Only days ahead of the French Army in April 1945, Ott-Helmuth von Lossnitzer and about 250 Mauser engineers and technicians fled Oberndorf with the core of Mauser's new projects. They had the drawings, components, and gages for guns like the new StG-45 assault rifle, MK214 aircraft cannon, and Volkspistol and they were headed for an impregnable series of tunnels in the Austrian Alps to carry on the war. In a story that is absolutely worthy of film adaptation they scrounged a series of locomotives, dodged P47 Thunderbolt attacks, and went careening through the Alps with about 2 dozen boxcars of the most important prototype guns in the German arsenal.

Of course, the idea of continued resistance was a complete fantasy. When it did finally arrive in Ötztal, the Mauser refugees found all the tunnels already occupied by other groups with the very same idea. So they basically made camp and waited for American forces to arrive. The train was found by a British-American CIOS (Combined Intelligence Objective Subcommittee) party, the engineers were all questioned, and the train contents packed up for shipment to the UK and US. Ott-Helmuth von Lossnitzer himself emigrated to the US as part of Operation Paperclip, where he worked for Springfield Arsenal for many years until retiring in 1968 and then living in Wisconsin until his passing in 1989.

For anyone interested in this story, I highly recommend Lossnitzer's oral recollections compiled into book form by Leslie Field and Bas Martens - ISBN 9789081737807. It is out of print now, but you may be able to find it on the secondary market.

Much more accessible is the reprinting of the original CIOS report on Mauser published by Peter Dallhammer (whom you may recall from his Textbook of Pistol Technology and Design). This is a 360-page treasure trove of details on Mauser's ongoing R&D in 1945, and it is available on Amazon.