These turnout specs include: 1. A 550mm (21 5/8?) Radius curve. 2. A simplified construction to allow for changing between Power Routing and Non Power Routing modes by changing the position of a screw on the backside ? a big timesaver for DCC modelers! 3. Manual version by default has no turnout engine mounted. The optional #2-503 & 504 Turnout Machines are required for electrification. These will replace the previous version of the HO Scale left and right hand turnouts, previous known as item numbers 2-850 and 2-851. HO Manual Turnout with 550mm (21 5/8″) Radius Curve ? Selectable modes (power or non-power routing)