A 'Scissor Crossing' to me (and the Peco Catalogue) is two cross-overs overlaid on each other so a train on either of two parallel lines can cross over to the other line regardless of direction of travel. I think what you actually need is, in Peco terms, a 'short' or a 'long' crossing, often called a 'diamond' crossing. Which you use is dependent on the point radius. The short crossing is used with small/medium radius points, the long crossing with large radius. All available in both 55 and 80 code rail.