The first section of the track between Mettupalayam and Kallar is adhesion worked. Beyond Kallar with the Nilagiris looming large, the ruling gradient rises steeply to 1 in 12; this section of the track is the rack section - the taxing yet thrilling part of the ride which can be handled only by the sturdy 'X' class locos which take on the sharp gradient by operating on the rack and pinion mechanism.