Identify this

On the line running behind my house (an industrial spur serving wharehouses and light industry) I found this. I only recently saw it when the weeds and grass started to die back at fall. It is about 20 feet away from the track, and looks very old. I’m guessing it’s from PRR days. Does anyone know what this is? Mile marker? Speed limit? Something else?

Thanks!

Dave
there are milemarker posts left along the former B&O line here in Defiance. One farmer is nice enough to paint milepost 82 up. Milepost 81 is stuck deep in a ditch in a neighbooring feild.
stay safe
joe

We have some really old onesnear me that are concrete (I think) and are shaped like flat-sided tomb stones with rounded tops. The numbers are recessed and painted,or at least they used to be. Most of them are on the old Wabash/NYC which is now torn up.