In 1960s Europe there was still a high demand for treadle machines. The 401G and 401M (Monza, Italy) are treadleable. The bobbin winder of the 401A would have been in the way of the treadle belt. Check out Miriam's thread where you can see the 401G set up as a treadle:
http://www.quiltingboard.com/vintage...s-t211311.html