For what it is, F4.5 through its zoom range, its worth a shot. At the very least if it is a poor lens, I have one to learn about optic repair on. With rail photography, itll be hard to get everything tack sharp with a fast moving object. Looking at the F stop in my copy of "The art of Railroad Photography" most of the photos are f4 to 5.6. There are a few non-train but railroad related photos with a higher F stop, but those are done from 50mm and wider.
mrred, where can I find information on how to lube lenses properly?