FMG 9551 and 10552 in Thomas Yard, November 28, 2021 with tanks as a booster waggon trial. Twenty pairs, or forty waggons numbered 9551 slave and 10552 control, up to 9589 slave and 10590 control built by CRRC Qiqihar in 2021 with the CNR style body and yellow ends denoting dual rotary coupler waggons.