I recently forged a sculpture out of 88lb bullnose track. I had 15' to heat in total. I built a rolling pipe forge and was able to heat about 3 foot to orange no problem. The rail just starts to sag under its own weight. The difficulty I had was loss of heat during the bending so I switched to an oxy/propane torch with an h5 head and a movable refractory enclosure. This set up works really well and cuts down on gas use. The bending I required was quite shallow but across the rail depth so a fair bit of force is required. I used 5 foot scroll wrenches made with excavator track pins 2" dia and welded them on to 2" scaffold tube. As usual as long as your heat is right it'll bend.
I've also split and bent 4 foot sections in my vertical forge no problem as long you cover the steal you won't go through to much fuel.
If you can get hold of an old asbestos fire blanket it'll work great with the gas set up as you can work all round the rail but a proper face mask is essential.
A few large fire bricks are a great investment.
Good luck and go do it.
