In 1839, the Philadelphia & Reading ordered a 4-4-0 locomotive that was to be more powerful than other contemporary locomotives and would be named “Gowan & Marx”. It was designed by Joseph Harrison Jr. who had built the first locomotive with an equalizing lever two years earlier. He improved this lever to a design that was also to be used on thousands of later locomotives. This layout, together with a firebox that was carried above the rear driving axle, allowed to build a heavy and powerful locomotive that had no problems when running over uneven tracks.

It weighed somewhat more than 12 tons and had drivers with a diameter of 42 inches. The grate had an area of 12 square feet and originally burned wood. On a demonstration run in 1840, it hauled a train of 423 tons with an average of 9.82 mph. Although the safety valves had been set so a higher pressure, this train consisted of 101 or 104 cars. After this, the Russian Emperor awarded a huge contract for the construction of a large number of locomotives and cars for the Moscow-St. Petersburg line to Harrison and his partners. The “Gowan & Marx” was switched to coal burning in 1855 and operated until around 1860.