RailCore® is a family of Core-XY based Reprap 3D printers designed by J. Steve White, Tony Akens, and Ben Withem.
10-15A SSR required.
You can get cheap chinese SSR’s for $2, but it is recommended to buy genuine/certified SSR’s from a known source such as RS Components or Farnell for ~$20 range. These are AC voltages, and you really don’t want to mess around.
Good makes are Crydom (Sensata-Crydom) and Panasonic.