Trolley Unit
![A trolley unit suspended from a lifting joist running on the roof](http://maintainability.com.sg/wp-content/uploads/2016/06/Screen-Shot-2016-10-28-at-11.28.19-PM.png)
The trolley unit is also known as the Building Maintenance Unit (BMU), or a roof-car. It is a machine equipped with an integrated lifting hoist, a jib and a cradle and running on the roof of a building.
It allows complete access to all external parts of the building at the touch of a button. Its movements are controlled safely from the push-button control panel. Access to the cradle and to its garage is from the roof and the operator has nothing to assemble or dismantle. The built-in safety devices control and monitor the operations of the unit to ensure safety.
The most commonly used trolley unit system used in the region are:
![Fig 2 (Source: The TRACTEL Group)](http://maintainability.com.sg/wp-content/uploads/2016/06/Screen-Shot-2016-10-28-at-11.28.25-PM.png)
![(Source: MHE DEMAC)](http://maintainability.com.sg/wp-content/uploads/2016/06/Screen-Shot-2016-10-28-at-11.28.35-PM.png)
![(Source: The TRACTEL Group)](http://maintainability.com.sg/wp-content/uploads/2016/06/Screen-Shot-2016-10-28-at-11.28.41-PM.png)
Cases
![tcase1](http://maintainability.com.sg/wp-content/uploads/2016/06/tcase1-150x150.jpg)
![tcase2](http://maintainability.com.sg/wp-content/uploads/2016/06/tcase2-150x150.jpg)
![tcase3](http://maintainability.com.sg/wp-content/uploads/2016/06/Tcase3-150x150.jpg)
![tcase4](http://maintainability.com.sg/wp-content/uploads/2016/06/tcase4-150x150.jpg)
![tcase5](http://maintainability.com.sg/wp-content/uploads/2016/06/tcase5-150x150.jpg)
![tcase6](http://maintainability.com.sg/wp-content/uploads/2016/06/tcase6-150x150.jpg)
![tcase7](http://maintainability.com.sg/wp-content/uploads/2016/06/tcase7-150x150.jpg)
![tcase8](http://maintainability.com.sg/wp-content/uploads/2016/06/tcase8-150x150.jpg)