Shipping container is your answer. Ugly as sin, but lots of bang for the buck, very secure and mobile (assuming you have the right equipment to move it). Check water ports and also semi truck yards for used items.
That being said, my company builds bridges. We deal with the railroads quite a bit. Their right of way is something they take EXTREMELY serious! Here are some of the things we have to work around and should give you an idea how crazy it can be to work with railroads. I know what is done is done, and I wish you the best but because of my own experiences, there is no way I would want to touch that property with a 100' pole.
- If we perform work within 75' of the tracks, we have to hire a dedicated flagman. This is a railroad employee that sits in the truck and "flags" our guys when a train is on the way. We have a small amount of time to clear and get out of the way of the train. This guy, and his truck costs about $1,250 per day for an 8 hour shift! We are required to pay this EACH day the flagger is required on-site.
- We have to submit engineered plans showing how we intend to prevent debris from falling on the tracks.
- If our equipment/trucks need to cross the tracks that is a separate plan with temporary protection over the tracks.
- Not to mention it takes an act of god sometimes to make a move across the tracks.
- Fast is not a word in their vocabulary unless you have f*cked something up and causing problems to their tracks.
Think big -- something that causes a small delay here, creates a chain effect across the country, literally. Consequently, this is why they are so serious and non-flexible in many of their ways. Be careful how you tread and don't think anything isn't a big deal with them, because it is likely a very big deal.
Which rail is it? Union Pacific? Burlington? Or a small local rail -- who can sometimes be easier to work with than the big ones?