I just noticed on a roster that the streetcar system in Philadelphia had 34 freight motors. Why? That's a pretty hefty number for any electric railway or interurban. Did they have any regular carload freight workings, or was it all LCL?
In the case of PRT, a Broad Gauge 5' 2-1/4" company, there may have been full carloads for one customer, but a lot was less than carload between freight stations. There was through interline service over Reading Transit & Light, track connection at Germantown & NorthWestern Aves. (City Limits). Apparently most other interline freight was transshipped, especially with the Standard Gauge Lehigh Valley Transit at Erdenheim and 5' 2-1/2" Philadelphia & West Chester Traction at 63rd & Market Sts. I don't know what the situation was with the other Delaware and Bucks County trolley lines, all Broad Gauge, many with freight service. Not all of the cars may have been in freight service at the same time, the last one was recently retired as line car D-39, much earlier it was a refrigerated freight motor.
Besides the freight cars, PRT also had dedicated newspaper and Mail cars; that could be called carload service. Milk cans may have been another carload commodity. Philadelphia & West Chester Traction did haul solid flat car loads of hay.