So I am about to put an offer in on a great REO Triplex priced well below market. It must of been renovated by the previous owner before they defaulted. It is ready to rent other than a few minor repairs and maybe som...

Or is this a horrible investment because the net profit doesn't even equal the OPM I used?  

So, property prices falling isn't horrible for real estate investors.

It isn't a horrible idea.

The issue is that a train track runs behind it and the vibration is horrible (literally feels like an earthquake day and night).

If something horrible happens (like your handy man who you have given the keys to all the properties rapes your female tenant (you didn't know he just got out of prison for rape) (no insurance coverage for you by the way because intentional torts are uninsurable) you will lose everything you own.

I used my own personal cash savings which later turned out to be a horrible idea.

If you plan to be making less money in the future (when future depreciation would help m than today.) and your taxable income is well over $100k (otherwise you’re turning a 12-15% tax bracket in to a 25% tax bracket.) and your qualified as a real estate professional so you can deduct the expenses against your regular income (you spend more time in real estate than at any w-2 job with a minimum of 750 hours) and you can get it done for a $1,000 give or take and you plan to hold it for at least 10 years (or do a 1031 exchange) it’s probably not a horrible idea.

Good prospect in a horrible location, bad prospect in a great location....etc.

They can be horrible for an investor.