Liberty Industrial Spur

[FCIN]

That might work, every time I go to the LHS I look at all of those steam-era cars and wish I could use those, my only concern would be it's impact on operations at the container plant.

Lots to consider if you choose to model the mid 60's. You've probably got cars right now that would be totally out of place for that era so you couldn't use them unless that just isn't an issue with you. Looking at the two photos you posted on Oct 7th, I see a Conrail Centerflow covered hopper, a box car in the Family Lines scheme and a bulkhead flat that would be out of place. There may be others that I just can't see in the photos.

You could of course use 40ft box cars for shipping your scrap paper. You railroad might have purchased a few of them for just that purpose. But keep in mind, depending on the era you choose, those cars might all have had their roof walks and full height ladders removed. If your era is prior to 1966, then all your cars would have full height ladders and roof walks, so a mixture of cars with and without would not be correct. You also have to watch out for appropriate road names too along with whether or not a certain type car existed in your era. No CSX (1980), SCL (1967), CR (1976), BNSF (1996), BN (1970), PC (1968), to name a few. But you would have plenty of interesting road names and paint schemes to choose from such as NYC, PRR, CBQ, SP, SOU, LN, ACL, SAL, and many others.

I've run in to that "what road is correct for my era" problem myself where I have about 10 cars that are painted for railroads that didn't exist in 1979-80 - but they'll get new paint jobs and lettering when the mood strikes me. I also have one L&N 50ft cushion underframe box car that I really like, but it still has roof walks and full height ladders. I can modify it like the prototype did, by removing the roof walk and cutting down all the ladders except the B end ladder , but then I have to plug all the holes in the roof and some where the ladders were and try and match the paint. Not sure it's worth the trouble.

Finally, you might just have to consider an entirely different main industry for your railroad. Plenty of potential ideas floating around out there (or should I say on the-gauge.net). Just a matter of picking something that would be believable and still have a good amount of operational interest.