The steam locomotives Phönix , Meteor , Titan and Pluto were passenger train locomotives of the KFNB . They were supplied by the Sharp, Roberts & Co. locomotive factory in 1841 and had the axle formula 1A1. A noticeable feature of these machines was the curved frame on the drive axle. On delivery, the dimensions of the locomotives, with the exception of the diameter of the running wheels, were the same as those of the eagle and arrow, which were also supplied for KFNB . However, modifications were made to the boiler and wheels , so that the dimensions later differed. For the first time, counterweights were attached over three spokes of the driving wheels.