On the east, the main cordillera abuts upon the region of plateaus and savannas, which occupies nearly half of the area of Nicaragua.
Passengers and goods are generally in different and sometimes in distant positions, the place selected for each being that which is most convenient for the traffic. The passenger station abuts on the main line, or, at termini, forms the natural terminus, at a place as near as can conveniently be obtained to the centre of the population which constitutes the passenger traffic; and preferably its platforms should be at or near the ground level, for convenience of access.
The north - eastern portion of the Afghan tableland abuts on the Himalaya and Tibet, with which it forms a continuous mass of mountain between the 71st and 72nd meridians, and 34° and 36° N.
Tibet, the Kalta-alaghan does not decrease, but it increases in elevation towards the east, where, like the Chimen-tagh, it abuts upon and merges in the ranges that border Tsaidam on the south.