Okay, let me make this as simple as possible so I can decide to do it this weekend or forget it.

Upper Floor of two stories. Boiler supplies 100-120 units.

1. Can a hot water cast iron radiator with one valve and a valve at the basement feeder. Be removed just by closing those valves?

2. If not, does that mean that the water circulates opposite of the valves? Please, explain how the system circulates on one line?

3. I posted that it dead-ended at my last radiator, but I looked again and saw that the asbestos insulation was missing on the top at the end and now I see a 45 elbow going through the ceiling\wall into the garage space or a crawl space.

This is NOT a job that I call hire a contractor for. I must pay a $50 application fee, the contractor must go first to the maintenance office, register and then take a maintenance person to the job and explain the procedure that he intends to follow.
Only THEN, do they tell him if he can do the job. Because, they try to discourage outside contractors, they often find some fault.
They also lowered the in-house cost $25 initial hour, $15 all additional (they do not break a sweat) to encourage using their people who are hired off the street.
I have never had a job done correctly, the first time. Why should they care? They are on the clock if they have to come back!

So it's either me or it's nobody
Thanks
Mike Mc