After further experiments and improvements, Hancock finally made a vehicle to travel on three wheels, getting power from a pair of vibrating or trunnion engines fixed upon the crank-axle of the fore wheels. Experimental trips of this carriage were made from the Stratford shop to Epping Forest, Paddington, Hounslow, Croydon, Fulham, and elsewhere. Some changes were made in the vehicle, and finally the trunnion engines were put aside and fixed ones substituted. This improved carriage, the first in a long series built by Hancock, was named the Infant. The body was in the form of a double-body coach, or omnibus, with seats for passengers inside and out. The bulk of the machinery was placed in the rear of the carriage, a boiler and a fire being beneath it. Between the boiler and the passengers' seats was the engine and a place for the engineer. A pair of inverted fixed engines working vertically on a crank-shaft furnished the power. The steering apparatus was in front. The whole carriage was on one frame supported by four springs on the axle of each wheel. The carriage was capable of carrying sixteen passengers besides the engineer and guide. Its total weight, including coke and water, but exclusive of attendants and passengers, was about three and one-half tons. The wheel tires were three and one-half inches wide, and the diameter of the hind wheels four feet. In February, 1831, the Infant began to run on regular trips between Stratford and London. In 1832 a second carriage, similar to the Infant, was built, and called the Era. It was constructed for the London and Brighton Steam Carriage Company, to ply between London and Greenwich. The following year a third carriage, the Enterprise, was completed, for the London and Paddington Steam Car Company, and was run between London and Paddington. Hancock took the Infant on a long trip from Stratford to London and Brighton, in October, 1832. Eleven passengers were carried, and the carriage kept a speed of nine miles an hour on the level, and six to eight miles an hour up grade. On the return one mile up hill was made at the rate of seventeen miles an hour. Another trip to Brighton was made in September of the next year at an average speed of twelve miles an hour actual traveling. At Brighton the new carriage attracted much attention, and was exhibited for several days on trips in and around the town. After the Enterprise, the Autopsy came from the Hancock shops, in September, 1833. This carriage was run on trial about Brighton and in London streets, and for about a month was run for hire between Finsbury Square and Pentonville.