Drive assembly

A drive assembly for providing a driving force, the assembly comprising:

• a first track along which a first vehicle is arranged to travel, the first track being declined in a first direction through a first declination;
• a second track along which a second vehicle is arranged to travel, the second track comprising a first portion which extends in a second direction in a substantially horizontal configuration, and a second portion which is arranged to pivot with respect to the first track between a first position in which the second portion is substantially coincident with the first portion and a second position in which the second portion is declined in the second direction through a second declination;
• a drive shaft coupled to the first and second vehicle, the drive shaft being arranged to rotate in dependence of the travel of the first and second vehicles along the respective tracks;
• wherein,
• the first vehicle is arranged to travel along the first track between a first drive location and a first idle location to drive the shaft in a first direction and to cause the second vehicle to travel along the first portion of the second track between a second idle location and a second drive location;
• and,
• the second vehicle is arranged to travel along the second portion from the second drive location to the second idle location to cause the drive shaft to rotate in a second direction and to cause the first vehicle to travel from the first idle location to the first drive location.