You used to recommend using a bench top belt sander for removing the base of the stock rail. Why can't I just do it that way?

When we first released our turnout assembly fixtures, we recommended using a small benchtop belt sander to sand off the base of the stock rail. This works well but tends to introduce a lot of heat into the rail, causing it to warp badly.

Filing the rail by hand is more gentle and introduces less stress into the metal. Also, using a StockAid tool is far more precise for this operation.