Length 1/2 of a Marklin 2231= 15°. Radius 424.6 mm / 16-3/4". Marklin refers to this as a R2 K-Track curve.

Momentary contact with locomotive/car pickup shoe.

Same length and radius as a Marklin 2233. This means 2 pieces (a Marklin 2230 & 2239) are equal to 30 degrees and would replace a Marklin 2231, and 6 pieces make a quarter circle.