The Daleks were one of the few species in the universe to master temporal engineering. Until shortly before the Time War between the Daleks and the Time Lords of Gallifrey, Dalek technology allowed their time ships to travel backwards and forwards in time via relatively crude "Time Corridors". This was litterally the process of creating a direct link between two space / time co-ordinates. The Dalek Time ship created these corridors, through which it would then travel.
The Daleks managed to transcend this level of Time Travel before the Time War. All Dalek vessels in the Time War were capable of temporal travel.
Early Dalek time ships mimicked Time Lord Technology to an extent, based as it was on encounters with the Doctor and his malfunctioning TARDIS. The ships were dimensionally transcendental (bigger inside than outside) similar to the vessels used by the Time Lords. The interior of the ship existed in a pocket dimension, allowing the exterior of the ship to be far smaller than would otherwise be necessary to house the temporal engines and vast computer systems required to operate the ships safely. The early timecraft resembled silver cubes - each side measuring around eleven foot. The small size of the ship enabled the Daleks to land in enclosed spaces with little difficulty, enhancing the tactical use of the time-craft to the Dalek Empire.
The Chase, The Dalek Masterplan
