handled as part of the “Freight” operation on most roads.
Express was sort of the 1st class operation of the baggage department and included 'The baby chicks" as mentioned, fish, bees, pigions, and just about everything the couriers carry today. It was part of the "Passenger" department, and was included in the passenger consists with "Express reefers", express box cars(Usually with through steam lines in later years), and bagage cars.
The IPP&W is intending to start a proper operation of passenger trains with all the passenger operations, as soon as we have the crews to operate them. The passenger trains will be the only trains on the pike that will have a set time of arrival and departure at most stations. This time table will take into account switching of “Add-on equipment”, or the servicing of head end equipment at stations along the line.
Mail cars will be part of the 1st class trains, and will require special handling also.
RailOp may not give us direction on all of this, but it is easily figured out. I haven’t looked into it yet.