The trail on the piles

There were and are many technical difficulties for such a railway. About half of the second section was built on barely permanent permafrost. In the summer, the uppermost layer thaws, and the ground becomes muddy. Chinese engineers dealt with this problem by building elevated tracks with foundations sunk deep into the ground, building hollow concrete pipes beneath the tracks to keep the rail bed frozen, and using metal sun shades. Similar to the Trans-Alaska Pipeline System portions of the track are also passively cooled with ammonia based heat exchangers.