Machine Rooms can be located away from the Hoistway, but there are some provisions that need to be met. Here are a few of them. Grooved Fittings must be accessible for maintenance and inspection. A17.1-2013-3.19.3.2, Hydraulic Lines away from the Hoistway must be clearly marked. A17.1-2013-3.19.2.6. Piping outside of MR or Hoistway has to be protected, and if buried it needs either safeties,overspeed valve, or Plunger Gripper. There may be Local Building or Elevator codes involved also. It would be in your interest to throughly check.