Parallel to S16, Al decides to study with the OCEM a very powerful engine goods whose two prototypes are built in Graffenstaden in 1936. The network has at that time the most advanced park and most efficient of Décapod in France with its G12 and G12.1. These machines, which have at this time more than 20 years of service, had been produced within the weight limit per axle of 17 tons. G16 aim at the 20 tons per axle, which must allow dimensions and the powers highest possible. The frame is out of steel bars of 140mm thickness, the combined suspensions and the wheels of 1,5m of diameter. The very long boiler has a hearth identical to that of S16 with a combustion chamber and a tube bank of almost 6 meters. Limps with smoke shelters the superheater collector and an exhaust doubles Kylchap. The heaters are this time laid out in a careenage placed behind the sand pit on the first shell ring. Wagner screens cut in bevel with AR improve the modern aspect of the 5901. Bissel AR carries an auxiliary engine (booster rocket). The choice of the engine tricylindres of G12 does not make it possible any more to assemble the Caprotti distribution under the axis of the boiler. So one limps with gears is assembled on contre-manivelle of the driving axle which transmits the rotary movement to limps with cams on the blocks cylinders. What explains the presence of this very long stem inclined under the apron. The engine torque is transmitted entirely by the third coupled wheel, the median driving rod actuates a dropped axle there and the external driving rods act on this same wheel. Because of the lack of place, one is obliged to mount a crank on the second axle to allow the low displacement of the median rod. G16 are also stamped with 20 Bars and have an enormous grid of 5 m2. Nevertheless compared to S16, one already returned from the copper hearth to steel. They are limited to 65 km/h. The total length of the machine hardly leaves latitude for the tender assembled on three axles for 25 m3 of water. It is in fact very disproportionate but it is the price to pay to preserve the access to the revolving bridges of 20 meters.