Thanks Rod. The posts you pointed me to were exactly what I needed. The Big Boy disassembles similarly to the Allegheny. Four screws hold the boiler on and two handrails in the front pop out. I was going to give up until your post appeared. Of course I had to take it apart two times (although the second time was simple after the first time). I installed the spring directly under the screw head but it should have gone under the gearbox bracket.
I am including links to the other two threads about the Allegheny in case anyone gets here for the Big Boy.
I took the advice of the thread to put things together before I proceeded. I had remove or loosened the side rods which was completely unnecessary. I had also removed a bunch of screws which also was unnecessary.
My Big Boy is running again. This forum is amazing. The wealth of knowledge available is fantastic. Thanks to everyone that participates in these forums.