In the meantime I progressed from Golmud into the highland of eastern Tibet (former Amdo province of Tibet) which nowadays belongs to Qinghai province.
On a map I found in one of the containers I slept in I found a road in construction which considerably would reduce my riding distance to Chengdu. As the Chinese are very quick in building new infrastructure I found out that this new road is a full blown motorway which in most parts is already finished or very close to finished. It leads from Golmud eastbound and then southeast till the border to Sichuan province.
From Golmud I still used the old State highway which has 2 lanes (1 per direction) and is heavily used by big 40 tons trucks whereas the parallel new motorway with 2 lanes per direction is almost empty, maybe 20 vehicles per hour.
In Xianride where the new motorway branches off into the mountains I could not convince the guards at the toll station to let me through but in contrast their proposal of a 3-500 km detour via Xining was not was I intended to do.
At least I got the 'hint' to quietly enter the new motorway a bit apart by climbing the fence. Usually Chinese motorways are rigorously fenced off about 1.80 m high with ten rows of barbed wire to keep animals and local people away and it is not possible to surpass it with a loaded bicycle. But I knew that at places where the fence cuts long lasting walking trails of men and animals it is often partly torn down. I found such a spot and with the help of two locals, a father and his ca 12 year old son, I could get the bicycle and the luggage through the fence without puncture and up the steep dam.
The first 80 km the motorway went parallel to a province road into the mountains, now with even less traffic of maybe 10 cars per hour. Later it was the only way of travel without a parallel road and crossed a 4450 m high pass. I felt the altitude and was quite slow. A bit before the pass I was stopped by the traffic police but not to send me off the motorway but instead to make some selfies with this crazy long-nosed foreigner.
The next day the motorway was partly under construction, 95 % finished, with lane labels and some parts of the guard rails missing. Only in one case the summit tunnel of a pass was not yet completed and i had to use the old gravel road to climb additional 200 m to a very impressive mountain pass (4600 m) next to a glacier.
At the second pass the summit tunnel was in similar state but a engineer gave me a sign and waved me to the left pipe. Ceiling, walls and floor was finished but sidewalks, cables and cross connections to the other pipe where heavily under construction and in some places big machines or a scaffold had to be circumnavigated. Most of the 5 km was dimly or not at all lit hence I was glad to have a light at the bicycle.
After 3 days in the mountains I am now in the county capital Golog or Maqin on 3700 m. The milage the last days was low, only around 120 km, but I felt the average altitude of 4000 m considerably.
Probably 7 more days on in the mountains to come, before I will be down in Chengdu.