Concern about smoke and steam in the tunnels led to new designs of steam locomotive. Before the line opened in 1861 trials were made with the experimental "hot brick" locomotive nicknamed Fowler's Ghost. This was unsuccessful and the first public trains were hauled by broad gauge GWR Metropolitan Class condensing 2-4-0 tank locomotives designed by Daniel Gooch. They were followed by standard gauge GNR locomotivesincludeonly> until the Met received its own 4-4-0 tank locomotives. The locomotives were built by Beyer Peacock of Manchester. Their design is frequently attributed to the Met's Engineer John Fowler, but the locomotive was a development of one Beyers had built for the Spanish Tudela to Bilbao Railway, Fowler only specifying the driving wheel diameter, axle weight and the ability to