Yes exactly this was to have a alternative between the PS prompt-pump and FP basic pump. This rig was followed by many other models and generations until beginning 2000. Nowadays there are almost no more units in service in France.
JP - Thanks! Do you happen to know the water tank capacity of these FM pumpers? At this time, new postwar specification British urban pumpers had a tank between 350 and 450 litres, while the new German LF 16 had 800. The British and German FPT equivalents were 1800 and 2400 liters respectively. By 1950 American “triple combination” pumpers also had larger water tanks than before WWII. While these varied a lot, they were usually around 1000 to 1200 litres.
Added by Rob Johnson on 21 March 2024.