article by Robert Jack, appeared in BJRP 105, pages 70 – 77

IMAGE “The second example shows the route up and running at full speed. It is endorsed “Via Moskwa Moskau” and leaves Kabul on 30 December 1939, transits Mazar-i-Sharif on 2 January and arrives at Brandenburg (Havel) on 19 January 1940 (transit time 21 days) (Fig. 2). Note that German censorship has now been introduced.”

Full article here.
70-77 Robert Jack - THE NORTHERN ROUTE