., but even if it does, that doesn’t mean it’d be profitable today.I did a bit of googling over this thinking that the railroad was trying to keep the minerals, especially coal and iron, for themselves because a lot of steam engines burned coal and the engines and tracks were build from iron or steel (which is mostly iron).

@Aaron Burns makes perfect sense.

You can't control his intentions, or what he did/didn't know, if its an honest mistake or not, or if the prior owner knew/didn't know so lets not focus on that, it's a waste of time and energy.

Not worth your energy.

When he changed the compressor, was it because the old one completely burned out?

The degree of the burn varies.  

For A/C, summer months will use more energy and less in the winter, and vice versa for heat, but you can spread the average across all months, similar to the programs energy companies manage so users don't have large swings in their bills season-to-season, and add this to the monthly rent for each unit based on square footage, # of occupants, etc.

@Lee Burns here is one that I've done recently.  

Projects get expensive if you have to burn through lots of extra materials and tools because you didn't know exactly how to do it.3) Prepare for and expect the unexpected costs!

@Aaron Burns.