I believe the pictured car is IC 79000 — from IC series 79000-79031.
The following may be more information about these cars than you want or need: In the April 1945 IC List of Freight Car Equipment (an internal IC publication that included much other information) it shows 14 cars in the 79000-79031 number series. The covered hoppers are shown as having a capacity of 50 tons; an interior length of 22’-0”; and an inside width of 9’-5-1/2”.
I believe the 79000 series 50-ton covered hoppers were converted from IC USRA steel 50 ton, twin open hoppers.
The 1945 list shows the USRA 50-ton twin open hoppers in number series 65000-65958; there were 957 cars in that number series as of April 1945. The inside length of those cars is shown as 30’-6”; the inside width is shown as 9-5-1/2”. The difference in interior length between the open hoppers and the covered hoppers is, I believe, because new steeper slope sheets were riveted inside the converted covered hoppers to permit them to be self-clearing with cement lading — which requires a steeper angle in a self-clearing car than coal or gravel.
The July 1940 OER is the first one that I have that shows the rebuilt covered hoppers. It shows 14 50-ton covered hoppers in the 79000-79099 number series. It also shows 960 USRA 50-ton twin hoppers divided between the 210000-210999 and 65000-65959 series (a renumbering of the USRA twin hoppers was apparently in-process).
The 1943 OER showed 958 USRA 50 ton twin hoppers in number series 65000-65959 and 14 50-ton steel covered hoppers in number series 79000-79031.
The April 1946 showEd 954 USRA twin hoppers and 14 twin covered hoppers.
The October 1949 OER showed just 187 USRA twin hoppers in the 65000 number series and just 7 twin covered hoppers in the 79000 number series.
Any additional information on these cars would be welcome.