Photography is of course best anywhere in the early morning and late evening. Try to avoid the high sun anywhere you go.
Traffic in that area tends to be heaviest during those hours, luckily, and overnight. Many times Fostoria, Deshler, etc. will experience an afternoon lull. (Which is great for taking a nap when you've stayed up too late watching trains!) On the CSX Q351, Q393, Q165, Q109, and Q117 and generally reliable afternoon and evening westbounds this time of year. On Norfolk Southern the only reliable westbound in the afternoon or evening is 261. Eastbounds on the morning on CSX are pretty hit-and-miss, especially this far east. On Norfolk Southern, however, 218 and 234 are candidates to see in good light.