i straighten LGB R1 curves with a hammer.
i hold them over a slightly opened benchvice (for the railfoot)that is about 4" broad.
using a small hammer and a flat piece of iron, that fits between rail foot and railhead, i hammer them roughly straight.
using a steel L-angle, that is long enough, i revise, where i need to hit from which side, to make it perfect.
i allways do two pieces of track together. so i can use the two short rails for one straight and the two long rails for another, without cutting.
including the cutting of the sleeper connections it takes about fifteen minutes the pair.