Using a spherical joint as opposed to a universal joint also eliminates the problematic possibility of a Plain spherical bearings can be used in place of SRJs at the cost of increased friction, but offer an opportunity to preload the joint further.
12.
To enable them to negotiate radius curves, the leading coupled wheels were given a total side-play in their horn blocks, while the tyre flanges of the intermediate coupled wheels were of reduced thickness and the leading coupling rods were provided with spherical bearings at the knuckle joints and crank pins.
13.
This driving axle had a lateral play of about 20 mm, and spherical bearings were used on the cranks and coupling rods to this axle . ( The engine used inside cylinders driving the middle set of drivers . ) The first two axles worked together to guide the locomotive, similar to a conventional leading bogie.
