The gantries and ladders can have many different designs. They can have fixed length or they can be extendable. They can either be straight, curved or special design. Sometimes the gantries are equipped with monorail tracks underneath, allowing a suspended platform to access the whole area beneath the gantry. This is a typical solution for internal atriums giving access to not only the glass roof, but also lamps, sensors, fire protection etc. which has to be inspected and replaced from time to time.