Britain’s nineteenth-century railway companies traditionally play a central role in histories of the spread of standard Greenwich time. This relationship at once seems to embody a productive relationship between science and capitalism, with regulated time essential to the formation of a disciplined industrial economy. In this narrative, it is not the state, but capitalistic private commerce which fashioned a national time system. However, as this article demonstrates, the collaboration between railway companies and the Royal Greenwich Observatory was far from harmonious. While railways did employ the accurate time the Observatory provided, they were also more than happy to compromise the astronomical institution’s ability to take the accurate celestial observations such time depended on. Observing astronomical transits required the use of troughs of mercury to reflect images of stars, but the construction of a railway too near to the Observatory threatened to cause vibrations which would make such readings impossible. Through debates over proposed railway lines near the Observatory, it becomes clear how important government protection from private interests was to preserving astronomical standards. This article revises our understanding of the role of railway companies in the dissemination of standard time and argues that state intervention was essential to preserving Victorian British astronomical science.