I made this
Look like this
Actually I had removed the boiler before straightening it but forgot to take a pic then, so I just took this one of the assembled engine. This is a 6-11152 Rio Grande LionMaster Challenger from 2009.
My brother-in-law, who collects and runs postwar Lionel, had done some research into the "cold-flow" properties of postwar boilers and came up with the idea for this straightening "vise." I wasn't sure that it would work on new "Chinese" castings but decided to take a shot as I figured there wasn't much to loose. Being cautious I originally cranked the bolts until I was getting a stiff resistance and left it that way for about 5 days while I was away. When I took it out I was amazed at how much it had improved.
So I stuck it back in, crank the bolts down all the way (about 1/2 a turn each every few hours over a couple of days), left it about a week and voila! Not perfect but incredibly good and hardly noticeable if you don't look close. I bought this bent cab $900 MSRP engine at auction for $323 delivered, and now it is one of my favorites.
Attached as a .PDF is a set of directions my brother-in-law provided for making the vise pictured above. Good luck and don't get stuck on the "bend." John