 This extra service was sometimes a carriage train hauled by locomotives such as the UD class and sometimes a railcar service employing the experimental Sentinel-Cammell steam railcar.However, the opening of the East Coast Main Trunk Railway through to the Bay of Plenty in 1928 significantly reduced Thames's importance as a terminus.With the introduction of a direct express to the Bay of Plenty, the "Taneatua Express", the "Thames Express" was superfluous and unnecessary, and accordingly ceased to operate.