So tibet railways section used
Chinese 25G rolling stock which is permissible for 120 kmph only but top speed 140+
That means too tibet railways have top speed of 120 kmph
Well i saw documentary in which they stated that 160 kmph trains runs on that area
....
more...

Well if we see that china runs 120 kmph speed at tibet region thats a very big thing too bcoz at same time we in J&K cant run at fast speed
Coaches are capable but not section

Tibet trains rolling stock information:
25G rolling stocks used
25.5m long
120 top speed allowed
140 can go
Disc...
more...

& flange braking system
AAR coulings
.
It is similar with vande bharat where coaches were attached and both coaches were attach in that manner that no air can pass in it
Hence no reduction in speed by air
Having double layer windows too not as metro where when 2 trains surpass each other both metro coaches windows feels shaky