I am new to n scale trains.  I bought your Yard Boss train set which has a 0-6-0 engine and came track to make a 24".  Here are my questions:

1.  Is this track considered an 11.5" radius? 

2.  If not 11.5" radius, what is the radius?


I plan to add 15" of straight track at two of the arcs and another and two of 5" straight track at the other arcs. 

3.  Will your 2-6-6-2 stream mallet be able to negotiate this set up?

4.  If no to Q3 what radius do I need?