This weird looking coupling system actually worked. The modeller said that getting the model to work properly was difficult as for when the prototype was built.
During the first weeks of 1848 E. Wilson and Co., of the Railway Foundry, Leeds, turned out a remarkable specimen of locomotive construction ; the engine in question was named Lablache (after a celebrated singer). This locomotive had two inside cylinders 16in. diameter, 20in. stroke, and was supported on four wheels each 7ft.diameter; the wheelbase was 16ft.
It is necessary to describe the mode of working introduced into the Lablache. Between the two pairs of wheels was a straight bar, or shaft, extending under the boiler, parallel with the axles, and projecting on each side beyond the frames. Between the frames two levers were attached to this shaft, and the other extremities of these levers were attached to the pistons by the usual piston-rod and connecting-rods. Now comes the difference in working ; the driving axle, it will be observed, was not cranked, but provided with arms.
The axle did not revolve, but simply oscillated backwards and forwards. Outside the frames were double-ended levers, one end being coupled to a crank on the leading wheel, and the opposite end connected in a similar manner to the trailing wheels. The wheels on both sides of the locomotive were connected in the same way that a rotary motion is communicated to a lathe by a treadle. When first constructed India- rubber springs were provided for this engine’s bearings.
Sekon, G. A. (1899). The Evolution of the Steam Locomotive -1803 to 1898: The Railway Publishing Co.