In the context of the telegraphic distribution of Greenwich time, while the early experiments, the roles of successive Astronomers Royal in its expansion, and its impacts on the standardization of time in Victorian Britain have all been evaluated, the attempts of George Biddell Airy and his collaborators in constructing the Royal Observatory's time signals as the authoritative source of standard time have been underexplored within the existing historical literature. This paper focuses on the wide-ranging activities of Airy, his assistant astronomers, (...) telegraph engineers, clockmakers and others, which served to increase the reliability of the Royal Observatory's time service between the 1850s and 1870s. Airy and his collaborators aimed to mechanize and automate their telegraphic time distribution system in order to improve its accuracy and reliability. The accomplishment of such technological innovations was disseminated via public lectures, journal articles and correspondence with experts, secondary distributors of standard time and the general public. These communications were used to build public trust in the Greenwich time service. However, the unexplored archival material used in the present paper provides fresh insight into the unstable nature of the Greenwich time system, including its clear limits in terms of its scale of automation and degree of accuracy. (shrink)