The trade over the Great Lakes and Erie Canal was without doubt the most important feature of the commerce between the Atlantic States and the interior of the country between 1830 and 1860, but this route by no means absorbed all the traffic. The Main Line of the Pennsylvania canal system, completed in 1832, made it possible for Philadelphia and Baltimore to retain some of their trade with the cities of the Ohio Valley, but this trade, like the wagon trade preceding it, was largely one-sided, the westbound movement of light merchandise exceeding the eastbound movement of agricultural produce. The inclined planes which carried the traffic across the mountains proved to be an expensive and cumbersome device, and because of a lack of better transportation facilities, the trade of Philadelphia and Baltimore suffered constant losses, and for a time it seemed that New York was destined to monopolize the entire commerce between the Atlantic coast and the trans-Appalachian region. In 1841, however, this situation was modified by the entrance of a new factor--the Western Railroad, the completion of which gave through rail connection between Boston and Albany. Because of its isolated position Boston had not shared in the direct trade with the Central States, but had been compelled to buy and sell through the merchants of New York and Philadelphia. The new railroad completely altered the position of Boston and brought an era of great prosperity to the city, at the same time demonstrating the practicability of the steam road as a carrier of nearly all kinds of freight.