Movable machine room, elevator arrangement and method for constructing elevator

A movable machine room comprising

• a support platform, the support platform including one or more releasable mounting mechanisms to releasably mount the movable room in a hoistway;
• a hoisting machine mounted on the support platform;
• a working platform on top of the support platform, the working platform being a roof of the movable machine room and the working platform including handrails;
• and
• at least one support structure configured to support the working platform such that the working platform rests on the support platform, the at least one support structure being selectively actuatable to expand in a vertical direction to hoist the working platform higher above the support platform or to contract in vertical direction to lower the working platform towards the support platform,
• wherein the at least one support structure is configured to be actuated to cause the working platform to move in the vertical direction in relation to the hoistway while the support platform is stationary in relation to the hoistway and the hoisting machine is causing an elevator car to move to transport at least one passenger and/or good below the movable machine room.