Tay Bridge disaster warned of their unreliability, and declined to estimate conditions at Dundee from readings taken elsewhere. One modern interpretation of available information suggests winds were gusting to . Usage of the bridge was restricted to one train at a time by a signalling block system using a baton as a token. At 7:13 p.m. a train from the south (consisting of a 4-4-0 locomotive, its tender, five passenger carriages, and a luggage van (brake van) slowed to pick up the baton from the signal cabin at the south end of the bridge, then headed out onto the bridge, picking up speed.
Tay Rail Bridge of the top of the section below. The joint was then secured by bolts through matching holes on lugs (Crumlin) or flanges (Belah) on the two sections. This 'spigot and faucet' configuration was used (apparently without machining) on some Tay Bridge pier columns, but on some the bolts were relied upon to ensure correct alignment. (In the event, the joints were made using undersized bolts. This gave greater tolerances when assembling the column, but the less positive alignment of the column joints as initially assembled and after any subsequent 'working' of the joint would have weakened the column). On the