We have always called opposite end joints as Square. We're using S 7 rail (14lb) at the Park and our sharpest rebuilt curve is exactly 46 foot radius. This is as sharp as we can get by with pulling over the rails by hand. Tricks used were staggered joints midway through the rail length, welding 2 sections of rail together and steel gauging bars at the joints. This proved to be troublesome and the other half of the "S" curve was done with 80ft welded lengths that eliminated joints on the entire length of the curve. Pulled over by hand and anchored until screwspiked in place by Trucker's load restrainers. Closer spacing of sleepers helps hold the curve alignment. That has now been the way to redo all our sharp curves.
This shows the previous attempts at bending the rails and the jointbars which did little to help the deterioration of the curve allignment.
There is one turnback curve in bad shape left to do, this is 300ft of rail and at a radius of 36 ft so until the Club comes up with a roller setup, it won't get done. The sharpness was dictated by the City so even though there is plenty of area to lay a wider radius it won't happen.