referring to the drawing , there is illustrated a tool for installing elevator hoist machines in an elevator hoistway . the tool or system has been found to be particularly useful to lift , lower , and position a hoist machine in a hoistway that does not have a conventional machine room . the illustrated embodiment consists of a structural frame 10 adapted to be assembled around an elevator guide rail 12 designed to extend vertically within an elevator hoistway . the elevator guidance system may be of the type manufactured and sold by schindler elevator corporation and designated as a tri - rail elevator guidance system . in such a system , the structural frame 10 is assembled around the three rails of a tri - rail elevator guidance system . the main frame 10 includes vertical upright members 14 and guide shoes 16 . the guide shoes 16 typically interface with the guiding surfaces of the rails 12 to provide for relative vertical movement of the upright members 14 on the guide rails 12 . the main frame 10 also functions as a guide means for the carriage 22 and includes spaced apart guide members 18 connected to the vertical upright members 14 and containing guide shoes 20 coupled thereto for relative horizontal movement thereon . a hoist machine carriage 22 is connected to the guide shoes 20 . the carriage 22 includes horizontal base members 24 coupled to the guide shoes 20 , upstanding vertical members 26 , and an upper frame 28 integral with the upper ends of the vertical members 26 . the carriage 22 is provided to support a hoist machine 30 . the hoist machine 30 includes a base 32 to be permanently affixed to a machine support 34 mounted on the upper terminal ends of the guide rails 12 . in order to impart vertical movement to the main frame 10 and the associated hoist machine carriage 22 , there is provided an attachment means in the form of a beam 36 which extends below and is affixed to the spaced apart guide members 18 . it will be appreciated that initially the main frame 10 and the hoist machine carriage 22 are positioned at a lower level in the associated elevator hoistway to receive the hoist machine 30 . the hoist machine 30 is typically positioned on the carriage 22 so that only minimal movement thereof will be required to effect proper alignment of the base 32 and the support 34 . once the hoist machine 30 is suitably positioned on the carriage 22 , hoist ropes , not shown , are connected to the cross beam 36 and the entire main frame 10 , the carriage support 22 , and the hoist machine 30 are lifted to the uppermost position illustrated in fig1 . when the assemblage reaches this position , machine carriage 22 is caused to be slid horizontally over the horizontal guide members 18 to a position where the base 32 of the hoist machine 30 is superposed over the support 34 and the attachment holes are aligned . finally , the main frame 10 is lowered slightly allowing the entire load of the hoist machine 30 to be carried by the support 34 , and the machine carriage 22 is caused to be slid horizontally away from guide rails 12 and lowered to a lower position . the aforedescribed system may be effectively utilized to lift , lower , and position an elevator hoist machine into operative position on the upper terminals of guide rails in an elevator hoistway which does not have a conventional machine room . guidance for the system is typically achieved by the rails of a previously installed elevator guide rail system . also , the system permits the location or placement of an elevator hoisting machine in the open elevator shaft area between the guide rails and provides a means to shift the position of the machine laterally over the machine supporting structure at the top of the guide rails . further , the system may be satisfactorily used in low overhead shaft conditions where conventional hoisting means would require building alterations and could not be employed . in accordance with the provisions of the patent statutes , the present invention has been described in what is considered to represent its preferred embodiment . however , it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope .